wip: 🔕 temporary commit

internal/cli/serve/command.go

@@ -39,8 +39,9 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 	var (
 		addrFlag       = shared.ListenAddrFlag
 		portFlag       = shared.ListenPortFlag
-		addTplFlag     = shared.AddTemplateFlag
-		addCodeFlag    = shared.AddHTTPCodeFlag
+		addTplFlag     = shared.AddTemplatesFlag
+		disableTplFlag = shared.DisableTemplateNamesFlag
+		addCodeFlag    = shared.AddHTTPCodesFlag
 		jsonFormatFlag = cli.StringFlag{
 			Name:     "json-format",
 			Usage:    "override the default error page response in JSON format (Go templates are supported)",
@@ -140,16 +141,6 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 				return nil
 			},
 		}
-
-		// readBufferSizeFlag = cli.UintFlag{
-		//	Name: "read-buffer-size",
-		//	Usage: "customize the HTTP read buffer size (set per connection for reading requests, also limits the " +
-		//		"maximum header size; consider increasing it if your clients send multi-KB request URIs or multi-KB " +
-		//		"headers, such as large cookies)",
-		//	DefaultText: "not set",
-		//	Sources:     cli.EnvVars("READ_BUFFER_SIZE"),
-		//	OnlyOnce:    true,
-		// }
 	)
 
 	cmd.c = &cli.Command{
@@ -160,16 +151,28 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 		Action: func(ctx context.Context, c *cli.Command) error {
 			cmd.opt.http.addr = c.String(addrFlag.Name)
 			cmd.opt.http.port = uint16(c.Uint(portFlag.Name))
-			// cmd.opt.http.readBufferSize = uint(c.Uint(readBufferSizeFlag.Name))
-
-			cfg.TemplateName = c.String(templateNameFlag.Name)
 			cfg.L10n.Disable = c.Bool(disableL10nFlag.Name)
 			cfg.DefaultCodeToRender = uint16(c.Uint(defaultCodeToRenderFlag.Name))
 			cfg.RespondWithSameHTTPCode = c.Bool(sendSameHTTPCodeFlag.Name)
 			cfg.RotationMode, _ = config.ParseRotationMode(c.String(rotationModeFlag.Name))
 			cfg.ShowDetails = c.Bool(showDetailsFlag.Name)
 
-			if add := c.StringSlice(addTplFlag.Name); len(add) > 0 { // add templates from files to the config
+			{ // override default JSON, XML, and PlainText formats
+				if c.IsSet(jsonFormatFlag.Name) {
+					cfg.Formats.JSON = strings.TrimSpace(c.String(jsonFormatFlag.Name))
+				}
+
+				if c.IsSet(xmlFormatFlag.Name) {
+					cfg.Formats.XML = strings.TrimSpace(c.String(xmlFormatFlag.Name))
+				}
+
+				if c.IsSet(plainTextFormatFlag.Name) {
+					cfg.Formats.PlainText = strings.TrimSpace(c.String(plainTextFormatFlag.Name))
+				}
+			}
+
+			// add templates from files to the configuration
+			if add := c.StringSlice(addTplFlag.Name); len(add) > 0 {
 				for _, templatePath := range add {
 					if addedName, err := cfg.Templates.AddFromFile(templatePath); err != nil {
 						return fmt.Errorf("cannot add template from file %s: %w", templatePath, err)
@@ -182,10 +185,7 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 				}
 			}
 
-			if !cfg.Templates.Has(cfg.TemplateName) {
-				return fmt.Errorf("template %s not found and cannot be used", cfg.TemplateName)
-			}
-
+			// set the list of HTTP headers we need to proxy from the incoming request to the error page response
 			if c.IsSet(proxyHeadersListFlag.Name) {
 				var m = make(map[string]struct{}) // map is used to avoid duplicates
 
@@ -200,7 +200,8 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 				}
 			}
 
