chore: update CI, dependencies, and linter

Co-authored-by: Fernandez Ludovic <ldez@users.noreply.github.com>

.github/workflows/ci.yml

@@ -12,32 +12,23 @@ jobs:
     name: Main Process
     runs-on: ubuntu-latest
     env:
-      GO_VERSION: 1.17
+      GO_VERSION: stable
-      GOLANGCI_LINT_VERSION: v1.44.0
+      GOLANGCI_LINT_VERSION: v1.58.0
       CGO_ENABLED: 0
 
     steps:
 
-      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@v2
-        with:
-          go-version: ${{ env.GO_VERSION }}
-
       # https://github.com/marketplace/actions/checkout
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      # https://github.com/marketplace/actions/cache
+      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Cache Go modules
+      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/cache@v2
+        uses: actions/setup-go@v5
         with:
-          path: ~/go/pkg/mod
+          go-version: ${{ env.GO_VERSION }}
-          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-          restore-keys: |
-            ${{ runner.os }}-go-
 
       - name: Check and get dependencies
         run: |

.github/workflows/go-cross.yml

@@ -1,5 +1,9 @@
 name: Go Matrix
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
 
 jobs:
 
@@ -11,37 +15,19 @@ jobs:
 
     strategy:
       matrix:
-        go-version: [ 1.17, 1.x ]
+        go-version: [ stable, oldstable ]
         os: [ubuntu-latest, macos-latest, windows-latest]
 
     steps:
-      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Set up Go ${{ matrix.go-version }}
-        uses: actions/setup-go@v2
-        with:
-          go-version: ${{ matrix.go-version }}
-
       # https://github.com/marketplace/actions/checkout
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
-      # https://github.com/marketplace/actions/cache
+      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Cache Go modules
+      - name: Set up Go ${{ matrix.go-version }}
-        uses: actions/cache@v2
+        uses: actions/setup-go@v5
         with:
-          # In order:
+          go-version: ${{ matrix.go-version }}
-          # * Module download cache
-          # * Build cache (Linux)
-          # * Build cache (Mac)
-          # * Build cache (Windows)
-          path: |
-            ~/go/pkg/mod
-            ~/.cache/go-build
-            ~/Library/Caches/go-build
-            %LocalAppData%\go-build
-          key: ${{ runner.os }}-${{ matrix.go-version }}-go-${{ hashFiles('**/go.sum') }}
-          restore-keys: |
-            ${{ runner.os }}-${{ matrix.go-version }}-go-
 
       - name: Test
         run: go test -v -cover ./...

.github/workflows/release.yml

@@ -9,36 +9,47 @@ jobs:
     name: Release Process
     runs-on: ubuntu-latest
     env:
-      GO_VERSION: 1.17
+      GO_VERSION: stable
-      SEIHON_VERSION: v0.9.0
       CGO_ENABLED: 0
 
     steps:
 
-      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@v2
-        with:
-          go-version: ${{ env.GO_VERSION }}
-
       # https://github.com/marketplace/actions/checkout
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      # Install Docker image multi-arch builder
+      # https://github.com/marketplace/actions/setup-go-environment
-      - name: Install seihon ${{ env.SEIHON_VERSION }}
+      - name: Set up Go ${{ env.GO_VERSION }}
-        run: |
+        uses: actions/setup-go@v5
-          curl -sSfL https://raw.githubusercontent.com/ldez/seihon/master/godownloader.sh | sh -s -- -b $(go env GOPATH)/bin ${SEIHON_VERSION}
+        with:
-          seihon --version
+          go-version: ${{ env.GO_VERSION }}
 
-      - name: Docker Login
+      - name: dockerhub-login
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: ghcr-login
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: traefiker
+          password: ${{ secrets.GHCR_TOKEN }}
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      # https://goreleaser.com/ci/actions/
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v5
+        with:
+          version: latest
+          args: release --clean
         env:
-          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+          GITHUB_TOKEN: ${{ secrets.GH_TOKEN_REPO }}
-          DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
-        run: |
-          echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin
-
-      - name: Deploy Docker Images (seihon)
-        run: make publish-images

