Changelog updated

Change themes in random order once a day/hour (#62 )
template docs added
2024-08-30 18:22:40 +00:00 · 2022-02-01 20:12:11 +05:00 · 2022-02-01 19:39:50 +05:00 · 2022-01-31 14:45:12 +05:00 · 2022-01-31 13:53:06 +05:00 · 2022-01-31 13:45:22 +05:00
37 changed files with 779 additions and 94 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@ -15,7 +15,7 @@ jobs:
        arch: [amd64]  # amd64, 386
    steps:
      - uses: actions/setup-go@v2
-        with: {go-version: 1.17.5}
+        with: {go-version: 1.17.6}

      - uses: actions/checkout@v2

--- a/.golangci.yml
+++ b/.golangci.yml
@ -42,7 +42,9 @@ linters: # All available linters list: <https://golangci-lint.run/usage/linters/
  disable-all: true
  enable:
    - asciicheck # Simple linter to check that your code does not contain non-ASCII identifiers
+    - bidichk # Checks for dangerous unicode character sequences
    - bodyclose # Checks whether HTTP response body is closed successfully
+    - contextcheck # check the function whether use a non-inherited context
    - deadcode # Finds unused code
    - depguard # Go linter that checks if package imports are in a list of acceptable packages
    - dogsled # Checks assignments with too many blank identifiers (e.g. x, _, _, _, := f())
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -4,12 +4,37 @@ All notable changes to this package will be documented in this file.

 The format is based on [Keep a Changelog][keepachangelog] and this project adheres to [Semantic Versioning][semver].

+## v2.6.0
+
+### Added
+
+- Possibility to change the template to the random once a day using "special" template name `random-daily` (or hourly, using `random-hourly`) [#48]
+
+[#48]:https://github.com/tarampampam/error-pages/issues/48
+
+## v2.5.0
+
+### Changed
+
+- Go updated from `1.17.5` up to `1.17.6`
+
+### Added
+
+- `Host` and `X-Forwarded-For` Header to error pages [#61]
+
+### Fixed
+
+- Performance issue, that affects template rendering. Now templates are cached in memory (for 2 seconds), and it has improved performance by more than 200% [#60]
+
+[#60]:https://github.com/tarampampam/error-pages/pull/60
+[#61]:https://github.com/tarampampam/error-pages/pull/61
+
 ## v2.4.0

 ### Changed

 - It is now possible to use [golang-tags of templates](https://pkg.go.dev/text/template) in error page templates and formatted (`json`, `xml`) responses [#49]
- Health-check route become `/healthz` (instead `/health/live`, previous route marked ad deprecated) [#49]
+- Health-check route become `/healthz` (instead `/health/live`, previous route marked as deprecated) [#49]

 ### Added

--- a/2
+++ b/2
@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1.2

 # Image page: <https://hub.docker.com/_/golang>
-FROM golang:1.17.5-alpine as builder
+FROM golang:1.17.6-alpine as builder

 # can be passed with any prefix (like `v1.2.3@GITHASH`), e.g.: `docker build --build-arg "APP_VERSION=v1.2.3@GITHASH" .`
 ARG APP_VERSION="undefined@docker"
--- a/README.md
+++ b/README.md
@ -26,7 +26,7 @@ One day you may want to replace the standard error pages of your HTTP server wit
  - Writes logs in `json` format
  - Contains healthcheck endpoint (`/healthz`)
  - Contains metrics endpoint (`/metrics`) in Prometheus format
- Lightweight docker image _(~3.7Mb compressed size)_, distroless and uses the unleveled user by default
+- Lightweight docker image _(~4.3Mb compressed size)_, distroless and uses the unleveled user by default
 - [Go-template](https://pkg.go.dev/text/template) tags are allowed in the templates
 - Ready for integration with [Traefik][traefik] ([error pages customization](https://doc.traefik.io/traefik/middlewares/http/errorpages/)) and [Ingress-nginx][ingress-nginx]
 - Fully configurable (take a look at the [configuration file](https://github.com/tarampampam/error-pages/blob/master/error-pages.yml) and [project Wiki][wiki])
@ -53,7 +53,7 @@ Please, take a look at [our Wiki][wiki] for the common usage stories:
 - [Pages generator][wiki-generator] (build your own error page set)
 - [Static error pages][wiki-static-error-pages] (extract generated static error pages from the docker image)
 - [Usage with nginx][wiki-usage-with-nginx] (include our error pages into an image with nginx)
- [Usage with Traekik and local Docker Compose][wiki-traefik-docker-compose] (it's a good starting point for the tests)
+- [Usage with Traefik and local Docker Compose][wiki-traefik-docker-compose] (it's a good starting point for the tests)
 - [Usage with Traefik and Docker Swarm][wiki-traefik-swarm]
 - [Kubernetes & ingress nginx][wiki-k8s-ingress-nginx]

@ -80,25 +80,26 @@ $ ulimit -aH | grep file
 -n: file descriptors                1048576
 -x: file locks                      unlimited

-$ wrk --version | head -n 1
-wrk 4.2.0 [epoll] Copyright (C) 2012 Will Glozer
+$ docker run --rm -p "8080:8080/tcp" -e "SHOW_DETAILS=true" error-pages:local # in separate terminal

-$ wrk -t12 -c400 -d30s http://127.0.0.1:8080/500.html
-Running 30s test @ http://127.0.0.1:8080/500.html
+$ wrk --timeout 1s -t12 -c400 -d30s -s ./test/wrk/request.lua http://127.0.0.1:8080/
+Running 30s test @ http://127.0.0.1:8080/
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
-    Latency    50.06ms   61.15ms 655.79ms   85.54%
-    Req/Sec     1.07k   363.14     2.40k    69.24%
-  383014 requests in 30.08s, 2.14GB read
-Requests/sec:  12731.07
-Transfer/sec:     72.79MB
+    Latency    10.84ms    7.89ms 135.91ms   79.36%
+    Req/Sec     3.23k   785.11     6.30k    70.04%
+  1160567 requests in 30.10s, 4.12GB read
+Requests/sec:  38552.04
+Transfer/sec:    140.23MB
 ```

-FS & memory usage stats during the test:
+<details>
+  <summary>FS & memory usage stats during the test</summary>

-<p align="center">
-  <img src="https://hsto.org/webt/dy/2e/_8/dy2e_8xkefxre7z5w7xcorjldmm.png" alt="" />
-</p>
+  <p align="center">
+    <img src="https://hsto.org/webt/ts/w-/lz/tsw-lznvru0ngjneiimkwq7ysyc.png" alt="" />
+  </p>
+</details>

 ## 🪂 Templates

--- a/docker-compose.yml
+++ b/docker-compose.yml
@ -8,7 +8,7 @@ volumes:

 services:
  app: &app-service
-    image: golang:1.17.5-buster # Image page: <https://hub.docker.com/_/golang>
+    image: golang:1.17.6-buster # Image page: <https://hub.docker.com/_/golang>
    working_dir: /src
    environment:
      HOME: /tmp
--- a/error-pages.yml
+++ b/error-pages.yml
@ -21,7 +21,9 @@ formats:
        "message": {{ message | json }},
        "description": {{ description | json }}{{ if show_details }},
        "details": {
+          "host": {{ host | json }},
          "original_uri": {{ original_uri | json }},
+          "forwarded_for": {{ forwarded_for | json }},
          "namespace": {{ namespace | json }},
          "ingress_name": {{ ingress_name | json }},
          "service_name": {{ service_name | json }},
