Principle:Apache Paimon Authentication

Knowledge Sources	Apache_Paimon
Domains	Authentication, Security
Last Updated	2026-02-08 00:00 GMT

Overview

Pluggable authentication framework for catalog access that supports multiple authentication methods including bearer tokens, signature-based auth, and cloud provider identity systems.

Description

Authentication in distributed data systems must support diverse identity providers and authentication mechanisms while presenting a uniform interface to catalog and storage operations. The authentication principle establishes a pluggable framework where different authentication strategies can be implemented and configured independently, allowing the same catalog implementation to work with various identity systems from cloud providers, enterprise directories, or custom authentication services.

The framework separates authentication concerns into discrete components including credential acquisition, token refresh, request signing, and identity propagation. Each authentication provider implements a common interface that produces credentials or signed requests compatible with the REST catalog protocol. This abstraction allows switching between authentication methods through configuration rather than code changes, enabling deployment flexibility across different environments with varying security requirements.

Authentication providers may obtain credentials through multiple channels including environment variables, configuration files, instance metadata services, or interactive credential prompts. Token-based authentication supports automatic refresh to handle expiration transparently, while signature-based authentication computes request signatures using secret keys and timestamp nonces to prove request authenticity. The framework handles edge cases like credential rotation, clock skew in signature validation, and fallback chains when primary authentication methods fail. Security-sensitive operations like token storage use secure memory handling to prevent credential leakage.

Usage

Apply this principle when building systems that must integrate with multiple identity providers, when security requirements vary across deployment environments, or when authentication mechanisms need to be extended without modifying core catalog logic. Use pluggable authentication when supporting multi-cloud deployments where each cloud provider has native identity services, or when enterprises require integration with existing authentication infrastructure.

Theoretical Basis

The authentication framework implements a strategy pattern with factory-based instantiation:

Authentication Provider Interface: ``` interface AuthProvider:

 method authenticate(request: HttpRequest) -> HttpRequest
 method refreshToken() -> Token
 method getHeaders() -> Map<String, String>

```

Factory Pattern for Provider Selection: ``` interface AuthProviderFactory:

 method create(config: Map<String, String>) -> AuthProvider
 method type() -> String

class AuthManager:

 factories: Map<String, AuthProviderFactory>

 method getProvider(type: String, config: Map) -> AuthProvider:
   factory = factories.get(type)
   if factory is null:
     throw UnknownAuthTypeException
   return factory.create(config)

```

Token-Based Authentication Flow: ``` 1. Provider loads initial token from configured source 2. Client includes token in Authorization header: "Bearer {token}" 3. Server validates token signature and expiration 4. On token expiration, provider refreshes:

  - Call token endpoint with refresh token
  - Store new access token and refresh token
  - Retry failed request with new token

```

Signature-Based Authentication Flow: ``` 1. Provider has access key ID and secret key 2. For each request:

  - Compute canonical request string (method, path, headers, body)
  - Generate signature: HMAC-SHA256(secret_key, canonical_request + timestamp)
  - Add headers: X-Auth-Key={key_id}, X-Auth-Signature={signature}, X-Auth-Timestamp={ts}

3. Server verifies:

  - Retrieve secret key for given key_id
  - Recompute signature using same algorithm
  - Verify signature matches and timestamp is within tolerance window

```

Cloud Provider Integration Pattern: For cloud services with instance metadata services: ``` 1. Provider queries metadata endpoint: http://169.254.169.254/latest/meta-data/iam/security-credentials/ 2. Endpoint returns temporary credentials:

  - Access key ID
  - Secret access key
  - Session token
  - Expiration time

3. Provider uses temporary credentials to sign requests 4. Background thread refreshes credentials before expiration ```

Authentication Chain: Multiple providers can be chained with fallback logic: ``` class ChainedAuthProvider:

 providers: List<AuthProvider>

 method authenticate(request):
   for provider in providers:
     try:
       return provider.authenticate(request)
     catch AuthException:
       continue
   throw NoAuthProviderSucceeded

```

This pattern allows trying instance metadata first, then environment variables, then configuration files, providing flexibility across deployment scenarios.

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