.golangci.yml

@@ -1,47 +1,96 @@
 run:
-  deadline: 2m
+  timeout: 2m
-  skip-files: []
+
 linters-settings:
   govet:
-    check-shadowing: true
+    enable-all: true
+    disable:
+      - fieldalignment
   gocyclo:
-    min-complexity: 12
+    min-complexity: 16
   goconst:
     min-len: 3
     min-occurrences: 3
   misspell:
     locale: US
+  funlen:
+    lines: -1
+    statements: 40
+  gofumpt:
+    extra-rules: true
+  depguard:
+    rules:
+      main:
+        deny:
+          - pkg: "github.com/instana/testify"
+            desc: not allowed
+          - pkg: "github.com/pkg/errors"
+            desc: Should be replaced by standard lib errors package
+  godox:
+    keywords:
+      - FIXME
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - style
+      - performance
+    disabled-checks:
+      - sloppyReassign
+      - rangeValCopy
+      - octalLiteral
+      - paramTypeCombine # already handle by gofumpt.extra-rules
+    settings:
+      hugeParam:
+        sizeThreshold: 100
+  forbidigo:
+    forbid:
+      - '^print(ln)?$'
+      - '^panic$'
+      - '^spew\.Print(f|ln)?$'
+      - '^spew\.Dump$'
 
 linters:
   enable-all: true
   disable:
+    - deadcode # deprecated
+    - exhaustivestruct # deprecated
     - golint # deprecated
-    - scopelint # deprecated
+    - ifshort # deprecated
     - interfacer # deprecated
     - maligned # deprecated
-    - lll
+    - nosnakecase # deprecated
-    - gosec
+    - scopelint # deprecated
+    - scopelint # deprecated
+    - structcheck # deprecated
+    - varcheck # deprecated
+    - execinquery # not relevant (SQL)
+    - rowserrcheck # not relevant (SQL)
+    - sqlclosecheck # not relevant (SQL)
+    - cyclop # duplicate of gocyclo
     - dupl
-    - prealloc
+    - exhaustive
+    - exhaustruct
+    - forbidigo
     - gochecknoglobals
     - gochecknoinits
+    - err113
+    - mnd
     - gomnd
-    - wsl
+    - gosec
-    - nlreturn
+    - lll
-    - testpackage
-    - paralleltest
-    - tparallel
-    - goerr113
-    - wrapcheck
-    - exhaustive
-    - exhaustivestruct
-    - forbidigo
-    - varnamelen
     - nilnil
-    - ifshort
+    - nlreturn
+    - paralleltest
+    - prealloc
+    - testpackage
+    - tparallel
+    - varnamelen
+    - wrapcheck
+    - wsl
 
 issues:
   exclude-use-default: false
-  max-per-linter: 0
+  max-issues-per-linter: 0
   max-same-issues: 0
-  exclude: []
+  exclude:
+    - 'package-comments: should have a package comment'