@ -39,7 +41,9 @@ formats:
        <message>{{ message }}</message>
        <description>{{ description }}</description>{{ if show_details }}
        <details>
+          <host>{{ host }}</host>
          <originalURI>{{ original_uri }}</originalURI>
+          <forwardedFor>{{ forwarded_for }}</forwardedFor>
          <namespace>{{ namespace }}</namespace>
          <ingressName>{{ ingress_name }}</ingressName>
          <serviceName>{{ service_name }}</serviceName>
--- a/go.mod
+++ b/go.mod
@ -4,7 +4,7 @@ go 1.17

 require (
 	github.com/a8m/envsubst v1.3.0
-	github.com/fasthttp/router v1.4.4
+	github.com/fasthttp/router v1.4.5
 	github.com/fatih/color v1.13.0
 	github.com/kami-zh/go-capturer v0.0.0-20171211120116-e492ea43421d
 	github.com/pkg/errors v0.9.1
@ -13,26 +13,26 @@ require (
 	github.com/spf13/cobra v1.3.0
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.7.0
-	github.com/valyala/fasthttp v1.31.0
-	go.uber.org/zap v1.19.1
+	github.com/valyala/fasthttp v1.33.0
+	go.uber.org/zap v1.20.0
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )

 require (
-	github.com/andybalholm/brotli v1.0.3 // indirect
+	github.com/andybalholm/brotli v1.0.4 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
-	github.com/klauspost/compress v1.13.6 // indirect
+	github.com/klauspost/compress v1.14.1 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/common v0.32.1 // indirect
 	github.com/prometheus/procfs v0.7.3 // indirect
-	github.com/savsgio/gotils v0.0.0-20210921075833-21a6215cb0e4 // indirect
+	github.com/savsgio/gotils v0.0.0-20211223103454-d0aaa54c5899 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
 	go.uber.org/multierr v1.6.0 // indirect
--- a/go.sum
+++ b/go.sum
@ -58,8 +58,8 @@ github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRF
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
 github.com/andybalholm/brotli v1.0.2/go.mod h1:loMXtMfwqflxFJPmdbJO0a3KNoPuLBgiu3qAvBg8x/Y=
-github.com/andybalholm/brotli v1.0.3 h1:fpcw+r1N1h0Poc1F/pHbW40cUm/lMEQslZtCkBQ0UnM=
-github.com/andybalholm/brotli v1.0.3/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
+github.com/andybalholm/brotli v1.0.4 h1:V7DdXeJtZscaqfNuAdSRuRFzuiKlHSC/Zh3zl9qY3JY=
+github.com/andybalholm/brotli v1.0.4/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da/go.mod h1:Q73ZrmVTwzkszR9V5SSuryQ31EELlFMUz1kKyl939pY=
@ -113,8 +113,8 @@ github.com/envoyproxy/go-control-plane v0.9.10-0.20210907150352-cf90f659a021/go.
 github.com/envoyproxy/go-control-plane v0.10.1/go.mod h1:AY7fTTXNdv/aJ2O5jwpxAPOWUZ7hQAEvzN5Pf27BkQQ=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/envoyproxy/protoc-gen-validate v0.6.2/go.mod h1:2t7qjJNvHPx8IjnBOzl9E9/baC+qXE/TeeyBRzgJDws=
-github.com/fasthttp/router v1.4.4 h1:Z025tHFTjDp6T6QMBjloyGL6KV5wtakW365K/7KiE1c=
-github.com/fasthttp/router v1.4.4/go.mod h1:TiyF2kc+mogKcTxqkhUbiXpwklouv5dN58A0ZUo8J6s=
+github.com/fasthttp/router v1.4.5 h1:YZonsKCssEwEi3veDMhL6okIx550qegAiuXAK8NnM3Y=
+github.com/fasthttp/router v1.4.5/go.mod h1:UYExWhCy7pUmavRZ0XfjEgHwzxyKwyS8uzXhaTRDG9Y=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL+zU=
 github.com/fatih/color v1.13.0 h1:8LOYc1KYPPmyKMuN8QV2DNRWNbLo6LZ0iLs8+mlH53w=
@ -259,8 +259,8 @@ github.com/kami-zh/go-capturer v0.0.0-20171211120116-e492ea43421d/go.mod h1:P2vi
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.13.4/go.mod h1:8dP1Hq4DHOhN9w426knH3Rhby4rFm6D8eO+e+Dq5Gzg=
-github.com/klauspost/compress v1.13.6 h1:P76CopJELS0TiO2mebmnzgWaajssP/EszplttgQxcgc=
-github.com/klauspost/compress v1.13.6/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
+github.com/klauspost/compress v1.14.1 h1:hLQYb23E8/fO+1u53d02A97a8UnsddcvYzq4ERRU4ds=
+github.com/klauspost/compress v1.14.1/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg=
@ -346,8 +346,8 @@ github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFR
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/sagikazarmark/crypt v0.3.0/go.mod h1:uD/D+6UF4SrIR1uGEv7bBNkNqLGqUr43MRiaGWX1Nig=
-github.com/savsgio/gotils v0.0.0-20210921075833-21a6215cb0e4 h1:ocK/D6lCgLji37Z2so4xhMl46se1ntReQQCUIU4BWI8=
-github.com/savsgio/gotils v0.0.0-20210921075833-21a6215cb0e4/go.mod h1:oejLrk1Y/5zOF+c/aHtXqn3TFlzzbAgPWg8zBiAHDas=
+github.com/savsgio/gotils v0.0.0-20211223103454-d0aaa54c5899 h1:Orn7s+r1raRTBKLSc9DmbktTT04sL+vkzsbRD2Q8rOI=
+github.com/savsgio/gotils v0.0.0-20211223103454-d0aaa54c5899/go.mod h1:oejLrk1Y/5zOF+c/aHtXqn3TFlzzbAgPWg8zBiAHDas=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
@ -375,8 +375,9 @@ github.com/subosito/gotenv v1.2.0/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69
 github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926/go.mod h1:9ESjWnEqriFuLhtthL60Sar/7RFoluCcXsuvEwTV5KM=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasthttp v1.31.0 h1:lrauRLII19afgCs2fnWRJ4M5IkV0lo2FqA61uGkNBfE=
-github.com/valyala/fasthttp v1.31.0/go.mod h1:2rsYD01CKFrjjsvFxx75KlEUNpWNBY9JWD3K/7o2Cus=
+github.com/valyala/fasthttp v1.32.0/go.mod h1:2rsYD01CKFrjjsvFxx75KlEUNpWNBY9JWD3K/7o2Cus=
+github.com/valyala/fasthttp v1.33.0 h1:mHBKd98J5NcXuBddgjvim1i3kWzlng1SzLhrnBOU9g8=
+github.com/valyala/fasthttp v1.33.0/go.mod h1:KJRK/MXx0J+yd0c5hlR+s1tIHD72sniU8ZJjl97LIw4=
 github.com/valyala/tcplisten v1.0.0/go.mod h1:T0xQ8SeCZGxckz9qRXTfG43PvQ/mcWh7FwZEA7Ioqkc=
 github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@ -396,13 +397,13 @@ go.opencensus.io v0.23.0/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
 go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
 go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
-go.uber.org/goleak v1.1.11-0.20210813005559-691160354723 h1:sHOAIxRGBp443oHZIPB+HsUGaksVCXVQENPxwTfQdH4=
-go.uber.org/goleak v1.1.11-0.20210813005559-691160354723/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
+go.uber.org/goleak v1.1.11 h1:wy28qYRKZgnJTxGxvye5/wgWr1EKjmUDGYox5mGlRlI=
+go.uber.org/goleak v1.1.11/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
 go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
 go.uber.org/zap v1.17.0/go.mod h1:MXVU+bhUf/A7Xi2HNOnopQOrmycQ5Ih87HtOu4q5SSo=
-go.uber.org/zap v1.19.1 h1:ue41HOKd1vGURxrmeKIgELGb3jPW9DMUDGtsinblHwI=
-go.uber.org/zap v1.19.1/go.mod h1:j3DNczoxDZroyBnOT1L/Q79cfUMGZxlv/9dzN7SM1rI=
+go.uber.org/zap v1.20.0 h1:N4oPlghZwYG55MlU6LXk/Zp00FVNE9X9wrYO8CEs4lc=
+go.uber.org/zap v1.20.0/go.mod h1:wjWOCqI0f2ZZrJF/UufIOkiC8ii6tm1iqIsLo76RfJw=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20181029021203-45a5f77698d3/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@ -414,6 +415,7 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
