fix: fix broken write to docker config.json

go.mod

@@ -5,6 +5,7 @@ go 1.23.3
 require (
 	github.com/cenkalti/backoff/v4 v4.3.0
 	github.com/rs/zerolog v1.33.0
+	github.com/stretchr/testify v1.9.0
 	github.com/thegeeklab/wp-plugin-go/v3 v3.0.9
 	github.com/urfave/cli/v2 v2.27.5
 )
@@ -15,6 +16,7 @@ require (
 	github.com/Masterminds/semver/v3 v3.3.0 // indirect
 	github.com/Masterminds/sprig/v3 v3.3.0 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/huandu/xstrings v1.5.0 // indirect
 	github.com/joho/godotenv v1.5.1 // indirect
@@ -22,6 +24,7 @@ require (
 	github.com/mattn/go-isatty v0.0.19 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/shopspring/decimal v1.4.0 // indirect
 	github.com/spf13/cast v1.7.0 // indirect
@@ -29,4 +32,5 @@ require (
 	golang.org/x/crypto v0.29.0 // indirect
 	golang.org/x/net v0.31.0 // indirect
 	golang.org/x/sys v0.27.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -68,6 +68,7 @@ golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
 golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

plugin/impl.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"path/filepath"
 	"time"
 
 	"github.com/cenkalti/backoff/v4"
@@ -129,7 +130,12 @@ func (p *Plugin) Execute() error {
 	}
 
 	if p.Settings.Registry.Config != "" {
-		if err := WriteDockerConf(homeDir, p.Settings.Registry.Config); err != nil {
+		path := filepath.Join(homeDir, ".docker", "config.json")
+		if err := os.MkdirAll(filepath.Dir(path), strictFilePerm); err != nil {
+			return err
+		}
+
+		if err := WriteDockerConf(path, p.Settings.Registry.Config); err != nil {
 			return fmt.Errorf("error writing docker config: %w", err)
 		}
 	}

plugin/plugin.go

@@ -333,9 +333,9 @@ func Flags(settings *Settings, category string) []cli.Flag {
 			Category:    category,
 		},
 		&cli.StringFlag{
-			Name:        "docker.config",
-			EnvVars:     []string{"PLUGIN_CONFIG", "DOCKER_PLUGIN_CONFIG"},
-			Usage:       "content of the docker daemon json config",
+			Name:        "registry.config",
+			EnvVars:     []string{"PLUGIN_REGISTRY_CONFIG", "DOCKER_REGISTRY_CONFIG"},
+			Usage:       "content of the registry credentials store file",
 			Destination: &settings.Registry.Config,
 			DefaultText: "$DOCKER_PLUGIN_CONFIG",
 			Category:    category,

plugin/util.go

@@ -1,11 +1,14 @@
 package plugin
 
 import (
+	"encoding/json"
+	"fmt"
 	"net"
 	"os"
-	"path/filepath"
 )
 
+var errInvalidDockerConfig = fmt.Errorf("invalid docker config")
+
 func GetContainerIP() (string, error) {
 	netInterfaceAddrList, err := net.InterfaceAddrs()
 	if err != nil {
@@ -23,13 +26,17 @@ func GetContainerIP() (string, error) {
 }
 
 func WriteDockerConf(path, conf string) error {
-	confPath := filepath.Join(path, ".docker", "config.json")
-
-	if err := os.MkdirAll(confPath, strictFilePerm); err != nil {
-		return err
+	var jsonData interface{}
+	if err := json.Unmarshal([]byte(conf), &jsonData); err != nil {
+		return fmt.Errorf("%w: %w", errInvalidDockerConfig, err)
 	}
 
-	err := os.WriteFile(path, []byte(conf), strictFilePerm)
+	jsonBytes, err := json.Marshal(jsonData)
+	if err != nil {
+		return fmt.Errorf("%w: %w", errInvalidDockerConfig, err)
+	}
+
+	err = os.WriteFile(path, jsonBytes, strictFilePerm)
 	if err != nil {
 		return err
 	}

plugin/util_test.go

@@ -0,0 +1,56 @@
+package plugin
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWriteDockerConf(t *testing.T) {
+	tests := []struct {
+		name    string
+		conf    string
+		wantErr bool
+	}{
+		{
+			name:    "valid json config",
+			conf:    `{"auths":{"registry.example.com":{"auth":"dXNlcjpwYXNz"}}}`,
+			wantErr: false,
+		},
+		{
+			name:    "invalid json config",
+			conf:    `{"auths":invalid}`,
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpFile := filepath.Join(t.TempDir(), "config.json")
+
+			err := WriteDockerConf(tmpFile, tt.conf)
+			if tt.wantErr {
+				assert.ErrorAs(t, err, &errInvalidDockerConfig)
+
+				return
+			}
+
+			assert.NoError(t, err)
+
+			content, err := os.ReadFile(tmpFile)
+			assert.NoError(t, err, "Failed to read config file")
+
+			var got, want interface{}
+			err = json.Unmarshal(content, &got)
+			assert.NoError(t, err, "Failed to parse written config")
+
+			err = json.Unmarshal([]byte(tt.conf), &want)
+			assert.NoError(t, err, "Failed to parse test config")
+
+			assert.Equal(t, want, got, "Written config does not match expected")
+		})
+	}
+}