.goreleaser.yml

@@ -0,0 +1,142 @@
+project_name: whoami
+
+builds:
+  - binary: whoami
+    goos:
+      - windows
+      - darwin
+      - linux
+    goarch:
+      - amd64
+      - arm
+      - arm64
+    goarm:
+      - '7'
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - '^docs:'
+      - '^doc:'
+      - '^chore:'
+      - '^chore(deps):'
+      - '^test:'
+      - '^tests:'
+
+archives:
+  - id: whoami
+    name_template: '{{ .ProjectName }}_v{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm}}v{{ .Arm }}{{ end }}'
+    format: tar.gz
+    format_overrides:
+      - goos: windows
+        format: zip
+    files:
+      - LICENSE
+
+docker_manifests:
+  - name_template: 'traefik/whoami:{{ .Tag }}'
+    image_templates:
+      - 'traefik/whoami:{{ .Tag }}-amd64'
+      - 'traefik/whoami:{{ .Tag }}-arm64'
+      - 'traefik/whoami:{{ .Tag }}-armv7'
+  - name_template: 'traefik/whoami:latest'
+    image_templates:
+      - 'traefik/whoami:{{ .Tag }}-amd64'
+      - 'traefik/whoami:{{ .Tag }}-arm64'
+      - 'traefik/whoami:{{ .Tag }}-armv7'
+  - name_template: 'traefik/whoami:v{{ .Major }}.{{ .Minor }}'
+    image_templates:
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-amd64'
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-arm64'
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-armv7'
+
+  - name_template: 'ghcr.io/traefik/whoami:{{ .Tag }}'
+    image_templates:
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-amd64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-arm64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-armv7'
+  - name_template: 'ghcr.io/traefik/whoami:latest'
+    image_templates:
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-amd64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-arm64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-armv7'
+  - name_template: 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}'
+    image_templates:
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-amd64'
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-arm64'
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-armv7'
+
+dockers:
+  - use: buildx
+    goos: linux
+    goarch: amd64
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'traefik/whoami:latest-amd64'
+      - 'traefik/whoami:{{ .Tag }}-amd64'
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-amd64'
+      - 'ghcr.io/traefik/whoami:latest-amd64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-amd64'
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-amd64'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Tiny Go webserver that prints OS information and HTTP request to output'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation={{.GitURL}}'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/amd64'
+
+  - use: buildx
+    goos: linux
+    goarch: arm64
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'traefik/whoami:latest-arm64'
+      - 'traefik/whoami:{{ .Tag }}-arm64'
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-arm64'
+      - 'ghcr.io/traefik/whoami:latest-arm64'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-arm64'
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-arm64'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Tiny Go webserver that prints OS information and HTTP request to output'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation={{.GitURL}}'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/arm64'
+
+  - use: buildx
+    goos: linux
+    goarch: arm
+    goarm: '7'
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'traefik/whoami:latest-armv7'
+      - 'traefik/whoami:{{ .Tag }}-armv7'
+      - 'traefik/whoami:v{{ .Major }}.{{ .Minor }}-armv7'
+      - 'ghcr.io/traefik/whoami:latest-armv7'
+      - 'ghcr.io/traefik/whoami:{{ .Tag }}-armv7'
+      - 'ghcr.io/traefik/whoami:v{{ .Major }}.{{ .Minor }}-armv7'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Tiny Go webserver that prints OS information and HTTP request to output'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation={{.GitURL}}'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/arm/v7'

Makefile

@@ -1,6 +1,4 @@
-.PHONY: default build image check publish-images
+.PHONY: default check test build image
-
-TAG_NAME := $(shell git tag -l --contains HEAD)
 
 IMAGE_NAME := traefik/whoami
 
@@ -17,6 +15,3 @@ check:
 
 image:
 	docker build -t $(IMAGE_NAME) .
-
-publish-images:
-	seihon publish -v "$(TAG_NAME)" -v "latest" --image-name $(IMAGE_NAME) --dry-run=false

README.md

@@ -16,9 +16,13 @@ Returns the whoami information (request and network information).
 The optional `wait` query parameter can be provided to tell the server to wait before sending the response.
 The duration is expected in Go's [`time.Duration`](https://golang.org/pkg/time/#ParseDuration) format (e.g. `/?wait=100ms` to wait 100 milliseconds).
 
+The optional `env` query parameter can be set to `true` to add the environment variables to the response.
+
 #### `/api`
 
-Returns the whoami information as JSON.
+Returns the whoami information (and some extra information) as JSON.
+
+The optional `env` query parameter can be set to `true` to add the environment variables to the response.
 
