feat: implements circuitbreaker layer

doc/README.md

@@ -9,7 +9,7 @@
 ## Référence
 
 - [(FR) - Layers](./fr/references/layers/README.md)
-- [Fichier de configuration](../misc/packaging/common/config.yml)
+- [(FR) - Fichier de configuration](../misc/packaging/common/config.yml)
 
 ## Tutoriels
 

doc/fr/references/layers/README.md

@@ -2,4 +2,5 @@
 
 Vous trouverez ci-dessous la liste des entités "Layer" activables sur vos entité "Proxy":
 
-- [Queue](./queue.md) - File d'attente dynamique
+- [Queue](./queue.md) - File d'attente dynamique
+- [Circuit Breaker](./circuitbreaker.md) - Coupure d'accès à un site ou une sous section de celui ci

doc/fr/references/layers/circuitbreaker.md

@@ -0,0 +1,37 @@
+# Layer "Circuit Breaker"
+
+## Description
+
+Ce layer permet de bloquer l'accès à un site (ou une section de celui ci) ciblé par un proxy.
+
+## Type
+
+`circuitbreaker`
+
+## Options
+
+### `authorizedCIDRs`
+
+- **Type:** `[]string`
+- **Valeur par défaut:** `[]`
+- **Description:** Autoriser les adresses distantes contenues dans un des masques réseau (en notation ["CIDR"](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation) définis à contourner la restriction d'accès.
+
+### `matchURLs`
+
+- **Type:** `[]string`
+- **Valeur par défaut:** `["*"]`
+- **Description:** Limiter l'action du layer à cette liste de patrons d'URLs. 
+
+    Par exemple, si vous souhaitez limiter votre restriction d'accès à l'ensemble d'une section "`/blog`" d'un site, vous pouvez déclarer la valeur `["*/blog*"]`. Les autres URLs du site ne seront pas affectées par la restriction.
+
+### `templateBlock`
+
+- **Type:** `string`
+- **Valeur par défaut:** `"default"`
+- **Description:** Bloc du template HTML pour effectuer le rendu de la page indiquant la restriction d'accès.
+
+    Voir le [fichier de configuration de référence](../../../../misc/packaging/common/config.yml), section `layers.circuitbreaker` pour voir les options permettant de personnaliser le chemin du répertoire contenant les templates.
+
+### Schéma
+
+Voir le [schéma JSON](../../../../internal/proxy/director/layer/circuitbreaker/layer-options.json).

internal/config/layers.go

@@ -3,7 +3,8 @@ package config
 import "time"
 
 type LayersConfig struct {
-	Queue QueueLayerConfig `yaml:"queue"`
+	Queue          QueueLayerConfig          `yaml:"queue"`
+	CircuitBreaker CircuitBreakerLayerConfig `yaml:"circuitbreaker"`
 }
 
 func NewDefaultLayersConfig() LayersConfig {
@@ -12,6 +13,9 @@ func NewDefaultLayersConfig() LayersConfig {
 			TemplateDir:      "./layers/queue/templates",
 			DefaultKeepAlive: NewInterpolatedDuration(time.Minute),
 		},
+		CircuitBreaker: CircuitBreakerLayerConfig{
+			TemplateDir: "./layers/circuitbreaker/templates",
+		},
 	}
 }
 
@@ -19,3 +23,7 @@ type QueueLayerConfig struct {
 	TemplateDir      InterpolatedString    `yaml:"templateDir"`
 	DefaultKeepAlive *InterpolatedDuration `yaml:"defaultKeepAlive"`
 }
+
+type CircuitBreakerLayerConfig struct {
+	TemplateDir InterpolatedString `yaml:"templateDir"`
+}

internal/proxy/director/layer/circuitbreaker/layer-options.json

@@ -0,0 +1,23 @@
+{
+    "$id": "https://forge.cadoles.com/cadoles/bouncer/schemas/circuitbreaker-layer-options",
+    "title": "Circuit breaker layer options",
+    "type": "object",
+    "properties": {
+        "matchURLs": {
+            "type": "array",
+            "items": {
+                "type": "string"
+            }
+        },
+        "authorizedCIDRs": {
+            "type": "array",
+            "items": {
+                "type": "string"
+            }
+        },
+        "templateBlock": {
+            "type": "string"
+        }
+    },
+    "additionalProperties": false
+}

