parseDockerAuthConfig function

List<DockerAuthInfo>? parseDockerAuthConfig(String authConfig)

Parses a JSON Docker config.json-style auth configuration string.

The expected format mirrors what docker login writes into ~/.docker/config.json:

{
  "auths": {
    "https://index.docker.io/v1/": {
      "auth": "<base64(username:password)>"
    }
  }
}

Behaviour:

• Returns a List<DockerAuthInfo> with one entry per registry found under the auths key. The list is unmodifiable.
• Returns null when the auths key is absent.
• Returns an empty list when auths is present but contains no entries.
• Emits a one-time warning to stderr when credHelpers or credsStore keys are present, because those external credential helpers are not yet supported.

Parameters:

• authConfig — the raw JSON string from DOCKER_AUTH_CONFIG.

Throws ArgumentError if authConfig is not valid JSON or the auth value cannot be base64-decoded.

Implementation

List<DockerAuthInfo>? parseDockerAuthConfig(String authConfig) {
  try {
    final Map<String, dynamic> config =
        jsonDecode(authConfig) as Map<String, dynamic>;

    if (config.containsKey('credHelpers') && _credHelpersWarning != null) {
      stderr.writeln(_credHelpersWarning);
      _credHelpersWarning = null;
    }
    if (config.containsKey('credsStore') && _credsStoreWarning != null) {
      stderr.writeln(_credsStoreWarning);
      _credsStoreWarning = null;
    }

    final auths = config['auths'] as Map<String, dynamic>?;
    if (auths == null) {
      return null;
    }

    final result = <DockerAuthInfo>[];
    for (final entry in auths.entries) {
      final authEntry = entry.value as Map<String, dynamic>;
      final authStr = utf8.decode(base64.decode(authEntry['auth'] as String));
      final colonIdx = authStr.indexOf(':');
      if (colonIdx < 0) {
        stderr.writeln(
          'testcontainers: skipping auth entry for registry '
          '"${entry.key}" — decoded credentials contain no colon separator.',
        );
        continue;
      }
      result.add(
        (
          registry: entry.key,
          username: authStr.substring(0, colonIdx),
          password: authStr.substring(colonIdx + 1),
        ),
      );
    }
    return List.unmodifiable(result);
  } on FormatException catch (e) {
    throw ArgumentError('Could not parse docker auth config: $e');
  } on TypeError catch (e) {
    throw ArgumentError('Unexpected structure in docker auth config: $e');
  }
}