-			if add := c.StringMap(addCodeFlag.Name); len(add) > 0 { // add custom HTTP codes
+			// add custom HTTP codes to the configuration
+			if add := c.StringMap(addCodeFlag.Name); len(add) > 0 {
 				for code, msgAndDesc := range add {
 					var (
 						parts = strings.SplitN(msgAndDesc, "/", 2) //nolint:mnd
@@ -225,17 +226,24 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 				}
 			}
 
-			{ // override default JSON and XML formats
-				if c.IsSet(jsonFormatFlag.Name) {
-					cfg.Formats.JSON = strings.TrimSpace(c.String(jsonFormatFlag.Name))
+			// disable templates specified by the user
+			if disable := c.StringSlice(disableTplFlag.Name); len(disable) > 0 {
+				for _, templateName := range disable {
+					if ok := cfg.Templates.Remove(templateName); ok {
+						log.Info("Template disabled", logger.String("name", templateName))
+					}
 				}
+			}
 
-				if c.IsSet(xmlFormatFlag.Name) {
-					cfg.Formats.XML = strings.TrimSpace(c.String(xmlFormatFlag.Name))
-				}
+			// if the rotation mode is set to random-on-startup, pick a random template (ignore the user-provided
+			// template name)
+			if cfg.RotationMode == config.RotationModeRandomOnStartup {
+				cfg.TemplateName = cfg.Templates.RandomName()
+			} else { // otherwise, use the user-provided template name
+				cfg.TemplateName = c.String(templateNameFlag.Name)
 
-				if c.IsSet(plainTextFormatFlag.Name) {
-					cfg.Formats.PlainText = strings.TrimSpace(c.String(plainTextFormatFlag.Name))
+				if !cfg.Templates.Has(cfg.TemplateName) {
+					return fmt.Errorf("template %s not found and cannot be used", cfg.TemplateName)
 				}
 			}
 
@@ -244,10 +252,12 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 				logger.Strings("described HTTP codes", cfg.Codes.Codes()...),
 				logger.String("JSON format", cfg.Formats.JSON),
 				logger.String("XML format", cfg.Formats.XML),
+				logger.String("plain text format", cfg.Formats.PlainText),
 				logger.String("template name", cfg.TemplateName),
 				logger.Bool("disable localization", cfg.L10n.Disable),
 				logger.Uint16("default code to render", cfg.DefaultCodeToRender),
 				logger.Bool("respond with the same HTTP code", cfg.RespondWithSameHTTPCode),
+				logger.String("rotation mode", cfg.RotationMode.String()),
 				logger.Bool("show details", cfg.ShowDetails),
 				logger.Strings("proxy HTTP headers", cfg.ProxyHeaders...),
 			)
@@ -258,6 +268,7 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 			&addrFlag,
 			&portFlag,
 			&addTplFlag,
+			&disableTplFlag,
 			&addCodeFlag,
 			&jsonFormatFlag,
 			&xmlFormatFlag,
@@ -269,7 +280,6 @@ func NewCommand(log *logger.Logger) *cli.Command { //nolint:funlen,gocognit,gocy
 			&showDetailsFlag,
 			&proxyHeadersListFlag,
 			&rotationModeFlag,
-			// &readBufferSizeFlag,
 		},
 	}
 

internal/cli/shared/flags.go

@@ -49,7 +49,7 @@ var ListenPortFlag = cli.UintFlag{
 	},
 }
 
-var AddTemplateFlag = cli.StringSliceFlag{
+var AddTemplatesFlag = cli.StringSliceFlag{
 	Name: "add-template",
 	Usage: "to add a new template, provide the path to the file using this flag (the filename without the extension " +
 		"will be used as the template name)",
@@ -69,7 +69,13 @@ var AddTemplateFlag = cli.StringSliceFlag{
 	},
 }
 
