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fix: docker config error handling when config file does not exist (#2772
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)

Handle file not exist error in getDockerAuthConfigs, treating it as if
no authentication was provided.

Use config directly for cache instead of loading the file a second time
which may be the wrong file if loaded from the environment.

Correctly handle json decode errors in getDockerConfig instead of
falling back to the default config, which would result in unexpected
behaviour.

Tests refactored to ensure all edge cases for getDockerConfig and
getDockerAuthConfigs are handled.

Fixes #2767
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@stevenh
stevenh authored Sep 9, 2024
1 parent 553afd3 commit 6a947dc
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Showing 3 changed files with 159 additions and 111 deletions.
49 changes: 20 additions & 29 deletions docker_auth.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,6 @@ import (
"encoding/json"
"errors"
"fmt"
"io"
"net/url"
"os"
"sync"
Expand Down Expand Up @@ -137,24 +136,12 @@ func (c *credentialsCache) Get(hostname, configKey string) (string, string, erro
return user, password, nil
}

// configFileKey returns a key to use for caching credentials based on
// configKey returns a key to use for caching credentials based on
// the contents of the currently active config.
func configFileKey() (string, error) {
configPath, err := dockercfg.ConfigPath()
if err != nil {
return "", err
}

f, err := os.Open(configPath)
if err != nil {
return "", fmt.Errorf("open config file: %w", err)
}

defer f.Close()

func configKey(cfg *dockercfg.Config) (string, error) {
h := md5.New()
if _, err := io.Copy(h, f); err != nil {
return "", fmt.Errorf("copying config file: %w", err)
if err := json.NewEncoder(h).Encode(cfg); err != nil {
return "", fmt.Errorf("encode config: %w", err)
}

return hex.EncodeToString(h.Sum(nil)), nil
Expand All @@ -165,10 +152,14 @@ func configFileKey() (string, error) {
func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
cfg, err := getDockerConfig()
if err != nil {
if errors.Is(err, os.ErrNotExist) {
return map[string]registry.AuthConfig{}, nil
}

return nil, err
}

configKey, err := configFileKey()
key, err := configKey(cfg)
if err != nil {
return nil, err
}
Expand All @@ -195,7 +186,7 @@ func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
switch {
case ac.Username == "" && ac.Password == "":
// Look up credentials from the credential store.
u, p, err := creds.Get(k, configKey)
u, p, err := creds.Get(k, key)
if err != nil {
results <- authConfigResult{err: err}
return
Expand All @@ -218,7 +209,7 @@ func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
go func(k string) {
defer wg.Done()

u, p, err := creds.Get(k, configKey)
u, p, err := creds.Get(k, key)
if err != nil {
results <- authConfigResult{err: err}
return
Expand Down Expand Up @@ -260,20 +251,20 @@ func getDockerAuthConfigs() (map[string]registry.AuthConfig, error) {
// 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) {
dockerAuthConfig := os.Getenv("DOCKER_AUTH_CONFIG")
if dockerAuthConfig != "" {
cfg := dockercfg.Config{}
err := json.Unmarshal([]byte(dockerAuthConfig), &cfg)
if err == nil {
return cfg, nil
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 cfg, err
return nil, fmt.Errorf("load default config: %w", err)
}

return cfg, nil
return &cfg, nil
}
218 changes: 136 additions & 82 deletions docker_auth_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,6 @@ import (
"github.com/docker/docker/api/types/image"
"github.com/docker/docker/api/types/registry"
"github.com/docker/docker/client"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"

"github.com/testcontainers/testcontainers-go/internal/core"
Expand All @@ -23,91 +22,87 @@ import (

const exampleAuth = "https://example-auth.com"

var testDockerConfigDirPath = filepath.Join("testdata", ".docker")

var indexDockerIO = core.IndexDockerIO

func TestGetDockerConfig(t *testing.T) {
const expectedErrorMessage = "Expected to find %s in auth configs"

