Add support for configurable monitoring (traefik#11)

Author: packruler

.devcontainer/Dockerfile

@@ -17,5 +17,8 @@ RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
 USER vscode
 RUN go install mvdan.cc/gofumpt@latest
 
+ENV YAEGI_VERSION="v0.9.20"
+RUN curl -sfL https://raw.githubusercontent.com/traefik/yaegi/master/install.sh | bash -s -- -b $(go env GOPATH)/bin ${YAEGI_VERSION}
+
 # [Optional] Uncomment this line to install global node packages.
 # RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1

.devcontainer/devcontainer.json

@@ -44,5 +44,7 @@
 	"remoteUser": "vscode",
 	"features": {
 		"git": "latest"
-	}
+	},
+	"workspaceMount": "source=${localWorkspaceFolder},target=/go/src/github.com/${localWorkspaceFolderBasename},type=bind,consistency=cached",
+	"workspaceFolder": "/go/src/github.com/${localWorkspaceFolderBasename}"
 }

.github/workflows/main.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - master
+      - plugin-utils
     tags:
       - v*
   pull_request:

.golangci.yaml

@@ -67,3 +67,7 @@ issues:
         - goconst
         - funlen
         - godot
+        - lll
+    - path: config.go
+      linters:
+        - lll

.traefik.yml

@@ -11,3 +11,7 @@ testData:
   rewrites:
     - regex: "bar"
       replacement: "foo"
+  monitor:
+    types:
+      - text/html
+    methods: ["GET"]

README.md

@@ -43,7 +43,7 @@ experimental:
     plugins:
         rewrite-body:
             moduleName: "github.com/packruler/rewrite-body"
-            version: "v1.0.1"
+            version: "v1.1.0"
 ```
 
 ### Dynamic
@@ -77,8 +77,21 @@ http:
               replacement: "bar"
 
           # logLevel is optional, defaults to Info level.
-          # Available logLevels: (Trace: -1, Debug: 1, Info: 2, Warning: 3, Error: 4)
-          logLevel: 2
+          # Available logLevels: (Trace: -2, Debug: -1, Info: 0, Warning: 1, Error: 2)
+          logLevel: 0
+
+          # monitoring is optional, defaults to below configuration
+          # monitoring configuration limits the HTTP queries that are checked for regex replacement.
+          monitoring:
+            # methods is a string list. Options are standard HTTP Methods. Entries MUST be ALL CAPS
+            # For a list of options: https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
+            methods:
+              - GET
+            # types is a string list. Options are HTTP Content Types. Entries should match standard formatting
+            # For a list of options: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types
+            # Wildcards(*) are not supported!
+            types:
+              - text/html
   services:
     my-service:
       loadBalancer:

compressutil/compressions.go

@@ -0,0 +1,10 @@
+package compressutil
+
+const (
+	// Gzip compression algorithm string.
+	Gzip string = "gzip"
+	// Deflate compression algorithm string.
+	Deflate string = "deflate"
+	// Identity compression algorithm string.
+	Identity string = "identity"
+)

compressutil/compressutil.go

@@ -17,21 +17,24 @@ type ReaderError struct {
 }
 
 // Decode data in a bytes.Reader based on supplied encoding.
-func Decode(byteReader *bytes.Buffer, encoding string) (data []byte, err error) {
+func Decode(byteReader *bytes.Buffer, encoding string) ([]byte, error) {
 	reader, err := getRawReader(byteReader, encoding)
 	if err != nil {
-		return nil, &ReaderError{cause: err}
+		return nil, &ReaderError{
+			error: err,
+			cause: err,
+		}
 	}
 
 	return io.ReadAll(reader)
 }
 
 func getRawReader(byteReader *bytes.Buffer, encoding string) (io.Reader, error) {
 	switch encoding {
-	case "gzip":
+	case Gzip:
 		return gzip.NewReader(byteReader)
 
-	case "deflate":
+	case Deflate:
 		return flate.NewReader(byteReader), nil
 
 	default:
@@ -42,10 +45,10 @@ func getRawReader(byteReader *bytes.Buffer, encoding string) (io.Reader, error)
 // Encode data in a []byte based on supplied encoding.
 func Encode(data []byte, encoding string) ([]byte, error) {
 	switch encoding {
-	case "gzip":
+	case Gzip:
 		return compressWithGzip(data)
 
-	case "deflate":
+	case Deflate:
 		return compressWithZlib(data)
 
 	default:

compressutil/compressutil_test.go

@@ -33,21 +33,21 @@ func TestEncode(t *testing.T) {
 			desc:        "should support identity",
 			input:       normalBytes,
 			expected:    normalBytes,
-			encoding:    "identity",
+			encoding:    compressutil.Identity,
 			shouldMatch: true,
 		},
 		{
 			desc:        "should support gzip",
 			input:       normalBytes,
 			expected:    gzippedBytes,
-			encoding:    "gzip",
+			encoding:    compressutil.Gzip,
 			shouldMatch: false,
 		},
 		{
 			desc:        "should support deflate",
 			input:       normalBytes,
 			expected:    deflatedBytes,
-			encoding:    "deflate",
+			encoding:    compressutil.Deflate,
 			shouldMatch: false,
 		},
 		{
@@ -102,21 +102,21 @@ func TestDecode(t *testing.T) {
 			desc:        "should support identity",
 			input:       normalBytes,
 			expected:    normalBytes,
-			encoding:    "identity",
+			encoding:    compressutil.Identity,
 			shouldMatch: true,
 		},
 		{
 			desc:        "should support gzip",
 			input:       gzippedBytes,
 			expected:    normalBytes,
-			encoding:    "gzip",
+			encoding:    compressutil.Gzip,
 			shouldMatch: false,
 		},
 		{
 			desc:        "should support deflate",
 			input:       deflatedBytes,
 			expected:    normalBytes,
-			encoding:    "deflate",
+			encoding:    compressutil.Deflate,
 			shouldMatch: false,
 		},
 		{

config.go

@@ -0,0 +1,31 @@
+package rewrite_body
+
+import (
+	"regexp"
+
+	"github.com/packruler/rewrite-body/httputil"
+)
+
+// Rewrite holds one rewrite body configuration.
+type Rewrite struct {
+	Regex       string `json:"regex" yaml:"regex" toml:"regex"`
+	Replacement string `json:"replacement" yaml:"replacement" toml:"replacement"`
+}
+
+// Config holds the plugin configuration.
+type Config struct {
+	LastModified bool                      `json:"lastModified" toml:"lastModified" yaml:"lastModified"`
+	Rewrites     []Rewrite                 `json:"rewrites" toml:"rewrites" yaml:"rewrites"`
+	LogLevel     int8                      `json:"logLevel" toml:"logLevel" yaml:"logLevel"`
+	Monitoring   httputil.MonitoringConfig `json:"monitoring" toml:"monitoring" yaml:"monitoring"`
+}
+
+// CreateConfig creates and initializes the plugin configuration.
+func CreateConfig() *Config {
+	return &Config{}
+}
+
+type rewrite struct {
+	regex       *regexp.Regexp
+	replacement []byte
+}