feat: support reading Docker host from the current Docker context

docker_auth.go

@@ -150,7 +150,7 @@ func configKey(cfg *dockercfg.Config) (string, error) {
 // getDockerAuthConfigs returns a map with the auth configs from the docker config file
 // using the registry as the key
 func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
-	cfg, err := getDockerConfig()
+	cfg, err := core.ReadDockerConfig()
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			return map[string]registry.AuthConfig{}, nil
@@ -246,25 +246,3 @@ func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
 
 	return cfgs, nil
 }
-
-// getDockerConfig returns the docker config file. It will internally check, in this particular order:
-// 1. the DOCKER_AUTH_CONFIG environment variable, unmarshalling it into a dockercfg.Config
-// 2. the DOCKER_CONFIG environment variable, as the path to the config file
-// 3. else it will load the default config file, which is ~/.docker/config.json
-func getDockerConfig() (*dockercfg.Config, error) {
-	if env := os.Getenv("DOCKER_AUTH_CONFIG"); env != "" {
-		var cfg dockercfg.Config
-		if err := json.Unmarshal([]byte(env), &cfg); err != nil {
-			return nil, fmt.Errorf("unmarshal DOCKER_AUTH_CONFIG: %w", err)
-		}
-
-		return &cfg, nil
-	}
-
-	cfg, err := dockercfg.LoadDefaultConfig()
-	if err != nil {
-		return nil, fmt.Errorf("load default config: %w", err)
-	}
-
-	return &cfg, nil
-}

docker_auth_test.go

@@ -16,82 +16,11 @@ import (
 	"github.com/docker/docker/client"
 	"github.com/stretchr/testify/require"
 
-	"github.com/testcontainers/testcontainers-go/internal/core"
 	"github.com/testcontainers/testcontainers-go/wait"
 )
 
 const exampleAuth = "https://example-auth.com"
 
-func Test_getDockerConfig(t *testing.T) {
-	expectedConfig := &dockercfg.Config{
-		AuthConfigs: map[string]dockercfg.AuthConfig{
-			core.IndexDockerIO:            {},
-			"https://example.com":         {},
-			"https://my.private.registry": {},
-		},
-		CredentialsStore: "desktop",
-	}
-	t.Run("HOME/valid", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata")
-
-		cfg, err := getDockerConfig()
-		require.NoError(t, err)
-		require.Equal(t, expectedConfig, cfg)
-	})
-
-	t.Run("HOME/not-found", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-
-		cfg, err := getDockerConfig()
-		require.ErrorIs(t, err, os.ErrNotExist)
-		require.Nil(t, cfg)
-	})
-
-	t.Run("HOME/invalid-config", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "invalid-config")
-
-		cfg, err := getDockerConfig()
-		require.ErrorContains(t, err, "json: cannot unmarshal array")
-		require.Nil(t, cfg)
-	})
-
-	t.Run("DOCKER_AUTH_CONFIG/valid", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-		t.Setenv("DOCKER_AUTH_CONFIG", dockerConfig)
-
-		cfg, err := getDockerConfig()
-		require.NoError(t, err)
-		require.Equal(t, expectedConfig, cfg)
-	})
-
-	t.Run("DOCKER_AUTH_CONFIG/invalid-config", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-		t.Setenv("DOCKER_AUTH_CONFIG", `{"auths": []}`)
-
-		cfg, err := getDockerConfig()
-		require.ErrorContains(t, err, "json: cannot unmarshal array")
-		require.Nil(t, cfg)
-	})
-
-	t.Run("DOCKER_CONFIG/valid", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-		t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", ".docker"))
-
-		cfg, err := getDockerConfig()
-		require.NoError(t, err)
-		require.Equal(t, expectedConfig, cfg)
-	})
-
-	t.Run("DOCKER_CONFIG/invalid-config", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-		t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", "invalid-config", ".docker"))
-
-		cfg, err := getDockerConfig()
-		require.ErrorContains(t, err, "json: cannot unmarshal array")
-		require.Nil(t, cfg)
-	})
-}
-
 func TestDockerImageAuth(t *testing.T) {
 	t.Run("retrieve auth with DOCKER_AUTH_CONFIG env var", func(t *testing.T) {
 		username, password := "gopher", "secret"
@@ -421,15 +350,6 @@ func Test_getDockerAuthConfigs(t *testing.T) {
 
 		requireValidAuthConfig(t)
 	})
-
-	t.Run("DOCKER_CONFIG/invalid-config", func(t *testing.T) {
-		testDockerConfigHome(t, "testdata", "not-found")
-		t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", "invalid-config", ".docker"))
-
-		cfg, err := getDockerConfig()
-		require.ErrorContains(t, err, "json: cannot unmarshal array")
-		require.Nil(t, cfg)
-	})
 }
 
 // requireValidAuthConfig checks that the given authConfigs map contains the expected keys.

docs/features/configuration.md

@@ -75,17 +75,19 @@ See [Docker environment variables](https://docs.docker.com/engine/reference/comm
 
 3. Read the Go context for the **DOCKER_HOST** key. E.g. `ctx.Value("DOCKER_HOST")`. This is used internally for the library to pass the Docker host to the resource reaper.
 
-4. Read the default Docker socket path, without the unix schema. E.g. `/var/run/docker.sock`
+4. Read the host endpoint for the current Docker context in the Docker configuration file. E.g. `~/.docker/config.json`.
 