 golang.org/x/crypto v0.0.0-20210817164053-32db794688a5/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.0.0-20220112180741-5e0467b6c7ce/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@ -493,6 +495,8 @@ golang.org/x/net v0.0.0-20210503060351-7fd8e65b6420/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20210510120150-4163338589ed/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20220111093109-d55c255bac03/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@ -591,6 +595,7 @@ golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211124211545-fe61309f8881/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211205182925-97ca703d548d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220111092808-5a964db01320/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9 h1:XfKQ4OlFl8okEOr5UvAqFRVj8pY/4yfcXrddB8qAbU0=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
--- a/internal/cli/build/command.go
+++ b/internal/cli/build/command.go
@ -71,7 +71,8 @@ func run(log *zap.Logger, cfg *config.Config, outDirectoryPath string, generateI
 		return errors.Wrap(err, "cannot prepare output directory")
 	}

-	history := newBuildingHistory()
+	history, renderer := newBuildingHistory(), tpl.NewTemplateRenderer()
+	defer func() { _ = renderer.Close() }()

 	for _, template := range cfg.Templates {
 		log.Debug("template processing", zap.String("name", template.Name()))
@ -86,7 +87,7 @@ func run(log *zap.Logger, cfg *config.Config, outDirectoryPath string, generateI
 				filePath = path.Join(outDirectoryPath, template.Name(), fileName)
 			)

-			content, renderingErr := tpl.Render(template.Content(), tpl.Properties{
+			content, renderingErr := renderer.Render(template.Content(), tpl.Properties{
 				Code:               page.Code(),
 				Message:            page.Message(),
 				Description:        page.Description(),
--- a/internal/cli/serve/command.go
+++ b/internal/cli/serve/command.go
@ -69,7 +69,7 @@ func run(parentCtx context.Context, log *zap.Logger, f flags, cfg *config.Config

 	var (
 		templateNames = cfg.TemplateNames()
-		picker        *pick.StringsSlice
+		picker        interface{ Pick() string }
 	)

 	switch f.template.name {
@ -83,6 +83,16 @@ func run(parentCtx context.Context, log *zap.Logger, f flags, cfg *config.Config

 		picker = pick.NewStringsSlice(templateNames, pick.RandomEveryTime)

+	case useRandomTemplateDaily:
+		log.Info("A random template will be used and changed once a day")
+
+		picker = pick.NewStringsSliceWithInterval(templateNames, pick.RandomEveryTime, time.Hour*24) //nolint:gomnd
+
+	case useRandomTemplateHourly:
+		log.Info("A random template will be used and changed hourly")
+
+		picker = pick.NewStringsSliceWithInterval(templateNames, pick.RandomEveryTime, time.Hour)
+
 	case "":
 		log.Info("The first template (ordered by name) will be used")

@ -132,6 +142,12 @@ func run(parentCtx context.Context, log *zap.Logger, f flags, cfg *config.Config
 	case <-ctx.Done(): // ..or context cancellation
 		log.Info("Gracefully server stopping", zap.Duration("uptime", time.Since(startedAt)))

+		if p, ok := picker.(interface{ Close() error }); ok {
+			if err := p.Close(); err != nil {
+				return err
+			}
+		}
+
 		// stop the server using created context above
 		if err := server.Stop(); err != nil {
 			return err
--- a/internal/cli/serve/flags.go
+++ b/internal/cli/serve/flags.go
@ -35,6 +35,8 @@ const (
 const (
 	useRandomTemplate              = "random"
 	useRandomTemplateOnEachRequest = "i-said-random"
+	useRandomTemplateDaily         = "random-daily"
+	useRandomTemplateHourly        = "random-hourly"
 )

 func (f *flags) init(flagSet *pflag.FlagSet) {
@ -55,8 +57,13 @@ func (f *flags) init(flagSet *pflag.FlagSet) {
 		templateNameFlagName, "t",
 		"",
 		fmt.Sprintf(
-			"template name (set \"%s\" to use a randomized or \"%s\" to use a randomized template on each request) [$%s]", //nolint:lll
-			useRandomTemplate, useRandomTemplateOnEachRequest, env.TemplateName,
+			"template name (set \"%s\" to use a randomized or \"%s\" to use a randomized template on each request "+
+				"or \"%s/%s\" daily/hourly randomized) [$%s]",
+			useRandomTemplate,
+			useRandomTemplateOnEachRequest,
+			useRandomTemplateDaily,
+			useRandomTemplateHourly,
+			env.TemplateName,
 		),
 	)
 	flagSet.StringVarP(
--- a/internal/http/core/errorpage.go
+++ b/internal/http/core/errorpage.go
@ -13,10 +13,15 @@ type templatePicker interface {
 	Pick() string
 }

+type renderer interface {
+	Render(content []byte, props tpl.Properties) ([]byte, error)
+}
+
 func RespondWithErrorPage( //nolint:funlen
 	ctx *fasthttp.RequestCtx,
 	cfg *config.Config,
 	p templatePicker,
+	rdr renderer,
 	pageCode string,
 	httpCode int,
 	showRequestDetails bool,
@ -37,6 +42,8 @@ func RespondWithErrorPage( //nolint:funlen
 		props.ServiceName = string(ctx.Request.Header.Peek(ServiceName))
 		props.ServicePort = string(ctx.Request.Header.Peek(ServicePort))
 		props.RequestID = string(ctx.Request.Header.Peek(RequestID))
+		props.ForwardedFor = string(ctx.Request.Header.Peek(ForwardedFor))
+		props.Host = string(ctx.Request.Header.Peek(Host))
 	}

 	if page, exists := cfg.Pages[pageCode]; exists {
@ -62,7 +69,7 @@ func RespondWithErrorPage( //nolint:funlen
 		{
 			SetClientFormat(ctx, JSONContentType)

-			if content, err := tpl.Render(json.Content(), props); err == nil {
+			if content, err := rdr.Render(json.Content(), props); err == nil {
 				ctx.SetStatusCode(httpCode)
 				_, _ = ctx.Write(content)
 			} else {
@ -75,7 +82,7 @@ func RespondWithErrorPage( //nolint:funlen
 		{
 			SetClientFormat(ctx, XMLContentType)

-			if content, err := tpl.Render(xml.Content(), props); err == nil {
+			if content, err := rdr.Render(xml.Content(), props); err == nil {
 				ctx.SetStatusCode(httpCode)
 				_, _ = ctx.Write(content)
 			} else {
@ -91,7 +98,7 @@ func RespondWithErrorPage( //nolint:funlen
 			var templateName = p.Pick()

 			if template, exists := cfg.Template(templateName); exists {
-				if content, err := tpl.Render(template.Content(), props); err == nil {
+				if content, err := rdr.Render(template.Content(), props); err == nil {
 					ctx.SetStatusCode(httpCode)
 					_, _ = ctx.Write(content)
 				} else {
--- a/internal/http/core/headers.go
+++ b/internal/http/core/headers.go
@ -24,4 +24,10 @@ const (

 	// RequestID is a unique ID that identifies the request - same as for backend service
 	RequestID = "X-Request-ID"
+
+	// ForwardedFor identifies the user of this session
+	ForwardedFor = "X-Forwarded-For"
+
+	// Host identifies the hosts origin
+	Host = "Host"
 )
--- a/internal/http/handlers/errorpage/handler.go
+++ b/internal/http/handlers/errorpage/handler.go
@ -3,21 +3,28 @@ package errorpage
 import (
 	"github.com/tarampampam/error-pages/internal/config"
 	"github.com/tarampampam/error-pages/internal/http/core"
+	"github.com/tarampampam/error-pages/internal/tpl"
 	"github.com/valyala/fasthttp"
 )

-type templatePicker interface {
-	// Pick the template name for responding.