internal/proxy/director/layer/circuitbreaker/layer.go

@@ -0,0 +1,151 @@
+package circuitbreaker
+
+import (
+	"context"
+	"html/template"
+	"net"
+	"net/http"
+	"path/filepath"
+	"sync"
+
+	"forge.cadoles.com/Cadoles/go-proxy"
+	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
+	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"github.com/Masterminds/sprig/v3"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/logger"
+)
+
+const LayerType store.LayerType = "circuitbreaker"
+
+type Layer struct {
+	templateDir string
+	loadOnce    sync.Once
+	tmpl        *template.Template
+}
+
+// LayerType implements director.MiddlewareLayer
+func (l *Layer) LayerType() store.LayerType {
+	return LayerType
+}
+
+// Middleware implements director.MiddlewareLayer
+func (l *Layer) Middleware(layer *store.Layer) proxy.Middleware {
+	return func(h http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
+
+			options, err := fromStoreOptions(layer.Options)
+			if err != nil {
+				logger.Error(ctx, "could not parse layer options", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			matches, err := l.matchAnyAuthorizedCIDRs(ctx, r.RemoteAddr, options.AuthorizedCIDRs)
+			if err != nil {
+				logger.Error(ctx, "could not match authorized cidrs", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			if matches {
+				h.ServeHTTP(w, r)
+
+				return
+			}
+
+			matches = wildcard.MatchAny(r.URL.String(), options.MatchURLs...)
+			if !matches {
+				h.ServeHTTP(w, r)
+
+				return
+			}
+
+			l.renderCircuitBreakerPage(w, r, layer, options)
+		}
+
+		return http.HandlerFunc(fn)
+	}
+}
+
+func (l *Layer) matchAnyAuthorizedCIDRs(ctx context.Context, remoteHostPort string, CIDRs []string) (bool, error) {
+	remoteHost, _, err := net.SplitHostPort(remoteHostPort)
+	if err != nil {
+		return false, errors.WithStack(err)
+	}
+
+	remoteAddr := net.ParseIP(remoteHost)
+	if remoteAddr == nil {
+		return false, errors.Errorf("remote host '%s' is not a valid ip address", remoteHost)
+	}
+
+	for _, rawCIDR := range CIDRs {
+		_, net, err := net.ParseCIDR(rawCIDR)
+		if err != nil {
+			return false, errors.WithStack(err)
+		}
+
+		match := net.Contains(remoteAddr)
+		if !match {
+			continue
+		}
+
+		return true, nil
+	}
+
+	logger.Debug(ctx, "comparing remote host with authorized cidrs", logger.F("remoteAddr", remoteAddr))
+
+	return false, nil
+}
+
+func (l *Layer) renderCircuitBreakerPage(w http.ResponseWriter, r *http.Request, layer *store.Layer, options *LayerOptions) {
+	ctx := r.Context()
+
+	pattern := filepath.Join(l.templateDir, "*.gohtml")
+
+	logger.Info(ctx, "loading circuit breaker page templates", logger.F("pattern", pattern))
+
+	tmpl, err := template.New("").Funcs(sprig.FuncMap()).ParseGlob(pattern)
+	if err != nil {
+		logger.Error(ctx, "could not load circuit breaker templates", logger.E(errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+
+	templateData := struct {
+		Layer        *store.Layer
+		LayerOptions *LayerOptions
+	}{
+		Layer:        layer,
+		LayerOptions: options,
+	}
+
+	w.Header().Add("Cache-Control", "no-cache")
+
+	w.WriteHeader(http.StatusOK)
+
+	if err := tmpl.ExecuteTemplate(w, options.TemplateBlock, templateData); err != nil {
+		logger.Error(ctx, "could not render circuit breaker page", logger.E(errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+}
+
+func New(funcs ...OptionFunc) *Layer {
+	opts := defaultOptions()
+	for _, fn := range funcs {
+		fn(opts)
+	}
+
+	return &Layer{
+		templateDir: opts.TemplateDir,
+	}
+}
+
+var _ director.MiddlewareLayer = &Layer{}

