Plugin Authoring Guide

Plugin Authoring Guide

This guide shows how to build CCProxy plugins that integrate cleanly with the core and other plugins. It covers plugin types, structure, configuration, discovery, and best practices.

Plugin Types

Auth Provider Plugin (factory: AuthProviderPluginFactory)

• Provides standalone OAuth authentication without proxying requests
• Key Components: OAuth provider, token manager, secure storage, CLI integration
• Example: oauth_claude - provides Claude OAuth without API proxying
• Pattern: Extends AuthProviderPluginRuntime, registers OAuth provider in registry
• CLI Safe: cli_safe = True (safe for CLI usage)

Provider Plugin (factory: BaseProviderPluginFactory)

• Proxies API requests to external providers with full request/response lifecycle
• Key Components: HTTP adapter (delegation pattern), detection service, credentials manager, transformers, format adapters, hooks
• Example: codex - proxies OpenAI Codex API with format conversion and streaming metrics
• Pattern: Class-based configuration, declarative format adapters, streaming support
• CLI Safe: cli_safe = False (heavy provider - not for CLI)

System Plugin (factory: SystemPluginFactory)

• Adds system-wide functionality using hooks and services
• Key Components: Hooks for request lifecycle, services (analytics, pricing), routes for management APIs
• Example: access_log - hook-based request logging, analytics - provides query/ingest services
• Pattern: Hook-based architecture, service registration, background tasks

Use GET /plugins/status to see each plugin's type as auth_provider, provider, or system, along with initialization status, dependencies, and provided services.

Minimal Structure

• Manifest (static declaration): PluginManifest

  • name, version, description
  • is_provider: for provider and auth provider plugins
  • provides: service names this plugin provides (e.g., pricing)
  • requires: required services (hard fail if missing)
  • optional_requires: optional services
  • middleware: ordered by priority (see MiddlewareLayer)
  • routes: one or more APIRouters and prefixes
  • tasks: scheduled jobs registered with the scheduler
  • hooks: event subscribers
  • config_class: Pydantic model for plugin config (optional)

• Runtime: subclass of SystemPluginRuntime or ProviderPluginRuntime

  • Initialize from PluginContext (injected by core): settings, http_client, logger, scheduler, plugin_registry, request_tracer, streaming_handler, config, etc.
  • Register hooks/services/routes as needed.
  • Implement health_check, validate, and shutdown when applicable.

• Factory: subclass of the corresponding factory

  • Build PluginManifest
  • Create runtime
  • For providers, create adapter, detection_service, credentials_manager if applicable

Discovery

Plugins are discovered from two sources and merged:

• Local filesystem directories: each path listed in settings.plugin_discovery.directories (defaults to the bundled ccproxy/plugins folder and ${XDG_CONFIG_HOME}/ccproxy/plugins) is scanned for subfolders containing a plugin.py that exports factory (a PluginFactory).
• Installed entry points: Python packages that declare an entry under ccproxy.plugins providing a PluginFactory or a callable returning one.

Local filesystem plugins take precedence over entry points on name conflicts. To disable filesystem discovery and load plugins only from entry points, set plugins_disable_local_discovery = true in your .ccproxy.toml or export PLUGINS_DISABLE_LOCAL_DISCOVERY=true.

To add additional filesystem locations, declare them in configuration, e.g.:

[plugin_discovery]
directories = ["/opt/ccproxy/plugins", "${HOME}/.config/ccproxy/custom"]

Scaffolding New Plugins

Use the CLI scaffolder to generate starter files that follow these conventions:

uv run ccproxy plugins scaffold my_plugin --type provider --with-tests

• --type selects the template (system, provider, or auth).
• --path writes the plugin to a custom directory (defaults to your first writable discovery directory).
• --with-tests adds placeholder pytest smoke tests.
• --force overwrites an existing directory.

The scaffold includes configuration, runtime boilerplate, and a README listing next steps. Review and customize the generated files before enabling the plugin.