-var AddHTTPCodeFlag = cli.StringMapFlag{
+var DisableTemplateNamesFlag = cli.StringSliceFlag{
+	Name:   "disable-template",
+	Usage:  "disable the specified template by its name",
+	Config: cli.StringConfig{TrimSpace: true},
+}
+
+var AddHTTPCodesFlag = cli.StringMapFlag{
 	Name: "add-http-code",
 	Usage: "to add a new HTTP status code, provide the code and its message/description using this flag (the format " +
 		"should be '%code%=%message%/%description%'; the code may contain a wildcard '*' to cover multiple codes at once, " +

internal/cli/shared/flags_test.go

@@ -84,10 +84,10 @@ func TestListenPortFlag(t *testing.T) {
 	}
 }
 
-func TestAddTemplateFlag(t *testing.T) {
+func TestAddTemplatesFlag(t *testing.T) {
 	t.Parallel()
 
-	var flag = shared.AddTemplateFlag
+	var flag = shared.AddTemplatesFlag
 
 	assert.Equal(t, "add-template", flag.Name)
 
@@ -108,10 +108,18 @@ func TestAddTemplateFlag(t *testing.T) {
 	}
 }
 
-func TestAddHTTPCodeFlag(t *testing.T) {
+func TestDisableTemplateNamesFlag(t *testing.T) {
 	t.Parallel()
 
-	var flag = shared.AddHTTPCodeFlag
+	var flag = shared.DisableTemplateNamesFlag
+
+	assert.Equal(t, "disable-template", flag.Name)
+}
+
+func TestAddHTTPCodesFlag(t *testing.T) {
+	t.Parallel()
+
+	var flag = shared.AddHTTPCodesFlag
 
 	assert.Equal(t, "add-http-code", flag.Name)
 

internal/config/config.go

@@ -74,7 +74,8 @@ const defaultJSONFormat string = `{
     "request_id": {{ request_id | json }},
     "timestamp": {{ now.Unix }}
   }{{ end }}
-}`
+}
+` // an empty line at the end is important for better UX
 
 const defaultXMLFormat string = `<?xml version="1.0" encoding="utf-8"?>
 <error>
@@ -92,7 +93,8 @@ const defaultXMLFormat string = `<?xml version="1.0" encoding="utf-8"?>
     <requestID>{{ request_id }}</requestID>
     <timestamp>{{ now.Unix }}</timestamp>
   </details>{{ end }}
-</error>`
+</error>
+` // an empty line at the end is important for better UX
 
 const defaultPlainTextFormat string = `Error {{ code }}: {{ message }}{{ if description }}
 {{ description }}{{ end }}{{ if show_details }}
@@ -105,7 +107,8 @@ Ingress Name: {{ ingress_name }}
 Service Name: {{ service_name }}
 Service Port: {{ service_port }}
 Request ID: {{ request_id }}
-Timestamp: {{ now.Unix }}{{ end }}`
+Timestamp: {{ now.Unix }}{{ end }}
+` // an empty line at the end is important for better UX
 
 //nolint:lll
 var defaultCodes = Codes{ //nolint:gochecknoglobals

internal/config/rotation_mode.go

@@ -12,8 +12,8 @@ const (
 	RotationModeDisabled            RotationMode = iota // do not rotate templates, default
 	RotationModeRandomOnStartup                         // pick a random template on startup
 	RotationModeRandomOnEachRequest                     // pick a random template on each request
-	RotationModeRandomDaily                             // once a day switch to a random template
 	RotationModeRandomHourly                            // once an hour switch to a random template
+	RotationModeRandomDaily                             // once a day switch to a random template
 )
 
 // String returns a human-readable representation of the rotation mode.
@@ -25,10 +25,10 @@ func (rm RotationMode) String() string {
 		return "random-on-startup"
 	case RotationModeRandomOnEachRequest:
 		return "random-on-each-request"
-	case RotationModeRandomDaily:
-		return "random-daily"
 	case RotationModeRandomHourly:
 		return "random-hourly"
+	case RotationModeRandomDaily:
+		return "random-daily"
 	}
 
 	return fmt.Sprintf("RotationMode(%d)", rm)
@@ -40,8 +40,8 @@ func RotationModes() []RotationMode {
 		RotationModeDisabled,
 		RotationModeRandomOnStartup,
 		RotationModeRandomOnEachRequest,
-		RotationModeRandomDaily,
 		RotationModeRandomHourly,
+		RotationModeRandomDaily,
 	}
 }
 