 #### `/bench`
 
@@ -104,6 +108,6 @@ services:
     image: traefik/whoami
     command:
        # It tells whoami to start listening on 2001 instead of 80
-       - --port 2001
+       - --port=2001
-       - --name iamfoo
+       - --name=iamfoo
 ```

app.go

@@ -1,18 +1,15 @@
 package main
 
 import (
-	"bytes"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
-	"net/url"
 	"os"
 	"strconv"
 	"strings"
@@ -31,6 +28,14 @@ const (
 	TB
 )
 
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+	CheckOrigin: func(_ *http.Request) bool {
+		return true
+	},
+}
+
 var (
 	cert    string
 	key     string
@@ -49,9 +54,17 @@ func init() {
 	flag.StringVar(&name, "name", os.Getenv("WHOAMI_NAME"), "give me a name")
 }
 
-var upgrader = websocket.Upgrader{
+// Data whoami information.
-	ReadBufferSize:  1024,
+type Data struct {
-	WriteBufferSize: 1024,
+	Hostname   string            `json:"hostname,omitempty"`
+	IP         []string          `json:"ip,omitempty"`
+	Headers    http.Header       `json:"headers,omitempty"`
+	URL        string            `json:"url,omitempty"`
+	Host       string            `json:"host,omitempty"`
+	Method     string            `json:"method,omitempty"`
+	Name       string            `json:"name,omitempty"`
+	RemoteAddr string            `json:"remoteAddr,omitempty"`
+	Environ    map[string]string `json:"environ,omitempty"`
 }
 
 func main() {
@@ -76,7 +89,7 @@ func main() {
 		Handler: mux,
 	}
 
-	if len(ca) > 0 {
+	if ca != "" {
 		server.TLSConfig = setupMutualTLS(ca)
 	}
 
@@ -86,7 +99,7 @@ func main() {
 }
 
 func setupMutualTLS(ca string) *tls.Config {
-	clientCACert, err := ioutil.ReadFile(ca)
+	clientCACert, err := os.ReadFile(ca)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -153,8 +166,7 @@ func printBinary(s []byte) {
 }
 
 func dataHandler(w http.ResponseWriter, r *http.Request) {
-	u, _ := url.Parse(r.URL.String())
+	queryParams := r.URL.Query()
-	queryParams := u.Query()
 
 	size, err := strconv.ParseInt(queryParams.Get("size"), 10, 64)
 	if err != nil {
@@ -181,7 +193,7 @@ func dataHandler(w http.ResponseWriter, r *http.Request) {
 		attachment = false
 	}
 
-	content := fillContent(size)
+	content := &contentReader{size: size}
 
 	if attachment {
 		w.Header().Set("Content-Disposition", "Attachment")
@@ -195,10 +207,11 @@ func dataHandler(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func whoamiHandler(w http.ResponseWriter, req *http.Request) {
+func whoamiHandler(w http.ResponseWriter, r *http.Request) {
-	u, _ := url.Parse(req.URL.String())
+	queryParams := r.URL.Query()
-	wait := u.Query().Get("wait")
+
-	if len(wait) > 0 {
+	wait := queryParams.Get("wait")
+	if wait != "" {
 		duration, err := time.ParseDuration(wait)
 		if err == nil {
 			time.Sleep(duration)
@@ -212,66 +225,47 @@ func whoamiHandler(w http.ResponseWriter, req *http.Request) {
 	hostname, _ := os.Hostname()
 	_, _ = fmt.Fprintln(w, "Hostname:", hostname)
 
-	ifaces, _ := net.Interfaces()
+	for _, ip := range getIPs() {
-	for _, i := range ifaces {
+		_, _ = fmt.Fprintln(w, "IP:", ip)
-		addrs, _ := i.Addrs()
-		// handle err
-		for _, addr := range addrs {
-			var ip net.IP
-			switch v := addr.(type) {
-			case *net.IPNet:
-				ip = v.IP
-			case *net.IPAddr:
-				ip = v.IP
-			}
-			_, _ = fmt.Fprintln(w, "IP:", ip)
-		}
 	}
 
-	_, _ = fmt.Fprintln(w, "RemoteAddr:", req.RemoteAddr)