-	Pick() string
-}
+type (
+	templatePicker interface {
+		// Pick the template name for responding.
+		Pick() string
+	}
+
+	renderer interface {
+		Render(content []byte, props tpl.Properties) ([]byte, error)
+	}
+)

 // NewHandler creates handler for error pages serving.
-func NewHandler(cfg *config.Config, p templatePicker, showRequestDetails bool) fasthttp.RequestHandler {
+func NewHandler(cfg *config.Config, p templatePicker, rdr renderer, showRequestDetails bool) fasthttp.RequestHandler {
 	return func(ctx *fasthttp.RequestCtx) {
 		core.SetClientFormat(ctx, core.PlainTextContentType) // default content type

 		if code, ok := ctx.UserValue("code").(string); ok {
-			core.RespondWithErrorPage(ctx, cfg, p, code, fasthttp.StatusOK, showRequestDetails)
+			core.RespondWithErrorPage(ctx, cfg, p, rdr, code, fasthttp.StatusOK, showRequestDetails)
 		} else { // will never occur
 			ctx.SetStatusCode(fasthttp.StatusInternalServerError)
 			_, _ = ctx.WriteString("cannot extract requested code from the request")
--- a/internal/http/handlers/index/handler.go
+++ b/internal/http/handlers/index/handler.go
@ -5,6 +5,7 @@ import (

 	"github.com/tarampampam/error-pages/internal/config"
 	"github.com/tarampampam/error-pages/internal/http/core"
+	"github.com/tarampampam/error-pages/internal/tpl"
 	"github.com/valyala/fasthttp"
 )

@ -13,12 +14,17 @@ type (
 		// Pick the template name for responding.
 		Pick() string
 	}
+
+	renderer interface {
+		Render(content []byte, props tpl.Properties) ([]byte, error)
+	}
 )

 // NewHandler creates handler for the index page serving.
 func NewHandler(
 	cfg *config.Config,
 	p templatePicker,
+	rdr renderer,
 	defaultPageCode string,
 	defaultHTTPCode uint16,
 	showRequestDetails bool,
@ -30,7 +36,7 @@ func NewHandler(
 			pageCode, httpCode = strconv.Itoa(returnCode), returnCode
 		}

-		core.RespondWithErrorPage(ctx, cfg, p, pageCode, httpCode, showRequestDetails)
+		core.RespondWithErrorPage(ctx, cfg, p, rdr, pageCode, httpCode, showRequestDetails)
 	}
 }

--- a/internal/http/server.go
+++ b/internal/http/server.go
@ -15,6 +15,7 @@ import (
 	notfoundHandler "github.com/tarampampam/error-pages/internal/http/handlers/notfound"
 	versionHandler "github.com/tarampampam/error-pages/internal/http/handlers/version"
 	"github.com/tarampampam/error-pages/internal/metrics"
+	"github.com/tarampampam/error-pages/internal/tpl"
 	"github.com/tarampampam/error-pages/internal/version"
 	"github.com/valyala/fasthttp"
 	"go.uber.org/zap"
@ -24,6 +25,7 @@ type Server struct {
 	log    *zap.Logger
 	fast   *fasthttp.Server
 	router *router.Router
+	rdr    *tpl.TemplateRenderer
 }

 const (
@ -33,6 +35,8 @@ const (
 )

 func NewServer(log *zap.Logger) Server {
+	rdr := tpl.NewTemplateRenderer()
+
 	return Server{
 		// fasthttp docs: <https://github.com/valyala/fasthttp>
 		fast: &fasthttp.Server{
@ -46,6 +50,7 @@ func NewServer(log *zap.Logger) Server {
 		},
 		router: router.New(),
 		log:    log,
+		rdr:    rdr,
 	}
 }

@ -76,8 +81,8 @@ func (s *Server) Register(

 	s.fast.Handler = common.DurationMetrics(common.LogRequest(s.router.Handler, s.log), &m)

-	s.router.GET("/", indexHandler.NewHandler(cfg, templatePicker, defaultPageCode, defaultHTTPCode, showDetails))
-	s.router.GET("/{code}.html", errorpageHandler.NewHandler(cfg, templatePicker, showDetails))
+	s.router.GET("/", indexHandler.NewHandler(cfg, templatePicker, s.rdr, defaultPageCode, defaultHTTPCode, showDetails)) //nolint:lll
+	s.router.GET("/{code}.html", errorpageHandler.NewHandler(cfg, templatePicker, s.rdr, showDetails))
 	s.router.GET("/version", versionHandler.NewHandler(version.Version()))

 	liveHandler := healthzHandler.NewHandler(checkers.NewLiveChecker())
@ -92,4 +97,12 @@ func (s *Server) Register(
 }

 // Stop server.
-func (s *Server) Stop() error { return s.fast.Shutdown() }
+func (s *Server) Stop() error {
+	if err := s.rdr.Close(); err != nil {
+		defer func() { _ = s.fast.Shutdown() }()
+
+		return err
+	}
+
+	return s.fast.Shutdown()
+}
--- a/internal/pick/picker.go
+++ b/internal/pick/picker.go
@ -51,33 +51,38 @@ func (p *picker) NextIndex() uint32 {

 	case RandomOnce:
 		if p.lastIdx == unsetIdx {
-			p.mu.Lock()
-			defer p.mu.Unlock()
-
-			p.lastIdx = uint32(p.rand.Intn(int(p.maxIdx)))
+			return p.randomizeNext()
 		}

 		return p.lastIdx

 	case RandomEveryTime:
-		var idx = uint32(p.rand.Intn(int(p.maxIdx + 1)))
-
-		p.mu.Lock()
-		defer p.mu.Unlock()
-
-		if idx == p.lastIdx {
-			p.lastIdx++
-		} else {
-			p.lastIdx = idx
-		}
-
-		if p.lastIdx > p.maxIdx { // overflow?
-			p.lastIdx = 0
-		}
-
-		return p.lastIdx
+		return p.randomizeNext()

 	default:
 		panic("picker.NextIndex(): unsupported mode")
 	}
 }
+
+func (p *picker) randomizeNext() uint32 {
+	var idx = uint32(p.rand.Intn(int(p.maxIdx + 1)))
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if idx == p.lastIdx {
+		p.lastIdx++
+	} else {
+		p.lastIdx = idx
+	}
+
+	if p.lastIdx > p.maxIdx { // overflow?
+		p.lastIdx = 0
+	}
+
+	if p.lastIdx == unsetIdx {
+		p.lastIdx--
+	}
+
+	return p.lastIdx
+}
--- a/internal/pick/strings_slice.go
+++ b/internal/pick/strings_slice.go
@ -1,5 +1,11 @@
 package pick

+import (
+	"errors"
+	"sync"
+	"time"
+)
+
 type StringsSlice struct {
 	s []string
 	p *picker
@ -7,7 +13,13 @@ type StringsSlice struct {

 // NewStringsSlice creates new StringsSlice.
 func NewStringsSlice(items []string, mode pickMode) *StringsSlice {
-	return &StringsSlice{s: items, p: NewPicker(uint32(len(items)-1), mode)}
+	maxIdx := len(items) - 1
+
+	if maxIdx < 0 {
+		maxIdx = 0
+	}
+
+	return &StringsSlice{s: items, p: NewPicker(uint32(maxIdx), mode)}
 }

 // Pick an element from the strings slice.
