Callout Server

This module provides a customizable service callout server with support for header and body transformations.

Class Definition

class callouts.python.extproc.service.callout_server.CalloutServer(address: tuple[str, int] | None = None, port: int | None = None, health_check_address: tuple[str, int] | None = None, health_check_port: int | None = None, combined_health_check: bool = False, secure_health_check: bool = False, plaintext_address: tuple[str, int] | None = None, plaintext_port: int | None = None, disable_plaintext: bool = False, default_ip: str | None = None, cert_chain: bytes | None = None, cert_chain_path: str | None = './extproc/ssl_creds/chain.pem', private_key: bytes | None = None, private_key_path: str = './extproc/ssl_creds/privatekey.pem', server_thread_count: int = 2)[source]

Bases: object

Server wrapper for managing callout servers and processing callouts.

address

Address that the main secure server will attempt to connect to, defaults to default_ip:443.

port

If specified, overrides the port of address.

health_check_address

The health check serving address, defaults to default_ip:80.

health_check_port

If set, overrides the port of health_check_address.

combined_health_check

If True, does not create a separate health check server.

secure_health_check

If True, will use HTTPS as the protocol of the health check server. Requires cert_chain_path and private_key_path to be set.

plaintext_address

The non-authenticated address to listen to, defaults to default_ip:8080.

plaintext_port

If set, overrides the port of plaintext_address.

disable_plaintext

If true, disables the plaintext address of the server.

default_ip

If left None, defaults to ‘0.0.0.0’.

cert_chain

PEM Certificate chain used to authenticate secure connections, required for secure servers.

cert_chain_path

Relative file path to the cert_chain.

private_key

PEM private key of the server.

private_key_path

Relative file path pointing to a file containing private_key data.

server_thread_count

Threads allocated to the main grpc service.

CalloutServer Methods

CalloutServer.run() → None[source]

Start all requested servers and listen for new connections; blocking.

CalloutServer.shutdown() → None[source]

Tell the server to shutdown, ending all serving threads.

CalloutServer._start_servers() → None[source]

Start the requested servers.

CalloutServer._stop_servers() → None[source]

Close the sockets of all servers, and trigger shutdowns.

CalloutServer._loop_server() → None[source]

Loop server forever, calling shutdown will cause the server to stop.

CalloutServer.process(callout: envoy.service.ext_proc.v3.external_processor_pb2.ProcessingRequest, context: ServicerContext) → envoy.service.ext_proc.v3.external_processor_pb2.ProcessingResponse[source]

Process incomming callouts.

Parameters:

  • callout – The incomming callout.

  • context – Stream context on the callout.

Yields:

ProcessingResponse – A response for the incoming callout.

CalloutServer.on_request_headers(headers: envoy.service.ext_proc.v3.external_processor_pb2.HttpHeaders, context: ServicerContext) → None | envoy.service.ext_proc.v3.external_processor_pb2.HeadersResponse | envoy.service.ext_proc.v3.external_processor_pb2.ImmediateResponse[source]

Process incoming request headers.

Parameters:

  • headers – Request headers to process.

  • context – RPC context of the incoming callout.

Returns:

Optional header modification object.

CalloutServer.on_response_headers(headers: envoy.service.ext_proc.v3.external_processor_pb2.HttpHeaders, context: ServicerContext) → None | envoy.service.ext_proc.v3.external_processor_pb2.HeadersResponse[source]

Process incoming response headers.

Parameters:

  • headers – Response headers to process.

  • context – RPC context of the incoming callout.

Returns:

Optional header modification object.

CalloutServer.on_request_body(body: envoy.service.ext_proc.v3.external_processor_pb2.HttpBody, context: ServicerContext) → None | envoy.service.ext_proc.v3.external_processor_pb2.BodyResponse | envoy.service.ext_proc.v3.external_processor_pb2.ImmediateResponse[source]

Process an incoming request body.

Parameters:

  • headers – Request body to process.

  • context – RPC context of the incoming callout.

Returns:

Optional body modification object.

CalloutServer.on_response_body(body: envoy.service.ext_proc.v3.external_processor_pb2.HttpBody, context: ServicerContext) → None | envoy.service.ext_proc.v3.external_processor_pb2.BodyResponse[source]

Process an incoming response body.

Parameters:

  • headers – Response body to process.

  • context – RPC context of the incoming callout.

Returns:

Optional body modification object.

HealthCheckService Class

class callouts.python.extproc.service.callout_server.HealthCheckService(request, client_address, server)[source]

Bases: BaseHTTPRequestHandler

Server for responding to health check pings.

do_GET() → None[source]

Returns an empty page with 200 status code.

GRPC Callout Service

class callouts.python.extproc.service.callout_server._GRPCCalloutService(*args: Any, **kwargs: Any)[source]

Bases: ExternalProcessorServicer

GRPC based Callout server implementation.

Process(callout_iterator: Iterable[envoy.service.ext_proc.v3.external_processor_pb2.ProcessingRequest], context: ServicerContext) → Iterator[envoy.service.ext_proc.v3.external_processor_pb2.ProcessingResponse][source]

Process the client callout.