internal/proxy/director/layer/circuitbreaker/layer_options.go

@@ -0,0 +1,36 @@
+package circuitbreaker
+
+import (
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"github.com/mitchellh/mapstructure"
+	"github.com/pkg/errors"
+)
+
+type LayerOptions struct {
+	MatchURLs       []string `mapstructure:"matchURLs"`
+	AuthorizedCIDRs []string `mapstructure:"authorizedCIDRs"`
+	TemplateBlock   string   `mapstructure:"templateBlock"`
+}
+
+func fromStoreOptions(storeOptions store.LayerOptions) (*LayerOptions, error) {
+	layerOptions := LayerOptions{
+		MatchURLs:       []string{"*"},
+		AuthorizedCIDRs: []string{},
+		TemplateBlock:   "default",
+	}
+
+	config := mapstructure.DecoderConfig{
+		Result: &layerOptions,
+	}
+
+	decoder, err := mapstructure.NewDecoder(&config)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := decoder.Decode(storeOptions); err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return &layerOptions, nil
+}

internal/proxy/director/layer/circuitbreaker/options.go

@@ -0,0 +1,19 @@
+package circuitbreaker
+
+type Options struct {
+	TemplateDir string
+}
+
+type OptionFunc func(*Options)
+
+func defaultOptions() *Options {
+	return &Options{
+		TemplateDir: "./templates",
+	}
+}
+
+func WithTemplateDir(templateDir string) OptionFunc {
+	return func(o *Options) {
+		o.TemplateDir = templateDir
+	}
+}

internal/proxy/director/layer/circuitbreaker/schema.go

@@ -0,0 +1,8 @@
+package circuitbreaker
+
+import (
+	_ "embed"
+)
+
+//go:embed layer-options.json
+var RawLayerOptionsSchema []byte

internal/setup/circuitbreaker_layer.go

@@ -0,0 +1,21 @@
+package setup
+
+import (
+	"forge.cadoles.com/cadoles/bouncer/internal/config"
+	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
+	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director/layer/circuitbreaker"
+)
+
+func init() {
+	RegisterLayer(circuitbreaker.LayerType, setupCircuitBreakerLayer, circuitbreaker.RawLayerOptionsSchema)
+}
+
+func setupCircuitBreakerLayer(conf *config.Config) (director.Layer, error) {
+	options := []circuitbreaker.OptionFunc{
+		circuitbreaker.WithTemplateDir(string(conf.Layers.CircuitBreaker.TemplateDir)),
+	}
+
+	return circuitbreaker.New(
+		options...,
+	), nil
+}

layers/circuitbreaker/templates/default.gohtml

@@ -0,0 +1,73 @@
+{{ define "default" }}
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width,initial-scale=1">
+        <title>Accès bloqué - {{ .Layer.Name }}</title>
+        <style>
+            html {
+              box-sizing: border-box;
+              font-size: 16px;
+            }
+
+            *, *:before, *:after {
+              box-sizing: inherit;
+            }
+
+            body, h1, h2, h3, h4, h5, h6, p, ol, ul {
+              margin: 0;
+              padding: 0;
+              font-weight: normal;
+            }
+
+            html, body {
+              width: 100%;
+              height: 100%;
+              font-family: Arial, Helvetica, sans-serif;
+              background-color: #f7f7f7;
+            }
+
+            #container {
+              display: flex;
+              align-items: center;
+              justify-content: center;
+              height: 100%;
+              flex-direction: column;
+            }
+
+            #card {
+              padding: 1.5em 1em;
+              border: 1px solid #e0e0e0;
+              background-color: white;
+              border-radius: 5px;
+              box-shadow: 2px 2px #cccccc1c;
+              color: #333333 !important;
+            }
+
+            .title {
+              margin-bottom: 1.2em;
+            }
+
+            p {
+              margin-bottom: 0.5em;
+            }
+
+            .footer {
+              font-size: 0.7em;
+              margin-top: 2em;
+              text-align: right;
+            }
+        </style>
+    </head>
+    <body>
+        <div id="container">
+            <div id="card">
+                <h2 class="title">Page indisponible</h2>
+                <p>La page à laquelle vous souhaitez accéder est actuellement indisponible.</p>
+                <p class="footer">Propulsé par <a href="https://forge.cadoles.com/Cadoles/bouncer">Bouncer</a>.</p>
+            </div>
+        </div>
+    </body>
+</html>
+{{ end }}

misc/packaging/common/config.yml

@@ -161,4 +161,10 @@ layers:
         # Répertoire contenant les templates
         templateDir: "/etc/bouncer/layers/queue/templates"
         # Temps de vie par défaut d'une session
-        defaultKeepAlive: 1m
+        defaultKeepAlive: 1m
+    
+    # Configuration du layer "circuitbreaker"
+    circuitbreaker:
+        # Répertoire contenant les templates
+        templateDir: "/etc/bouncer/layers/circuitbreaker/templates"
+