Rewrite as standalone Go server with httputil.ReverseProxy (#4)

* Initial files

* Initial commit

* Remove weird readme.md

* Fix release script

* Fix release script

* Try this release

* Do not fail-fast

* Try --

* Fix release

* Add the token

* Give it write perms

* Fix release

* Make sure network attachment match uses names instead of id

* Use it as info

* Use warn

* Fix

* Only publish linux amd64

* Rewrite as standalone Go server with httputil.ReverseProxy

Replace Caddy plugin with a standalone HTTP server that properly
handles Docker's connection hijacking for docker run/exec.

* Use standardized CI workflow

* Fix errcheck lint issues

---------

Co-authored-by: Mads Jon Nielsen <mjn@cego.dk>

Author: firecow

.github/workflows/qa.yml

@@ -0,0 +1,61 @@
+name: CI
+
+on:
+  push:
+    branches: [main, initial]
+  pull_request:
+    branches: [main, initial]
+
+jobs:
+  test:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4.2.2
+
+      - uses: actions/setup-go@v5.2.0
+        with:
+          go-version-file: go.mod
+
+      - name: Run tests
+        run: go test -v -race ./...
+
+  lint:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4.2.2
+
+      - uses: actions/setup-go@v5.2.0
+        with:
+          go-version-file: go.mod
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v6.2.0
+        with:
+          version: v2.8.0
+
+  fmt:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4.2.2
+
+      - uses: actions/setup-go@v5.2.0
+        with:
+          go-version-file: go.mod
+
+      - name: Install golangci-lint
+        run: go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.8.0
+
+      - name: Check formatting
+        run: test -z "$(golangci-lint fmt --diff)" || (echo "Run 'golangci-lint fmt' to fix formatting" && exit 1)
+
+  build:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4.2.2
+
+      - uses: actions/setup-go@v5.2.0
+        with:
+          go-version-file: go.mod
+
+      - name: Build
+        run: go build -o docker-api-auth .

.github/workflows/release.yml

@@ -0,0 +1,28 @@
+name: Release binaries
+
+permissions:
+  contents: write
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  releases-amd64:
+    name: Release Go Binary AMD64
+    runs-on: ubuntu-latest
+    steps:
+      - name: Git checkout
+        uses: actions/checkout@v5
+
+      - uses: actions/setup-go@v6
+        with:
+          go-version: stable
+
+      - name: Build
+        run: CGO_ENABLED=0 go build -o docker-api-auth-linux-amd64 .
+
+      - name: Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: docker-api-auth-linux-amd64

.gitignore

@@ -0,0 +1,2 @@
+.*
+docker-api-auth

example/acl.yml

@@ -0,0 +1,7 @@
+---
+deployers:
+
+  - username: example
+    password_hash: $2a$12$RvXRFK7mv.Q4M0ltpwLgL.tqBU2KkFV5i58q7AaDhbPOu9.DU.4qK
+    service_prefix: example_
+    network_attachments: [example-shared]

go.mod

@@ -0,0 +1,38 @@
+module github.com/cego/caddy-docker-api-auth
+
+go 1.25.0
+
+require (
+	github.com/moby/moby/client v0.1.0-beta.0
+	github.com/samber/lo v1.51.0
+	github.com/stretchr/testify v1.10.0
+	go.uber.org/zap v1.27.0
+	golang.org/x/crypto v0.42.0
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/containerd/errdefs v1.0.0 // indirect
+	github.com/containerd/errdefs/pkg v0.3.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/distribution/reference v0.6.0 // indirect
+	github.com/docker/go-connections v0.6.0 // indirect
+	github.com/docker/go-units v0.5.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/moby/docker-image-spec v1.3.1 // indirect
+	github.com/moby/moby/api v1.52.0-beta.1 // indirect
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.60.0 // indirect
+	go.opentelemetry.io/otel v1.35.0 // indirect
+	go.opentelemetry.io/otel/metric v1.35.0 // indirect
+	go.opentelemetry.io/otel/trace v1.35.0 // indirect
+	go.uber.org/multierr v1.10.0 // indirect
+	golang.org/x/sys v0.36.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
+)

go.sum

@@ -0,0 +1,82 @@
+github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
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internal/acl.go