@@ -77,11 +77,11 @@ func ParseRotationMode[T string | []byte](text T) (RotationMode, error) {
 		return RotationModeRandomOnStartup, nil
 	case RotationModeRandomOnEachRequest.String():
 		return RotationModeRandomOnEachRequest, nil
-	case RotationModeRandomDaily.String():
-		return RotationModeRandomDaily, nil
 	case RotationModeRandomHourly.String():
 		return RotationModeRandomHourly, nil
+	case RotationModeRandomDaily.String():
+		return RotationModeRandomDaily, nil
 	}
 
-	return RotationMode(0), fmt.Errorf("unrecognized rotation mode: %q", mode)
+	return RotationModeDisabled, fmt.Errorf("unrecognized rotation mode: %q", mode)
 }

internal/config/rotation_mode_test.go

@@ -27,8 +27,8 @@ func TestRotationModes(t *testing.T) {
 		config.RotationModeDisabled,
 		config.RotationModeRandomOnStartup,
 		config.RotationModeRandomOnEachRequest,
-		config.RotationModeRandomDaily,
 		config.RotationModeRandomHourly,
+		config.RotationModeRandomDaily,
 	}, config.RotationModes())
 }
 
@@ -39,8 +39,8 @@ func TestRotationModeStrings(t *testing.T) {
 		"disabled",
 		"random-on-startup",
 		"random-on-each-request",
-		"random-daily",
 		"random-hourly",
+		"random-daily",
 	}, config.RotationModeStrings())
 }
 

internal/config/templates.go

@@ -81,3 +81,25 @@ func (tpl templates) Has(name string) (found bool) { _, found = tpl[name]; retur
 
 // Get returns the template content by the specified name, if it exists.
 func (tpl templates) Get(name string) (data string, ok bool) { data, ok = tpl[name]; return } //nolint:nlreturn
+
+// Remove deletes the template by the specified name.
+func (tpl templates) Remove(name string) (ok bool) {
+	if _, ok = tpl[name]; ok {
+		delete(tpl, name)
+	}
+
+	return
+}
+
+// RandomName picks a random template name. It returns an empty string if there are no templates.
+func (tpl templates) RandomName() string {
+	if len(tpl) == 0 {
+		return ""
+	}
+
+	for name := range tpl { // map iteration order is unpredictable (random) by design
+		return name
+	}
+
+	return ""
+}

internal/config/templates_test.go

@@ -39,6 +39,10 @@ func TestTemplates_Common(t *testing.T) {
 
 		assert.Equal(t, []string{"_test11", "_test99", "test"}, tpl.Names()) // sorted
 		assert.True(t, tpl.Has("_test99"))
+
+		assert.True(t, tpl.Remove("_test99"))
+		assert.False(t, tpl.Has("_test99"))
+		assert.False(t, tpl.Remove("_test99"))
 	})
 
 	t.Run("adding template without a name should fail", func(t *testing.T) {
@@ -134,3 +138,27 @@ func TestTemplates_AddFromFile(t *testing.T) {
 		})
 	}
 }
+
+func TestTemplates_RandomName(t *testing.T) {
+	t.Parallel()
+
+	var (
+		tpl = templates{"test": "content", "test2": "content", "test3": "content"}
+
+		lastName     = tpl.RandomName()
+		changedCount int
+	)
+
+	for range 1_000 {
+		var name = tpl.RandomName()
+
+		if name != lastName {
+			changedCount++
+		}
+
+		lastName = name
+	}
+
+	// I expect at least 100 different names in 1000 iterations
+	assert.True(t, changedCount > 200)
+}

internal/http/handlers/error_page/handler.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"sync/atomic"
+	"time"
 