Declaring Entry Points (pyproject.toml)

[project.entry-points."ccproxy.plugins"]
my_plugin = "my_package.my_plugin:factory"
# or a callable that returns a PluginFactory
other_plugin = "my_package.other:create_factory"

Configuration

• Provide a config_class (Pydantic BaseModel) on the manifest.
• Core populates PluginContext["config"] with validated settings from:
  • Defaults < TOML config < Env (PLUGINS__{NAME}__FIELD) < CLI overrides
• Example env nest: PLUGINS__METRICS__ENABLED=true.

Routes & Middleware

• Add routes via RouteSpec(router=..., prefix=..., tags=[...]). Core mounts them with plugin-specific tags.
• Add middleware via MiddlewareSpec(middleware_class, priority=MiddlewareLayer.OBSERVABILITY, kwargs={...}).
• Keep handlers fast and non-blocking; use async I/O and avoid CPU-heavy work in request path.

Hooks

• Subscribe to events with HookSpec(hook_class=..., kwargs={...}).
• Common events are in HookEvent, e.g., REQUEST_STARTED, REQUEST_COMPLETED, PROVIDER_REQUEST_PREPARED, PROVIDER_STREAM_*.
• PROVIDER_REQUEST_PREPARED fires immediately before the upstream HTTP call; mutate context.data["body"], body_raw, or headers to tweak the provider request.
• Use hook priorities consistently. Avoid raising from hooks; log and continue.

Services

• Provide services by calling registry.register_service(name, instance, provider_plugin=name) from runtime.
• Consume services by calling registry.get_service(name, ExpectedType); returns None if absent.
• Avoid globals; rely on the plugin registry and container-managed clients.

Health & Status

• Implement health_check() in runtime to return IETF-style health.
• Check /plugins/status to inspect:
  • initialization_order (dependency order)
  • services map (service -> provider)
  • per-plugin summary (name, version, type, provides/requires, initialized)

Logging & Security

• Use structured logs via get_plugin_logger() or context-provided logger.
• Do not log secrets or sensitive request bodies. Mask tokens in logs.
• Respect repository logging conventions and levels.

Testing

• Use create_app(Settings(...)) + initialize_plugins_startup to bootstrap.
• Prefer httpx.ASGITransport for tests (no server needed).
• For timing-sensitive code, keep tests deterministic and avoid global registries.

Complete Plugin Examples

Provider Plugin with Format Conversion

# plugin.py (inside ccproxy/plugins/my_provider)
from ccproxy.core.plugins import (
    BaseProviderPluginFactory,
    ProviderPluginRuntime,
    PluginManifest,
    FormatAdapterSpec
)
from pydantic import BaseModel, Field
from fastapi import APIRouter

# Configuration
class MyProviderConfig(BaseModel):
    enabled: bool = Field(default=True)
    base_url: str = Field(default="https://api.example.com")
    supports_streaming: bool = Field(default=True)

# Router
router = APIRouter()

@router.post("/responses")
async def create_response(request: dict):
    # Provider-specific endpoint
    pass

# Runtime
class MyProviderRuntime(ProviderPluginRuntime):
    async def _on_initialize(self) -> None:
        """Initialize with format adapters and hooks."""
        config = self.context.get(MyProviderConfig)

        # Call parent (creates adapter, detection service)
        await super()._on_initialize()

        # Register streaming metrics hook
        if config.supports_streaming:
            await self._register_streaming_hook()

        logger.info("my_provider_initialized", enabled=config.enabled)

    async def _register_streaming_hook(self) -> None:
        """Register provider-specific streaming metrics hook."""
        hook_registry = self.context.get(HookRegistry)
        if hook_registry:
            hook = MyStreamingHook()
            hook_registry.register(hook)

# Factory with class-based configuration
class MyProviderFactory(BaseProviderPluginFactory):
    # Declarative configuration
    plugin_name = "my_provider"
    plugin_description = "My provider with streaming and format conversion"
    runtime_class = MyProviderRuntime
    adapter_class = MyProviderAdapter
    detection_service_class = MyDetectionService
    credentials_manager_class = MyCredentialsManager
    config_class = MyProviderConfig
    router = router
    route_prefix = "/api/my-provider"
    dependencies = ["oauth_my_provider"]
    optional_requires = ["pricing"]