@@ -0,0 +1,74 @@
+package internal
+
+import (
+	"os"
+	"regexp"
+
+	"github.com/samber/lo"
+	"golang.org/x/crypto/bcrypt"
+	"gopkg.in/yaml.v3"
+)
+
+type ACLDeployer struct {
+	servicePrefixRegexp *regexp.Regexp
+
+	Username           string   `yaml:"username"`
+	PasswordHash       string   `yaml:"password_hash"`
+	ServicePrefix      string   `yaml:"service_prefix"`
+	NetworkAttachments []string `yaml:"network_attachments"`
+}
+
+type ACL struct {
+	Deployers []*ACLDeployer `json:"deployers"`
+}
+
+func NewACL(aclFilePath string) *ACL {
+	acl := &ACL{}
+
+	out := MustReturn(os.ReadFile(aclFilePath))
+	MustNotFail(yaml.Unmarshal(out, &acl))
+
+	// Compile and assign regexp's
+	for _, deployer := range acl.Deployers {
+		deployer.servicePrefixRegexp = MustReturn(regexp.Compile("^" + deployer.ServicePrefix))
+	}
+
+	return acl
+}
+
+func (a *ACL) VerifyUser(username string, password string) bool {
+	matches := lo.Filter(a.Deployers, func(item *ACLDeployer, _ int) bool {
+		if item.Username != username {
+			return false
+		}
+
+		err := bcrypt.CompareHashAndPassword([]byte(item.PasswordHash), []byte(password))
+		return err == nil
+	})
+	return len(matches) > 0
+}
+
+func (a *ACL) MatchNetworkAttachment(username string, networkName string) bool {
+	matches := lo.Filter(a.Deployers, func(item *ACLDeployer, _ int) bool {
+		if item.Username != username {
+			return false
+		}
+
+		networkMatches := lo.Filter(item.NetworkAttachments, func(item string, _ int) bool {
+			return item == networkName
+		})
+		return len(networkMatches) > 0
+	})
+	return len(matches) > 0
+}
+
+func (a *ACL) MatchServicePrefix(username string, serviceName string) bool {
+	matches := lo.Filter(a.Deployers, func(item *ACLDeployer, _ int) bool {
+		if item.Username != username {
+			return false
+		}
+
+		return item.servicePrefixRegexp.MatchString(serviceName)
+	})
+	return len(matches) > 0
+}

internal/acl_test.go

@@ -0,0 +1,44 @@
+package internal_test
+
+import (
+	"testing"
+
+	"github.com/cego/caddy-docker-api-auth/internal"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestACL(t *testing.T) {
+	acl := internal.NewACL("../example/acl.yml")
+
+	validExampleUsername := "example"
+	validExamplePassword := "see im a proper password"
+	validExamplePrefix := "example_"
+
+	t.Run("it passes VerifyUser", func(t *testing.T) {
+		found := acl.VerifyUser(validExampleUsername, validExamplePassword)
+		assert.True(t, found)
+	})
+
+	t.Run("it fails VerifyUser with invalid password", func(t *testing.T) {
+		found := acl.VerifyUser(validExampleUsername, "im not a proper password")
+		assert.False(t, found)
+	})
+
+	t.Run("it fails VerifyUser with invalid username", func(t *testing.T) {
+		found := acl.VerifyUser("notavalidusername", validExamplePassword)
+		assert.False(t, found)
+	})
+
+	t.Run("it matches by username and service name", func(t *testing.T) {
+		found := acl.MatchServicePrefix(validExampleUsername, validExamplePrefix)
+		assert.True(t, found)
+	})
+	t.Run("it matches by username, but not service name", func(t *testing.T) {
+		found := acl.MatchServicePrefix(validExampleUsername, "notexample_")
+		assert.False(t, found)
+	})
+	t.Run("it matches by service name, but not username", func(t *testing.T) {
+		found := acl.MatchServicePrefix("invalid-username", validExamplePrefix)
+		assert.False(t, found)
+	})
+}