// Verify that the default docker config file exists before any test in this suite runs.
// Then, we can safely run the tests that rely on it.
defaultCfg, err := dockercfg.LoadDefaultConfig()
require.NoError(t, err)
require.NotEmpty(t, defaultCfg)

t.Run("without DOCKER_CONFIG env var retrieves default", func(t *testing.T) {
t.Setenv("DOCKER_CONFIG", "")
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.NotEmpty(t, cfg)
require.Equal(t, expectedConfig, cfg)
})

assert.Equal(t, defaultCfg, 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("with DOCKER_CONFIG env var pointing to a non-existing file raises error", func(t *testing.T) {
t.Setenv("DOCKER_CONFIG", filepath.Join(testDockerConfigDirPath, "non-existing"))
t.Run("HOME/invalid-config", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "invalid-config")

cfg, err := getDockerConfig()
require.Error(t, err)
require.Empty(t, cfg)
require.ErrorContains(t, err, "json: cannot unmarshal array")
require.Nil(t, cfg)
})

t.Run("with DOCKER_CONFIG env var", func(t *testing.T) {
t.Setenv("DOCKER_CONFIG", testDockerConfigDirPath)
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.NotEmpty(t, cfg)

assert.Len(t, cfg.AuthConfigs, 3)
require.Equal(t, expectedConfig, cfg)
})

authCfgs := cfg.AuthConfigs
t.Run("DOCKER_AUTH_CONFIG/invalid-config", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "not-found")
t.Setenv("DOCKER_AUTH_CONFIG", `{"auths": []}`)

if _, ok := authCfgs[indexDockerIO]; !ok {
t.Errorf(expectedErrorMessage, indexDockerIO)
}
if _, ok := authCfgs["https://example.com"]; !ok {
t.Errorf(expectedErrorMessage, "https://example.com")
}
if _, ok := authCfgs["https://my.private.registry"]; !ok {
t.Errorf(expectedErrorMessage, "https://my.private.registry")
}
cfg, err := getDockerConfig()
require.ErrorContains(t, err, "json: cannot unmarshal array")
require.Nil(t, cfg)
})

t.Run("DOCKER_AUTH_CONFIG env var takes precedence", func(t *testing.T) {
setAuthConfig(t, exampleAuth, "", "")
t.Setenv("DOCKER_CONFIG", testDockerConfigDirPath)
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.NotEmpty(t, cfg)

assert.Len(t, cfg.AuthConfigs, 1)
require.Equal(t, expectedConfig, cfg)
})

authCfgs := cfg.AuthConfigs
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"))

if _, ok := authCfgs[indexDockerIO]; ok {
t.Errorf("Not expected to find %s in auth configs", indexDockerIO)
}
if _, ok := authCfgs[exampleAuth]; !ok {
t.Errorf(expectedErrorMessage, exampleAuth)
}
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"
creds := setAuthConfig(t, exampleAuth, username, password)

registry, cfg, err := DockerImageAuth(context.Background(), exampleAuth+"/my/image:latest")
require.NoError(t, err)
require.NotEmpty(t, cfg)

assert.Equal(t, exampleAuth, registry)
assert.Equal(t, username, cfg.Username)
assert.Equal(t, password, cfg.Password)
assert.Equal(t, creds, cfg.Auth)
require.Equal(t, exampleAuth, registry)
require.Equal(t, username, cfg.Username)
require.Equal(t, password, cfg.Password)
require.Equal(t, creds, cfg.Auth)
})

t.Run("match registry authentication by host", func(t *testing.T) {
Expand All @@ -117,12 +112,10 @@ func TestGetDockerConfig(t *testing.T) {

registry, cfg, err := DockerImageAuth(context.Background(), imageReg+imagePath)
require.NoError(t, err)
require.NotEmpty(t, cfg)