+	_, _ = fmt.Fprintln(w, "RemoteAddr:", r.RemoteAddr)
-	if err := req.Write(w); err != nil {
+	if err := r.Write(w); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+
+	if ok, _ := strconv.ParseBool(queryParams.Get("env")); ok {
+		for _, env := range os.Environ() {
+			_, _ = fmt.Fprintln(w, env)
+		}
+	}
 }
 
-func apiHandler(w http.ResponseWriter, req *http.Request) {
+func apiHandler(w http.ResponseWriter, r *http.Request) {
+	queryParams := r.URL.Query()
+
 	hostname, _ := os.Hostname()
 
-	data := struct {
+	environ := make(map[string]string)
-		Hostname string      `json:"hostname,omitempty"`
+
-		IP       []string    `json:"ip,omitempty"`
+	if ok, _ := strconv.ParseBool(queryParams.Get("env")); ok {
-		Headers  http.Header `json:"headers,omitempty"`
+		for _, env := range os.Environ() {
-		URL      string      `json:"url,omitempty"`
+			before, after, _ := strings.Cut(env, "=")
-		Host     string      `json:"host,omitempty"`
+			environ[before] = after
-		Method   string      `json:"method,omitempty"`
+		}
-		Name     string      `json:"name,omitempty"`
-	}{
-		Hostname: hostname,
-		IP:       []string{},
-		Headers:  req.Header,
-		URL:      req.URL.RequestURI(),
-		Host:     req.Host,
-		Method:   req.Method,
-		Name:     name,
 	}
 
-	ifaces, _ := net.Interfaces()
+	data := Data{
-	for _, i := range ifaces {
+		Hostname:   hostname,
-		addrs, _ := i.Addrs()
+		IP:         getIPs(),
-		// handle err
+		Headers:    r.Header,
-		for _, addr := range addrs {
+		URL:        r.URL.RequestURI(),
-			var ip net.IP
+		Host:       r.Host,
-			switch v := addr.(type) {
+		Method:     r.Method,
-			case *net.IPNet:
+		Name:       name,
-				ip = v.IP
+		RemoteAddr: r.RemoteAddr,
-			case *net.IPAddr:
+		Environ:    environ,
-				ip = v.IP
-			}
-			if ip != nil {
-				data.IP = append(data.IP, ip.String())
-			}
-		}
 	}
 
 	w.Header().Set("Content-Type", "application/json")
@@ -311,26 +305,34 @@ func healthHandler(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
-func fillContent(length int64) io.ReadSeeker {
-	charset := "-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-	b := make([]byte, length)
-
-	for i := range b {
-		b[i] = charset[i%len(charset)]
-	}
-
-	if length > 0 {
-		b[0] = '|'
-		b[length-1] = '|'
-	}
-
-	return bytes.NewReader(b)
-}
-
 func getEnv(key, fallback string) string {
 	value := os.Getenv(key)
-	if len(value) == 0 {
+	if value == "" {
 		return fallback
 	}
 	return value
 }
+
+func getIPs() []string {
+	var ips []string
+
+	ifaces, _ := net.Interfaces()
+	for _, i := range ifaces {
+		addrs, _ := i.Addrs()
+		// handle err
+		for _, addr := range addrs {
+			var ip net.IP
+			switch v := addr.(type) {
+			case *net.IPNet:
+				ip = v.IP
+			case *net.IPAddr:
+				ip = v.IP
+			}
+			if ip != nil {
+				ips = append(ips, ip.String())
+			}
+		}
+	}
+
+	return ips
+}

buildx.Dockerfile

@@ -1,25 +1,17 @@
+# syntax=docker/dockerfile:1.2
 FROM golang:1-alpine as builder
 
 RUN apk --no-cache --no-progress add git ca-certificates tzdata make \
     && update-ca-certificates \
     && rm -rf /var/cache/apk/*
 
-WORKDIR /go/whoami
+# syntax=docker/dockerfile:1.2
-
+# Create a minimal container to run a Golang static binary
-# Download go modules
-COPY go.mod .
-COPY go.sum .
-RUN GO111MODULE=on GOPROXY=https://proxy.golang.org go mod download
-
-COPY . .
-