@ -18,3 +30,106 @@ func (s *StringsSlice) Pick() string {

 	return s.s[s.p.NextIndex()]
 }
+
+type StringsSliceWithInterval struct {
+	s []string
+	p *picker
+	d time.Duration
+
+	idxMu sync.RWMutex
+	idx   uint32
+
+	close    chan struct{}
+	closedMu sync.RWMutex
+	closed   bool
+}
+
+// NewStringsSliceWithInterval creates new StringsSliceWithInterval.
+func NewStringsSliceWithInterval(items []string, mode pickMode, interval time.Duration) *StringsSliceWithInterval {
+	maxIdx := len(items) - 1
+
+	if maxIdx < 0 {
+		maxIdx = 0
+	}
+
+	if interval <= time.Duration(0) {
+		panic("NewStringsSliceWithInterval: wrong interval")
+	}
+
+	s := &StringsSliceWithInterval{
+		s:     items,
+		p:     NewPicker(uint32(maxIdx), mode),
+		d:     interval,
+		close: make(chan struct{}, 1),
+	}
+
+	s.next()
+
+	go s.rotate()
+
+	return s
+}
+
+func (s *StringsSliceWithInterval) rotate() {
+	defer close(s.close)
+
+	timer := time.NewTimer(s.d)
+	defer timer.Stop()
+
+	for {
+		select {
+		case <-s.close:
+			return
+
+		case <-timer.C:
+			s.next()
+			timer.Reset(s.d)
+		}
+	}
+}
+
+func (s *StringsSliceWithInterval) next() {
+	idx := s.p.NextIndex()
+
+	s.idxMu.Lock()
+	s.idx = idx
+	s.idxMu.Unlock()
+}
+
+// Pick an element from the strings slice.
+func (s *StringsSliceWithInterval) Pick() string {
+	if s.isClosed() {
+		panic("StringsSliceWithInterval.Pick(): closed")
+	}
+
+	if len(s.s) == 0 {
+		return ""
+	}
+
+	s.idxMu.RLock()
+	defer s.idxMu.RUnlock()
+
+	return s.s[s.idx]
+}
+
+func (s *StringsSliceWithInterval) isClosed() (closed bool) {
+	s.closedMu.RLock()
+	closed = s.closed
+	s.closedMu.RUnlock()
+
+	return
+}
+
+func (s *StringsSliceWithInterval) Close() error {
+	if s.isClosed() {
+		return errors.New("closed")
+	}
+
+	s.closedMu.Lock()
+	s.closed = true
+	s.closedMu.Unlock()
+
+	s.close <- struct{}{}
+
+	return nil
+}
--- a/internal/pick/strings_slice_test.go
+++ b/internal/pick/strings_slice_test.go
@ -2,6 +2,7 @@ package pick_test

 import (
 	"testing"
+	"time"

 	"github.com/stretchr/testify/assert"
 	"github.com/tarampampam/error-pages/internal/pick"
@ -47,3 +48,83 @@ func TestStringsSlice_Pick(t *testing.T) {
 		}
 	})
 }
+
+func TestNewStringsSliceWithInterval_Pick(t *testing.T) {
+	t.Run("first", func(t *testing.T) {
+		for i := uint8(0); i < 50; i++ {
+			p := pick.NewStringsSliceWithInterval([]string{}, pick.First, time.Millisecond)
+			assert.Equal(t, "", p.Pick())
+			assert.NoError(t, p.Close())
+			assert.Panics(t, func() { p.Pick() })
+		}
+
+		p := pick.NewStringsSliceWithInterval([]string{"foo", "bar", "baz"}, pick.First, time.Millisecond)
+
+		for i := uint8(0); i < 50; i++ {
+			assert.Equal(t, "foo", p.Pick())
+
+			<-time.After(time.Millisecond * 2)
+		}
+
+		assert.NoError(t, p.Close())
+		assert.Error(t, p.Close())
+		assert.Panics(t, func() { p.Pick() })
+	})
+
+	t.Run("random once", func(t *testing.T) {
+		for i := uint8(0); i < 50; i++ {
+			p := pick.NewStringsSliceWithInterval([]string{}, pick.RandomOnce, time.Millisecond)
+			assert.Equal(t, "", p.Pick())
+			assert.NoError(t, p.Close())
+			assert.Panics(t, func() { p.Pick() })
+		}
+
+		var (
+			p      = pick.NewStringsSliceWithInterval([]string{"foo", "bar", "baz"}, pick.RandomOnce, time.Millisecond)
+			picked = p.Pick()
+		)
+
+		for i := uint8(0); i < 50; i++ {
+			assert.Equal(t, picked, p.Pick())
+
+			<-time.After(time.Millisecond * 2)
+		}
+
+		assert.NoError(t, p.Close())
+		assert.Error(t, p.Close())
+		assert.Panics(t, func() { p.Pick() })
+	})
+
+	t.Run("random every time", func(t *testing.T) {
+		for i := uint8(0); i < 50; i++ {
+			p := pick.NewStringsSliceWithInterval([]string{}, pick.RandomEveryTime, time.Millisecond)
+			assert.Equal(t, "", p.Pick())
+			assert.NoError(t, p.Close())
+			assert.Panics(t, func() { p.Pick() })
+		}
+
+		var changed int
+
+		for i := uint8(0); i < 50; i++ {
+			p := pick.NewStringsSliceWithInterval([]string{"foo", "bar", "baz"}, pick.RandomEveryTime, time.Millisecond) //nolint:lll
+
+			one, two := p.Pick(), p.Pick()
+			assert.Equal(t, one, two)
+
+			<-time.After(time.Millisecond * 2)
+
+			three, four := p.Pick(), p.Pick()
+			assert.Equal(t, three, four)
+
+			if one != three {
+				changed++
+			}
+
+			assert.NoError(t, p.Close())
+			assert.Error(t, p.Close())
+			assert.Panics(t, func() { p.Pick() })
+		}
+
+		assert.GreaterOrEqual(t, changed, 25)
+	})
+}
--- a/internal/tpl/hasher.go
+++ b/internal/tpl/hasher.go
@ -0,0 +1,25 @@
+package tpl
+
+import (
+	"bytes"
+	"crypto/md5" //nolint:gosec
+	"encoding/gob"
+)
+
+const hashLength = 16 // md5 hash length
+
+type Hash [hashLength]byte
+
+func HashStruct(s interface{}) (Hash, error) {
+	var b bytes.Buffer
+
+	if err := gob.NewEncoder(&b).Encode(s); err != nil {
+		return Hash{}, err
+	}
+
+	return md5.Sum(b.Bytes()), nil //nolint:gosec
+}
+
+func HashBytes(b []byte) Hash {
+	return md5.Sum(b) //nolint:gosec
+}
--- a/internal/tpl/hasher_test.go
+++ b/internal/tpl/hasher_test.go
@ -0,0 +1,35 @@
+package tpl_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tarampampam/error-pages/internal/tpl"
+)
+
+func TestHashBytes(t *testing.T) {
+	assert.NotEqual(t, tpl.HashBytes([]byte{1}), tpl.HashBytes([]byte{2}))
+}
+
+func TestHashStruct(t *testing.T) {
+	type s struct {
+		S string
+		I int
+		B bool
+	}
+
+	h1, err1 := tpl.HashStruct(s{S: "foo", I: 1, B: false})
+	assert.NoError(t, err1)
+
+	h2, err2 := tpl.HashStruct(s{S: "bar", I: 2, B: true})