 	"gh.tarampamp.am/error-pages/internal/config"
 	"gh.tarampamp.am/error-pages/internal/logger"
@@ -86,7 +88,6 @@ func New(cfg *config.Config, log *logger.Logger) http.Handler { //nolint:funlen,
 			tplProps.Host = r.Header.Get("Host")                    // the value of the `Host` header
 		}
 
-		// TODO: ADD SUPPORT FOR THE RANDOM TEMPLATE AND SO ON
 		// try to find the code message and description in the config and if not - use the standard status text or fallback
 		if desc, found := cfg.Codes.Find(code); found {
 			tplProps.Message = desc.Message
@@ -116,11 +117,13 @@ func New(cfg *config.Config, log *logger.Logger) http.Handler { //nolint:funlen,
 			}
 
 		case format == htmlFormat:
-			if tpl, found := cfg.Templates.Get(cfg.TemplateName); found {
+			var templateName = templateToUse(cfg)
+
+			if tpl, found := cfg.Templates.Get(templateName); found {
 				if content, err := template.Render(tpl, tplProps); err != nil {
 					write(w, log, fmt.Sprintf(
 						"<!DOCTYPE html>\n<html><body>Failed to render the HTML template %s: %s</body></html>",
-						cfg.TemplateName,
+						templateName,
 						err.Error(),
 					))
 				} else {
@@ -128,7 +131,7 @@ func New(cfg *config.Config, log *logger.Logger) http.Handler { //nolint:funlen,
 				}
 			} else {
 				write(w, log, fmt.Sprintf(
-					"<!DOCTYPE html>\n<html><body>Template %s not found and cannot be used</body></html>", cfg.TemplateName,
+					"<!DOCTYPE html>\n<html><body>Template %s not found and cannot be used</body></html>", templateName,
 				))
 			}
 
@@ -149,6 +152,54 @@ Supported formats: JSON, XML, HTML, Plain Text`)
 	})
 }
 
+var (
+	templateChangedAt atomic.Pointer[time.Time] //nolint:gochecknoglobals // the time when the theme was changed last time
+	pickedTemplate    atomic.Pointer[string]    //nolint:gochecknoglobals // the name of the randomly picked template
+)
+
+// templateToUse decides which template to use based on the rotation mode and the last time the template was changed.
+func templateToUse(cfg *config.Config) string {
+	switch rotationMode := cfg.RotationMode; rotationMode {
+	case config.RotationModeDisabled:
+		return cfg.TemplateName // not needed to do anything
+	case config.RotationModeRandomOnStartup:
+		return cfg.TemplateName // do nothing, the scope of this rotation mode is not here
+	case config.RotationModeRandomOnEachRequest:
+		return cfg.Templates.RandomName() // pick a random template on each request
+	case config.RotationModeRandomHourly, config.RotationModeRandomDaily:
+		var now, rndTemplate = time.Now(), cfg.Templates.RandomName()
+
+		if changedAt := templateChangedAt.Load(); changedAt == nil {
+			// the template was not changed yet (first request)
+			templateChangedAt.Store(&now)
+			pickedTemplate.Store(&rndTemplate)
+
+			return rndTemplate
+		} else {
+			// is it time to change the template?
+			if (rotationMode == config.RotationModeRandomHourly && changedAt.Hour() != now.Hour()) ||
+				(rotationMode == config.RotationModeRandomDaily && changedAt.Day() != now.Day()) {
+				templateChangedAt.Store(&now)
+				pickedTemplate.Store(&rndTemplate)
+
+				return rndTemplate
+			} else if lastUsed := pickedTemplate.Load(); lastUsed != nil {
+				// time to change the template has not come yet, so use the last picked template
+				return *lastUsed
+			} else {
+				// in case if the last picked template is not set, pick a random one and store it
+				templateChangedAt.Store(&now)
+				pickedTemplate.Store(&rndTemplate)
+
+				return rndTemplate
+			}
+		}
+	}
+
+	return cfg.TemplateName // the fallback of the fallback :D
+}
+
+// write the content to the response writer and log the error if any.
 func write[T string | []byte](w http.ResponseWriter, log *logger.Logger, content T) {
 	var data []byte