assert.Equal(t, imageReg, registry)
assert.Equal(t, "gopher", cfg.Username)
assert.Equal(t, "secret", cfg.Password)
assert.Equal(t, base64, cfg.Auth)
require.Equal(t, imageReg, registry)
require.Equal(t, "gopher", cfg.Username)
require.Equal(t, "secret", cfg.Password)
require.Equal(t, base64, cfg.Auth)
})

t.Run("fail to match registry authentication due to invalid host", func(t *testing.T) {
Expand All @@ -135,8 +128,7 @@ func TestGetDockerConfig(t *testing.T) {
registry, cfg, err := DockerImageAuth(context.Background(), imageReg+imagePath)
require.ErrorIs(t, err, dockercfg.ErrCredentialsNotFound)
require.Empty(t, cfg)

assert.Equal(t, imageReg, registry)
require.Equal(t, imageReg, registry)
})

t.Run("fail to match registry authentication by host with empty URL scheme creds and missing default", func(t *testing.T) {
Expand All @@ -156,8 +148,7 @@ func TestGetDockerConfig(t *testing.T) {
registry, cfg, err := DockerImageAuth(context.Background(), imageReg+imagePath)
require.ErrorIs(t, err, dockercfg.ErrCredentialsNotFound)
require.Empty(t, cfg)

assert.Equal(t, imageReg, registry)
require.Equal(t, imageReg, registry)
})
}

Expand Down Expand Up @@ -391,27 +382,90 @@ func localAddress(t *testing.T) string {
var dockerConfig string

func Test_getDockerAuthConfigs(t *testing.T) {
t.Run("file", func(t *testing.T) {
got, err := getDockerAuthConfigs()
t.Run("HOME/valid", func(t *testing.T) {
testDockerConfigHome(t, "testdata")

requireValidAuthConfig(t)
})

t.Run("HOME/not-found", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "not-exist")

authConfigs, err := getDockerAuthConfigs()
require.NoError(t, err)
require.NotNil(t, got)
require.NotNil(t, authConfigs)
require.Empty(t, authConfigs)
})

t.Run("HOME/invalid-config", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "invalid-config")

authConfigs, err := getDockerAuthConfigs()
require.ErrorContains(t, err, "json: cannot unmarshal array")
require.Nil(t, authConfigs)
})

t.Run("env", func(t *testing.T) {
t.Run("DOCKER_AUTH_CONFIG/valid", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "not-exist")
t.Setenv("DOCKER_AUTH_CONFIG", dockerConfig)

got, err := getDockerAuthConfigs()
require.NoError(t, err)
requireValidAuthConfig(t)
})

// We can only check the keys as the values are not deterministic.
expected := map[string]registry.AuthConfig{
"https://index.docker.io/v1/": {},
"https://example.com": {},
"https://my.private.registry": {},
}
for k := range got {
got[k] = registry.AuthConfig{}
}
require.Equal(t, expected, got)
t.Run("DOCKER_AUTH_CONFIG/invalid-config", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "not-exist")
t.Setenv("DOCKER_AUTH_CONFIG", `{"auths": []}`)

authConfigs, err := getDockerAuthConfigs()
require.ErrorContains(t, err, "json: cannot unmarshal array")
require.Nil(t, authConfigs)
})

t.Run("DOCKER_CONFIG/valid", func(t *testing.T) {
testDockerConfigHome(t, "testdata", "not-found")
t.Setenv("DOCKER_CONFIG", filepath.Join("testdata", ".docker"))

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.
func requireValidAuthConfig(t *testing.T) {
t.Helper()

authConfigs, err := getDockerAuthConfigs()
require.NoError(t, err)

// We can only check the keys as the values are not deterministic as they depend
// on users environment.
expected := map[string]registry.AuthConfig{
"https://index.docker.io/v1/": {},
"https://example.com": {},
"https://my.private.registry": {},
}
for k := range authConfigs {
authConfigs[k] = registry.AuthConfig{}
}
require.Equal(t, expected, authConfigs)
}

// 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
}
3 changes: 3 additions & 0 deletions testdata/invalid-config/.docker/config.json
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
{
"auths": []
}

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