+	assert.NoError(t, err2)
+
+	assert.NotEqual(t, h1, h2)
+
+	type p struct { // no exported fields
+		any string
+	}
+
+	_, err := tpl.HashStruct(p{any: "foo"})
+	assert.Error(t, err)
+}
--- a/internal/tpl/properties.go
+++ b/internal/tpl/properties.go
@ -1,6 +1,8 @@
 package tpl

-import "reflect"
+import (
+	"reflect"
+)

 type Properties struct { // only string properties with a "token" tag, please
 	Code               string `token:"code"`
@ -12,6 +14,8 @@ type Properties struct { // only string properties with a "token" tag, please
 	ServiceName        string `token:"service_name"`
 	ServicePort        string `token:"service_port"`
 	RequestID          string `token:"request_id"`
+	ForwardedFor       string `token:"forwarded_for"`
+	Host               string `token:"host"`
 	ShowRequestDetails bool
 }

@ -31,3 +35,5 @@ func (p *Properties) Replaces() map[string]string {

 	return replaces
 }
+
+func (p *Properties) Hash() (Hash, error) { return HashStruct(p) }
--- a/internal/tpl/properties_test.go
+++ b/internal/tpl/properties_test.go
@ -9,15 +9,17 @@ import (

 func TestProperties_Replaces(t *testing.T) {
 	props := tpl.Properties{
-		Code:        "foo",
-		Message:     "bar",
-		Description: "baz",
-		OriginalURI: "aaa",
-		Namespace:   "bbb",
-		IngressName: "ccc",
-		ServiceName: "ddd",
-		ServicePort: "eee",
-		RequestID:   "fff",
+		Code:         "foo",
+		Message:      "bar",
+		Description:  "baz",
+		OriginalURI:  "aaa",
+		Namespace:    "bbb",
+		IngressName:  "ccc",
+		ServiceName:  "ddd",
+		ServicePort:  "eee",
+		RequestID:    "fff",
+		ForwardedFor: "ggg",
+		Host:         "hhh",
 	}

 	r := props.Replaces()
@ -31,6 +33,8 @@ func TestProperties_Replaces(t *testing.T) {
 	assert.Equal(t, "ddd", r["service_name"])
 	assert.Equal(t, "eee", r["service_port"])
 	assert.Equal(t, "fff", r["request_id"])
+	assert.Equal(t, "ggg", r["forwarded_for"])
+	assert.Equal(t, "hhh", r["host"])

 	props.Code, props.Message, props.Description = "", "", ""

@ -40,3 +44,23 @@ func TestProperties_Replaces(t *testing.T) {
 	assert.Equal(t, "", r["message"])
 	assert.Equal(t, "", r["description"])
 }
+
+func TestProperties_Hash(t *testing.T) {
+	props1 := tpl.Properties{Code: "123"}
+	props2 := tpl.Properties{Code: "123"}
+
+	hash1, err := props1.Hash()
+	assert.NoError(t, err)
+
+	hash2, err := props2.Hash()
+	assert.NoError(t, err)
+
+	assert.Equal(t, hash1, hash2)
+
+	props2.Code = "321"
+
+	hash2, err = props2.Hash()
+	assert.NoError(t, err)
+
+	assert.NotEqual(t, hash1, hash2)
+}
--- a/internal/tpl/render.go
+++ b/internal/tpl/render.go
@ -5,13 +5,16 @@ import (
 	"encoding/json"
 	"os"
 	"strconv"
+	"sync"
 	"text/template"
 	"time"

+	"github.com/pkg/errors"
 	"github.com/tarampampam/error-pages/internal/version"
 )

-var tplFnMap = template.FuncMap{ //nolint:gochecknoglobals // these functions can be used in templates
+// These functions are always allowed in the templates.
+var tplFnMap = template.FuncMap{ //nolint:gochecknoglobals
 	"now":      time.Now,
 	"hostname": os.Hostname,
 	"json":     func(v interface{}) string { b, _ := json.Marshal(v); return string(b) }, //nolint:nlreturn
@ -29,11 +32,113 @@ var tplFnMap = template.FuncMap{ //nolint:gochecknoglobals // these functions ca
 	},
 }

-func Render(content []byte, props Properties) ([]byte, error) {
+var ErrClosed = errors.New("closed")
+
+type TemplateRenderer struct {
+	cacheMu sync.RWMutex
+	cache   map[cacheEntryHash]cacheItem // map key is a unique hash
+
+	cacheCleanupInterval time.Duration
+	cacheItemLifetime    time.Duration
+
+	close    chan struct{}
+	closedMu sync.RWMutex
+	closed   bool
+}
+
+type (
+	cacheEntryHash = [hashLength * 2]byte // two md5 hashes
+	cacheItem      struct {
+		data          []byte
+		expiresAtNano int64
+	}
+)
+
+const (
+	cacheCleanupInterval = time.Second
+	cacheItemLifetime    = time.Second * 2
+)
+
+// NewTemplateRenderer returns new template renderer. Don't forget to call Close() function!
+func NewTemplateRenderer() *TemplateRenderer {
+	tr := &TemplateRenderer{
+		cache:                make(map[cacheEntryHash]cacheItem),
+		cacheCleanupInterval: cacheCleanupInterval,
+		cacheItemLifetime:    cacheItemLifetime,
+		close:                make(chan struct{}, 1),
+	}
+
+	go tr.cleanup()
+
+	return tr
+}
+
+func (tr *TemplateRenderer) cleanup() {
+	defer close(tr.close)
+
+	timer := time.NewTimer(tr.cacheCleanupInterval)
+	defer timer.Stop()
+
+	for {
+		select {
+		case <-tr.close:
+			tr.cacheMu.Lock()
+			for hash := range tr.cache {
+				delete(tr.cache, hash)
+			}
+			tr.cacheMu.Unlock()
+
+			return
+
+		case <-timer.C:
+			tr.cacheMu.Lock()
+			var now = time.Now().UnixNano()
+
+			for hash, item := range tr.cache {
+				if now > item.expiresAtNano {
+					delete(tr.cache, hash)
+				}
+			}
+			tr.cacheMu.Unlock()
+
+			timer.Reset(tr.cacheCleanupInterval)
+		}
+	}
+}
+
+func (tr *TemplateRenderer) Render(content []byte, props Properties) ([]byte, error) { //nolint:funlen
+	if tr.isClosed() {
+		return nil, ErrClosed
+	}
+
 	if len(content) == 0 {
 		return content, nil
 	}

+	var (
+		cacheKey     cacheEntryHash
+		cacheKeyInit bool
+	)
+
+	if propsHash, err := props.Hash(); err == nil {
+		cacheKeyInit, cacheKey = true, tr.mixHashes(propsHash, HashBytes(content))
+
+		tr.cacheMu.RLock()
+		item, hit := tr.cache[cacheKey]
+		tr.cacheMu.RUnlock()
+
+		if hit {
+			// cache item has been expired?