-RUN GOARCH={{ .GoARCH }} GOARM={{ .GoARM }} make build
-
 FROM scratch
 
 COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
-COPY --from=builder /go/whoami/whoami .
+COPY whoami /
 
 ENTRYPOINT ["/whoami"]
 EXPOSE 80

content.go

@@ -0,0 +1,66 @@
+package main
+
+import (
+	"errors"
+	"io"
+)
+
+const contentCharset = "-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+type contentReader struct {
+	size int64
+	cur  int64
+}
+
+// Read implements the io.Read interface.
+func (r *contentReader) Read(p []byte) (int, error) {
+	length := r.size - 1
+
+	if r.cur >= length {
+		return 0, io.EOF
+	}
+	if len(p) == 0 {
+		return 0, nil
+	}
+
+	var n int
+	if r.cur == 0 {
+		p[n] = '|'
+		r.cur++
+		n++
+	}
+
+	for n < len(p) && r.cur <= length {
+		p[n] = contentCharset[int(r.cur)%len(contentCharset)]
+		r.cur++
+		n++
+	}
+
+	if r.cur >= length {
+		p[n-1] = '|'
+	}
+
+	return n, nil
+}
+
+// Seek implements the io.Seek interface.
+func (r *contentReader) Seek(offset int64, whence int) (int64, error) {
+	switch whence {
+	default:
+		return 0, errors.New("seek: invalid whence")
+	case io.SeekStart:
+		offset += 0
+	case io.SeekCurrent:
+		offset += r.cur
+	case io.SeekEnd:
+		offset += r.size - 1
+	}
+
+	if offset < 0 {
+		return 0, errors.New("seek: invalid offset")
+	}
+
+	r.cur = offset
+
+	return offset, nil
+}

content_test.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"io"
+	"testing"
+)
+
+func Test_contentReader_Read(t *testing.T) {
+	tests := []struct {
+		name    string
+		size    int64
+		content string
+	}{
+		{
+			name:    "simple",
+			size:    40,
+			content: "|ABCDEFGHIJKLMNOPQRSTUVWXYZ-ABCDEFGHIJK|",
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			d := &contentReader{size: test.size}
+
+			b, err := io.ReadAll(d)
+			if err != nil {
+				t.Errorf("contentReader.Read() error = %v", err)
+				return
+			}
+
+			if string(b) != test.content {
+				t.Errorf("return content does not match expected value: got %s want %s", b, test.content)
+			}
+		})
+	}
+}
+
+func Test_contentReader_ReadSeek(t *testing.T) {
+	tests := []struct {
+		name       string
+		offset     int64
+		seekWhence int
+		size       int64
+		content    string
+	}{
+		{
+			name:       "simple",
+			offset:     10,
+			seekWhence: io.SeekCurrent,
+			size:       40,
+			content:    "JKLMNOPQRSTUVWXYZ-ABCDEFGHIJK|",
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			d := &contentReader{size: test.size}
+
+			_, err := d.Seek(test.offset, test.seekWhence)
+			if err != nil {
+				t.Errorf("contentReader.Seek() error = %v", err)
+				return
+			}
+
+			b, err := io.ReadAll(d)
+			if err != nil {
+				t.Errorf("contentReader.Read() error = %v", err)
+				return
+			}
+
+			if string(b) != test.content {
+				t.Errorf("return content does not match expected value: got %s want %s", b, test.content)
+			}
+		})
+	}
+}

go.mod

@@ -1,5 +1,7 @@
 module github.com/traefik/whoami
 
-go 1.17
+go 1.21
 
-require github.com/gorilla/websocket v1.4.2
+require github.com/gorilla/websocket v1.5.1
+
+require golang.org/x/net v0.25.0 // indirect

go.sum

@@ -1,2 +1,4 @@
-github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/QY=
-github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
+golang.org/x/net v0.25.0 h1:d/OCCoBEUq33pjydKrGQhw7IlUPI2Oylr+8qLx49kac=
+golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=