-5. Read the **docker.host** property in the `~/.testcontainers.properties` file. E.g. `docker.host=tcp://my.docker.host:1234`
+5. Read the default Docker socket path, without the unix schema. E.g. `/var/run/docker.sock`
 
-6. Read the rootless Docker socket path, checking in the following alternative locations:
+6. Read the **docker.host** property in the `~/.testcontainers.properties` file. E.g. `docker.host=tcp://my.docker.host:1234`
+
+7. Read the rootless Docker socket path, checking in the following alternative locations:
     1. `${XDG_RUNTIME_DIR}/.docker/run/docker.sock`.
     2. `${HOME}/.docker/run/docker.sock`.
     3. `${HOME}/.docker/desktop/docker.sock`.
     4. `/run/user/${UID}/docker.sock`, where `${UID}` is the user ID of the current user.
 
-7. The library panics if none of the above are set, meaning that the Docker host was not detected.
+8. The library panics if none of the above are set, meaning that the Docker host was not detected.
 
 ## Docker socket path detection
 

generic.go

@@ -78,7 +78,7 @@ func GenericContainer(ctx context.Context, req GenericContainerRequest) (Contain
 		// TODO: Remove this debugging.
 		if strings.Contains(err.Error(), "toomanyrequests") {
 			// Debugging information for rate limiting.
-			cfg, err := getDockerConfig()
+			cfg, err := core.ReadDockerConfig()
 			if err == nil {
 				fmt.Printf("XXX: too many requests: %+v", cfg)
 			}

internal/core/docker_config.go

@@ -0,0 +1,31 @@
+package core
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/cpuguy83/dockercfg"
+)
+
+// ReadDockerConfig returns the docker config file. It will internally check, in this particular order:
+// 1. the DOCKER_AUTH_CONFIG environment variable, unmarshalling it into a dockercfg.Config
+// 2. the DOCKER_CONFIG environment variable, as the path to the config file
+// 3. else it will load the default config file, which is ~/.docker/config.json
+func ReadDockerConfig() (*dockercfg.Config, error) {
+	if env := os.Getenv("DOCKER_AUTH_CONFIG"); env != "" {
+		var cfg dockercfg.Config
+		if err := json.Unmarshal([]byte(env), &cfg); err != nil {
+			return nil, fmt.Errorf("unmarshal DOCKER_AUTH_CONFIG: %w", err)
+		}
+
+		return &cfg, nil
+	}
+
+	cfg, err := dockercfg.LoadDefaultConfig()
+	if err != nil {
+		return nil, fmt.Errorf("load default config: %w", err)
+	}
+
+	return &cfg, nil
+}

internal/core/docker_config_test.go

@@ -0,0 +1,96 @@
+package core
+
+import (
+	_ "embed"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/cpuguy83/dockercfg"
+	"github.com/stretchr/testify/require"
+)
+
+//go:embed testdata/.docker/config.json
+var dockerConfig string
+
+func TestReadDockerConfig(t *testing.T) {
+	expectedConfig := &dockercfg.Config{
+		AuthConfigs: map[string]dockercfg.AuthConfig{
+			IndexDockerIO:                 {},
+			"https://example.com":         {},
+			"https://my.private.registry": {},
+		},
+		CredentialsStore: "desktop",
+	}
+	t.Run("HOME/valid", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata")
+
+		cfg, err := ReadDockerConfig()
+		require.NoError(t, err)
+		require.Equal(t, expectedConfig, cfg)
+	})
+
+	t.Run("HOME/not-found", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "not-found")
+
+		cfg, err := ReadDockerConfig()
+		require.ErrorIs(t, err, os.ErrNotExist)
+		require.Nil(t, cfg)
+	})
+
+	t.Run("HOME/invalid-config", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "invalid-config")
+
+		cfg, err := ReadDockerConfig()
+		require.ErrorContains(t, err, "json: cannot unmarshal array")
+		require.Nil(t, cfg)
+	})
+
+	t.Run("DOCKER_AUTH_CONFIG/valid", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "not-found")
+		t.Setenv("DOCKER_AUTH_CONFIG", dockerConfig)
+
+		cfg, err := ReadDockerConfig()
+		require.NoError(t, err)
+		require.Equal(t, expectedConfig, cfg)
+	})
+
+	t.Run("DOCKER_AUTH_CONFIG/invalid-config", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "not-found")
+		t.Setenv("DOCKER_AUTH_CONFIG", `{"auths": []}`)
+
+		cfg, err := ReadDockerConfig()
+		require.ErrorContains(t, err, "json: cannot unmarshal array")
+		require.Nil(t, cfg)
+	})
+
+	t.Run("DOCKER_CONFIG/valid", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "not-found")
+		t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", ".docker"))
+
+		cfg, err := ReadDockerConfig()
+		require.NoError(t, err)
+		require.Equal(t, expectedConfig, cfg)
+	})
+
+	t.Run("DOCKER_CONFIG/invalid-config", func(t *testing.T) {
+		testDockerConfigHome(t, "testdata", "not-found")
+		t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", "invalid-config", ".docker"))
+
+		cfg, err := ReadDockerConfig()
+		require.ErrorContains(t, err, "json: cannot unmarshal array")
+		require.Nil(t, cfg)
+	})
+}
+
+// testDockerConfigHome sets the user's home directory to the given path
+// and unsets the DOCKER_CONFIG and DOCKER_AUTH_CONFIG environment variables.
+func testDockerConfigHome(t *testing.T, dirs ...string) {
+	t.Helper()
+
+	dir := filepath.Join(dirs...)
+	t.Setenv("DOCKER_AUTH_CONFIG", "")
+	t.Setenv("DOCKER_CONFIG", "")
+	t.Setenv("HOME", dir)
+	t.Setenv("USERPROFILE", dir) // Windows
+}