+			if time.Now().UnixNano() > item.expiresAtNano {
+				tr.cacheMu.Lock()
+				delete(tr.cache, cacheKey)
+				tr.cacheMu.Unlock()
+			} else {
+				return item.data, nil
+			}
+		}
+	}
+
 	var funcMap = template.FuncMap{
 		"show_details": func() bool { return props.ShowRequestDetails },
 		"hide_details": func() bool { return !props.ShowRequestDetails },
@ -62,5 +167,50 @@ func Render(content []byte, props Properties) ([]byte, error) {
 		return nil, err
 	}

-	return buf.Bytes(), nil
+	b := buf.Bytes()
+
+	if cacheKeyInit {
+		tr.cacheMu.Lock()
+		tr.cache[cacheKey] = cacheItem{
+			data:          b,
+			expiresAtNano: time.Now().UnixNano() + tr.cacheItemLifetime.Nanoseconds(),
+		}
+		tr.cacheMu.Unlock()
+	}
+
+	return b, nil
+}
+
+func (tr *TemplateRenderer) isClosed() (closed bool) {
+	tr.closedMu.RLock()
+	closed = tr.closed
+	tr.closedMu.RUnlock()
+
+	return
+}
+
+func (tr *TemplateRenderer) Close() error {
+	if tr.isClosed() {
+		return ErrClosed
+	}
+
+	tr.closedMu.Lock()
+	tr.closed = true
+	tr.closedMu.Unlock()
+
+	tr.close <- struct{}{}
+
+	return nil
+}
+
+func (tr *TemplateRenderer) mixHashes(a, b Hash) (result cacheEntryHash) {
+	for i := 0; i < len(a); i++ {
+		result[i] = a[i]
+	}
+
+	for i := 0; i < len(b); i++ {
+		result[i+len(a)] = b[i]
+	}
+
+	return
 }
--- a/internal/tpl/render_test.go
+++ b/internal/tpl/render_test.go
@ -1,6 +1,9 @@
 package tpl_test

 import (
+	"math/rand"
+	"strconv"
+	"sync"
 	"testing"

 	"github.com/stretchr/testify/assert"
@ -8,6 +11,9 @@ import (
 )

 func Test_Render(t *testing.T) {
+	renderer := tpl.NewTemplateRenderer()
+	defer func() { _ = renderer.Close() }()
+
 	for name, tt := range map[string]struct {
 		giveContent string
 		giveProps   tpl.Properties
@ -52,7 +58,7 @@ func Test_Render(t *testing.T) {
 		},
 	} {
 		t.Run(name, func(t *testing.T) {
-			content, err := tpl.Render([]byte(tt.giveContent), tt.giveProps)
+			content, err := renderer.Render([]byte(tt.giveContent), tt.giveProps)

 			if tt.wantError == true {
 				assert.Error(t, err)
@ -64,11 +70,48 @@ func Test_Render(t *testing.T) {
 	}
 }

+func TestTemplateRenderer_Render_Concurrent(t *testing.T) {
+	renderer := tpl.NewTemplateRenderer()
+
+	var wg sync.WaitGroup
+
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+
+		go func() {
+			defer wg.Done()
+
+			props := tpl.Properties{
+				Code:        strconv.Itoa(rand.Intn(599-300+1) + 300), //nolint:gosec
+				Message:     "Not found",
+				Description: "Blah",
+			}
+
+			content, err := renderer.Render([]byte("{{code}}: {{ message }} {{description}}"), props)
+
+			assert.NoError(t, err)
+			assert.NotEmpty(t, content)
+		}()
+	}
+
+	wg.Wait()
+
+	assert.NoError(t, renderer.Close())
+	assert.EqualError(t, renderer.Close(), tpl.ErrClosed.Error())
+
+	content, err := renderer.Render([]byte{}, tpl.Properties{})
+	assert.Nil(t, content)
+	assert.EqualError(t, err, tpl.ErrClosed.Error())
+}
+
 func BenchmarkRenderHTML(b *testing.B) {
 	b.ReportAllocs()

+	renderer := tpl.NewTemplateRenderer()
+	defer func() { _ = renderer.Close() }()
+
 	for i := 0; i < b.N; i++ {
-		_, _ = tpl.Render(
+		_, _ = renderer.Render(
 			[]byte("{{code}}: {{ message }} {{description}}"),
 			tpl.Properties{Code: "404", Message: "Not found", Description: "Blah"},
 		)
--- a/templates/cats.html
+++ b/templates/cats.html
@ -62,10 +62,18 @@
        {{ if show_details }}
        <div class="details">
            <table>
+                {{- if host }}<tr>
+                    <td class="name">Host</td>
+                    <td class="value">{{ host }}</td>
+                </tr>{{ end -}}
                {{- if original_uri }}<tr>
                    <td class="name">Original URI</td>
                    <td class="value">{{ original_uri }}</td>
                </tr>{{ end -}}
+                {{- if forwarded_for }}<tr>
+                    <td class="name">Forwarded for</td>
+                    <td class="value">{{ forwarded_for }}</td>
+                </tr>{{ end -}}
                {{- if namespace }}<tr>
                    <td class="name">Namespace</td>
                    <td class="value">{{ namespace }}</td>
--- a/templates/ghost.html
+++ b/templates/ghost.html
@ -55,10 +55,18 @@
        {{ if show_details }}
        <div class="details">
            <table>
+                {{- if host }}<tr>
+                    <td class="name">Host</td>
+                    <td class="value">{{ host }}</td>
+                </tr>{{ end -}}
                {{- if original_uri }}<tr>
                    <td class="name">Original URI</td>
                    <td class="value">{{ original_uri }}</td>
                </tr>{{ end -}}
+                {{- if forwarded_for }}<tr>
+                    <td class="name">Forwarded for</td>
+                    <td class="value">{{ forwarded_for }}</td>
+                </tr>{{ end -}}
                {{- if namespace }}<tr>
                    <td class="name">Namespace</td>
                    <td class="value">{{ namespace }}</td>
--- a/templates/hacker-terminal.html
+++ b/templates/hacker-terminal.html
@ -150,7 +150,9 @@
    <p class="output">Good luck.</p>
    {{ if show_details }}
    <div class="details">
+        {{- if host }}<p class="output small">Host: <code>{{ host }}</code></p>{{ end -}}
        {{- if original_uri }}<p class="output small">Original URI: <code>{{ original_uri }}</code></p>{{ end -}}
+        {{- if forwarded_for }}<p class="output small">Forwarded for: <code>{{ forwarded_for }}</code></p>{{ end -}}
        {{- if namespace }}<p class="output small">Namespace: <code>{{ namespace }}</code></p>{{ end -}}
        {{- if ingress_name }}<p class="output small">Ingress name: <code>{{ ingress_name }}</code></p>{{ end -}}
        {{- if service_name }}<p class="output small">Service name: <code>{{ service_name }}</code></p>{{ end -}}
--- a/templates/l7-dark.html
+++ b/templates/l7-dark.html
@ -40,10 +40,18 @@
        {{ if show_details }}
        <div class="details">
            <table>
+                {{- if host }}<tr>
+                    <td class="name">Host</td>
+                    <td class="value">{{ host }}</td>
+                </tr>{{ end -}}
                {{- if original_uri }}<tr>
                    <td class="name">Original URI</td>
                    <td class="value">{{ original_uri }}</td>
                </tr>{{ end -}}
+                {{- if forwarded_for }}<tr>
+                    <td class="name">Forwarded for</td>
+                    <td class="value">{{ forwarded_for }}</td>
+                </tr>{{ end -}}
                {{- if namespace }}<tr>
                    <td class="name">Namespace</td>
                    <td class="value">{{ namespace }}</td>
--- a/templates/l7-light.html
+++ b/templates/l7-light.html
@ -40,10 +40,18 @@
        {{ if show_details }}
        <div class="details">
            <table>
+                {{- if host }}<tr>
+                    <td class="name">Host</td>
+                    <td class="value">{{ host }}</td>
+                </tr>{{ end -}}
                {{- if original_uri }}<tr>
                    <td class="name">Original URI</td>
                    <td class="value">{{ original_uri }}</td>
                </tr>{{ end -}}
+                {{- if forwarded_for }}<tr>
+                    <td class="name">Forwarded for</td>
+                    <td class="value">{{ forwarded_for }}</td>
+                </tr>{{ end -}}
                {{- if namespace }}<tr>
                    <td class="name">Namespace</td>
                    <td class="value">{{ namespace }}</td>
--- a/templates/noise.html
+++ b/templates/noise.html
@ -3,7 +3,9 @@
    Error {{ code }}: {{ message }}
    Description: {{ description }}
 {{ if show_details }}
+    {{ if host }}Host: {{ host }}{{ end }}
    {{ if original_uri }}Original URI: {{ original_uri }}{{ end }}
+    {{ if forwarded_for }}Forwarded for: {{ forwarded_for }}{{ end }}
    {{ if namespace }}Namespace: {{ namespace }}{{ end }}
    {{ if ingress_name }}Ingress name: {{ ingress_name }}{{ end }}