    # Format adapter specifications
    format_adapters = [
        FormatAdapterSpec(
            from_format="openai",
            to_format="my_format",
            adapter_factory=lambda: MyFormatAdapter(),
            priority=40,
            description="OpenAI to My Provider conversion"
        )
    ]

# Export factory for discovery
factory = MyProviderFactory()

System Plugin with Hooks and Services

# plugin.py (inside ccproxy/plugins/my_system)
from ccproxy.core.plugins import (
    SystemPluginFactory,
    SystemPluginRuntime,
    PluginManifest,
    RouteSpec
)
from ccproxy.core.plugins.hooks import Hook, HookEvent, HookRegistry
from pydantic import BaseModel, Field
from fastapi import APIRouter

# Configuration
class MySystemConfig(BaseModel):
    enabled: bool = Field(default=True)
    buffer_size: int = Field(default=100)

# Routes
router = APIRouter()

@router.get("/status")
async def get_status():
    return {"status": "active"}

# Hook implementation
class MySystemHook(Hook):
    name = "my_system"
    events = [HookEvent.REQUEST_STARTED, HookEvent.REQUEST_COMPLETED]
    priority = 750

    def __init__(self, config: MySystemConfig):
        self.config = config
        self.buffer = []

    async def __call__(self, context: HookContext) -> None:
        if context.event == HookEvent.REQUEST_STARTED:
            # Process request start
            self._buffer_request_data(context.data)
        elif context.event == HookEvent.REQUEST_COMPLETED:
            # Process completion with metrics
            self._buffer_completion_data(context)

# Service implementation
class MySystemService:
    def __init__(self, config: MySystemConfig):
        self.config = config

    def process_data(self, data: dict) -> dict:
        # Service logic
        return data

# Runtime
class MySystemRuntime(SystemPluginRuntime):
    def __init__(self, manifest: PluginManifest):
        super().__init__(manifest)
        self.hook = None
        self.service = None
        self.config = None

    async def _on_initialize(self) -> None:
        """Initialize hooks and services."""
        if not self.context:
            raise RuntimeError("Context not set")

        # Get configuration
        config = self.context.get("config")
        if not isinstance(config, MySystemConfig):
            config = MySystemConfig()
        self.config = config

        if not config.enabled:
            return

        # Create and register hook
        self.hook = MySystemHook(config)
        hook_registry = self.context.get(HookRegistry)
        if hook_registry:
            hook_registry.register(self.hook)

        # Create and register service
        self.service = MySystemService(config)
        plugin_registry = self.context.get("plugin_registry")
        if plugin_registry:
            plugin_registry.register_service(
                "my_service", self.service, self.manifest.name
            )

        logger.info("my_system_initialized")

    async def _on_shutdown(self) -> None:
        """Cleanup resources."""
        if self.hook:
            # Hook cleanup
            await self.hook.close()

# Factory
class MySystemFactory(SystemPluginFactory):
    def __init__(self) -> None:
        manifest = PluginManifest(
            name="my_system",
            version="1.0.0",
            description="My system plugin with hooks and services",
            is_provider=False,
            config_class=MySystemConfig,
            provides=["my_service"],
            dependencies=["analytics"],
            routes=[
                RouteSpec(
                    router=router,
                    prefix="/my-system",
                    tags=["my-system"]
                )
            ]
        )
        super().__init__(manifest)

    def create_runtime(self) -> MySystemRuntime:
        return MySystemRuntime(self.manifest)

# Export factory
factory = MySystemFactory()

Publishing

• Package your plugin and declare the ccproxy.plugins entry point in pyproject.toml.
• Version it semantically and document configuration fields and routes.

Best Practices

• Keep adapters and detection logic small and focused.
• Use the container-managed HTTP client; never create your own long-lived clients.
• Avoid global singletons; favor dependency injection via the container and plugin registry.
• Ensure hooks and tasks fail gracefully; log errors without breaking the app.
• Write minimal, clear tests; keep integration tests fast.

See also:

• docs/PLUGIN_SYSTEM_DOCUMENTATION.md for more on the plugin runtime model
• Metrics/logging plugins (e.g., plugins/metrics, plugins/analytics) for observability patterns
• GET /plugins/status for runtime inspection