    {{ if service_name }}Service name: {{ service_name }}{{ end }}
--- a/templates/readme.md
+++ b/templates/readme.md
@ -1 +1,37 @@
-# TODO: Write docs
+# Templates
+
+Creating templates is a very simple operation, even for those who know nothing at all about [Go Template](https://pkg.go.dev/text/template). All you should know is:
+
+- The template should be one page. Without additional `css` or `js` files (but you can load them from the CDN or another GitHub repositories using [jsdelivr.com](https://www.jsdelivr.com/), for example)
+- Don't forget to include `<meta name="robots" content="noindex, nofollow" />` tag in the header
+- You can use a special "placeholders" (wrapped in `{{` and `}}`) for the rendering error code, message and others (see details below)
+
+## Supported signatures
+
+### Error page & request data
+
+| Signature                           | Description                                                   | Example                                      |
+|-------------------------------------|---------------------------------------------------------------|----------------------------------------------|
+| `{{ code }}`                        | Error page code                                               | `404`                                        |
+| `{{ message }}`                     | Error code message                                            | `Not found`                                  |
+| `{{ description }}`                 | Error code description                                        | `The server can not find the requested page` |
+| `{{ original_uri }}`                | `X-Original-URI` header value                                 | `/foo1/bar2`                                 |
+| `{{ namespace }}`                   | `X-Namespace` header value                                    | `foo`                                        |
+| `{{ ingress_name }}`                | `X-Ingress-Name` header value                                 | `bar`                                        |
+| `{{ service_name }}`                | `X-Service-Name` header value                                 | `baz`                                        |
+| `{{ service_port }}`                | `X-Service-Port` header value                                 | `8080`                                       |
+| `{{ request_id }}`                  | `X-Request-ID` header value                                   | `12AB34CD56EF78`                             |
+| `{{ forwarded_for }}`               | `X-Forwarded-For` header value                                | `203.0.113.195, 70.41.3.18`                  |
+| `{{ host }}`                        | `Host` header value                                           | `example.com`                                |
+| `{{ now.Unix }}`                    | Current timestamp (e.g. in Unix format)                       | `1643621927`                                 |
+| `{{ hostname }}`                    | OS hostname                                                   | `ab12cd34ef56`                               |
+| `{{ version }}`                     | Application version                                           | `2.5.0`                                      |
+| `{{ if show_details }}...{{ end }}` | Logical operator (server started with "show details" option?) |                                              |
+| `{{ if hide_details }}...{{ end }}` | Same as above, but inverted                                   |                                              |
+
+### Modifiers
+
+| Signature                          | Description                    | Example                             |
+|------------------------------------|--------------------------------|-------------------------------------|
+| <code>{{ ... &#124; json }}</code> | Convert value into json-string | <code>{{ code &#124; json }}</code> |
+| <code>{{ ... &#124; int }}</code>  | Convert value into integer     | <code>{{ code &#124; int }}</code>  |
--- a/templates/shuffle.html
+++ b/templates/shuffle.html
@ -76,12 +76,24 @@
        {{ if show_details }}
        <div class="hidden" id="details">
            <table>
+                {{- if host }}
+                <tr>
+                    <td class="name">Host:</td>
+                    <td class="value">{{ host }}</td>
+                </tr>
+                {{ end -}}
                {{- if original_uri }}
                <tr>
                    <td class="name">Original URI:</td>
                    <td class="value">{{ original_uri }}</td>
                </tr>
                {{ end -}}
+                {{- if forwarded_for }}
+                <tr>
+                    <td class="name">Forwarded for:</td>
+                    <td class="value">{{ forwarded_for }}</td>
+                </tr>
+                {{ end -}}
                {{- if namespace }}
                <tr>
                    <td class="name">Namespace:</td>
--- a/test/hurl/code_502_json.hurl
+++ b/test/hurl/code_502_json.hurl
@ -7,6 +7,8 @@ X-Ingress-Name: baz
 X-Service-Name: aaa
 X-Service-Port: bbb
 X-Request-ID: ccc
+X-Forwarded-For: ddd
+Host: eee

 HTTP/* 200

@ -23,6 +25,8 @@ jsonpath "$.details.ingress_name" == "baz"
 jsonpath "$.details.service_name" == "aaa"
 jsonpath "$.details.service_port" == "bbb"
 jsonpath "$.details.request_id" == "ccc"
+jsonpath "$.details.forwarded_for" == "ddd"
+jsonpath "$.details.host" == "eee"
 jsonpath "$.details.timestamp" isInteger

 # X-Format in the action
--- a/test/hurl/code_502_xml.hurl
+++ b/test/hurl/code_502_xml.hurl
@ -7,6 +7,8 @@ X-Ingress-Name: baz
 X-Service-Name: aaa
 X-Service-Port: bbb
 X-Request-ID: ccc
+X-Forwarded-For: ddd
+Host: eee

 HTTP/* 200

@ -22,6 +24,8 @@ xpath "string(//error/details/ingressName)" == "baz"
 xpath "string(//error/details/serviceName)" == "aaa"
 xpath "string(//error/details/servicePort)" == "bbb"
 xpath "string(//error/details/requestID)" == "ccc"
+xpath "string(//error/details/forwardedFor)" == "ddd"
+xpath "string(//error/details/host)" == "eee"
 xpath "string(//error/details/timestamp)" exists

 # X-Format in the action
--- a/test/wrk/request.lua
+++ b/test/wrk/request.lua
@ -0,0 +1,9 @@
+local formats = { 'application/json', 'application/xml', 'text/html', 'text/plain' }
+
+request = function()
+    wrk.headers["X-Namespace"] = "NAMESPACE_" .. tostring(math.random(0, 99999999))
+    wrk.headers["X-Request-ID"] = "REQ_ID_" .. tostring(math.random(0, 99999999))
+    wrk.headers["Content-Type"] = formats[ math.random( 0, #formats - 1 ) ]
+
+    return wrk.format("GET", "/500.html?rnd=" .. tostring(math.random(0, 99999999)), nil, nil)
+end
Author	SHA1	Message	Date
Paramtamtam	22d3e3485e	Changelog updated	2022-02-01 20:12:11 +05:00
Paramtamtam	375272b561	Change themes in random order once a day/hour (#62 )	2022-02-01 19:39:50 +05:00
Paramtamtam	7e7f956fae	template docs added	2022-01-31 14:45:12 +05:00
Paramtamtam	d672112cc2	Changelog updated	2022-01-31 13:53:06 +05:00
Paramtamtam	32b92611a7	small fixes	2022-01-31 13:45:22 +05:00
Paramtamtam	cc6cbc7d47	Template rendering performance issue has been fixed (#60 )	2022-01-31 13:43:40 +05:00
Paramtamtam	690a405994	fix the template	2022-01-31 10:53:51 +05:00
Paramtamtam	f72c2b85fd	Changes after merging	2022-01-31 10:46:51 +05:00
Florian Michel	42523ae9d9	Adds "Host" and "X-Forwarded-For" header options (#61 )	2022-01-31 10:40:58 +05:00
dependabot[bot]	da2dc5c63a	Bump github.com/fasthttp/router from 1.4.4 to 1.4.5 (#59 )	2022-01-29 07:50:34 +00:00
dependabot[bot]	a0a1d3caca	Bump go.uber.org/zap from 1.19.1 to 1.20.0 (#58 )	2022-01-29 07:50:31 +00:00
dependabot[bot]	915e810088	Bump golang from 1.17.5-alpine to 1.17.6-alpine (#57 )	2022-01-29 07:50:17 +00:00
dependabot[bot]	00c139b525	Bump github.com/valyala/fasthttp from 1.31.0 to 1.33.0 (#56 )	2022-01-29 07:46:47 +00:00
Paramtamtam	eca99eb569	Readme file updated	2022-01-29 01:14:06 +05:00
Paramtamtam	dfaeea7483	Readme file updated	2022-01-29 01:12:36 +05:00
Paramtamtam	f71b07f647	fix typos	2022-01-29 01:11:44 +05:00