typenames.witx

;; Type names used by Envoy ABI.
;;
;; This is a `witx` file. See [here](https://github.com/WebAssembly/WASI/tree/master/docs/witx.md)
;; for an explanation of what that means.

;;; Error codes returned by ABI functions.
(typename $wasm_result
  (enum u32
    ;;; No error occurred. ABI call completed successfully.
    $ok
    ;;; The result could not be found, e.g. a provided key did not appear in a table.
    $not_found
    ;;; An argument was bad, e.g. did not conform to the required range.
    $bad_argument
    ;;; A protobuf could not be serialized.
    $serialization_failure
    ;;; A protobuf could not be parsed.
    $parse_failure
    ;;; A provided expression (e.g. "foo.bar") was illegal or unrecognized.
    $bad_expression
    ;;; A provided memory range was not legal.
    $invalid_memory_access
    ;;; Data was requested from an empty container.
    $empty
    ;;; The provided CAS did not match that of the stored data.
    $cas_mismatch
    ;;; Returned result was unexpected, e.g. of the incorrect size.
    $result_mismatch
    ;;; Internal failure: trying check logs of the surrounding system.
    $internal_failure
    ;;; The connection/stream/pipe was broken/closed unexpectedly.
    $broken_connection
  )
)

;;; Peer type.
(typename $peer_type
  (enum u32
    ;;; Unknown.
    $unknown
    ;;; Local.
    $local
    ;;; Remote.
    $remote
  )
)

;;; Status codes returned by filters that can cause future filters to not get iterated to.
(typename $filter_status
  (enum u32
    ;;; Continue to further filters.
    $continue
    ;;; Stop executing further filters.
    $stop_iteration
  )
)

;;; Return codes for encode/decode headers filter invocations. The connection manager bases further
;;; filter invocations on the return code of the previous filter.
(typename $filter_headers_status
  (enum u32
    ;;; Continue filter chain iteration.
    $continue
    ;;; Do not iterate to any of the remaining filters in the chain. Returning
    ;;; FilterDataStatus::Continue from decodeData()/encodeData() or calling
    ;;; continueDecoding()/continueEncoding() MUST be called if continued filter iteration is desired.
    $stop_iteration

    ;;; TODO(up-to-date): Envoy API (include/envoy/http) has more variants than Envoy ABI (api/wasm/cpp)
  )
)

;;; Return codes for encode/decode data filter invocations. The connection manager bases further
;;; filter invocations on the return code of the previous filter.
(typename $filter_data_status
  (enum u32
    ;;; Continue filter chain iteration. If headers have not yet been sent to the next filter, they
    ;;; will be sent first via decodeHeaders()/encodeHeaders(). If data has previously been buffered,
    ;;; the data in this callback will be added to the buffer before the entirety is sent to the next
    ;;; filter.
    $continue
    ;;; Do not iterate to any of the remaining filters in the chain, and buffer body data for later
    ;;; dispatching. Returning FilterDataStatus::Continue from decodeData()/encodeData() or calling
    ;;; continueDecoding()/continueEncoding() MUST be called if continued filter iteration is desired.
    ;;;
    ;;; This should be called by filters which must parse a larger block of the incoming data before
    ;;; continuing processing and so can not push back on streaming data via watermarks.
    ;;;
    ;;; If buffering the request causes buffered data to exceed the configured buffer limit, a 413 will
    ;;; be sent to the user. On the response path exceeding buffer limits will result in a 500. 
    $stop_iteration_and_buffer
    ;;; Do not iterate to any of the remaining filters in the chain, and buffer body data for later
    ;;; dispatching. Returning FilterDataStatus::Continue from decodeData()/encodeData() or calling
    ;;; continueDecoding()/continueEncoding() MUST be called if continued filter iteration is desired.
    ;;;
    ;;; This will cause the flow of incoming data to cease until one of the continue.*() functions is
    ;;; called.
    ;;;
    ;;; This should be returned by filters which can nominally stream data but have a transient back-up
    ;;; such as the configured delay of the fault filter, or if the router filter is still fetching an
    ;;; upstream connection.
    $stop_iteration_and_watermark
    ;;; Do not iterate to any of the remaining filters in the chain, but do not buffer any of the
    ;;; body data for later dispatching. Returning FilterDataStatus::Continue from
    ;;; decodeData()/encodeData() or calling continueDecoding()/continueEncoding() MUST be called if
    ;;; continued filter iteration is desired.
    $stop_iteration_no_buffer
  )
)

;;; Return codes for encode/decode trailers filter invocations. The connection manager bases further
;;; filter invocations on the return code of the previous filter.
(typename $filter_trailers_status
  (enum u32
    ;;; Continue filter chain iteration.
    $continue
    ;;; Do not iterate to any of the remaining filters in the chain. Calling
    ;;; continueDecoding()/continueEncoding() MUST be called if continued filter iteration is desired.
    $stop_iteration
  )
)

;;; Return codes for encode metadata filter invocations. Metadata currently can not stop filter
;;; iteration.
(typename $filter_metadata_status
  (enum u32
    ;;; Continue filter chain iteration.
    $continue
  )
)

;;; Type of a header map.
(typename $headers_type
  (enum u32
    ;;; Request headers of a proxied HTTP request.
    $request_headers
    ;;; Request trailers of a proxied HTTP request.
    $request_trailers
    ;;; Response headers of a proxied HTTP request.
    $response_headers
    ;;; Response trailers of a proxied HTTP request.
    $response_trailers
    ;;; Client's initial metadata of an outgoing gRPC call.
    $grpc_create_initial_metadata
    ;;; Server's initial metadata of an outgoing gRPC call.
    $grpc_receive_initial_metadata
    ;;; Server's trailing metadata of an outgoing gRPC call.
    $grpc_receive_trailing_metadata
    ;;; Response headers of an outgoing HTTP request.
    $http_call_response_headers
    ;;; Response trailers of an outgoing HTTP request.
    $http_call_response_trailers
  )
)

;;; Type of payload in a buffer.
(typename $buffer_type
  (enum u32
    ;;; Request body of a proxied HTTP request.
    $http_request_body
    ;;; Response body of a proxied HTTP request.
    $http_response_body
    ;;; Request payload of a proxied L4 connection.
    $network_downstream_data
    ;;; Response payload of a proxied L4 connection.
    $network_upstream_data
    ;;; Response body of an outgoing HTTP request.
    $http_call_response_body
    ;;; Response payload of an outgoing gRPC call.
    $grpc_receive_buffer
  )
)

;;; Buffer flags.
(typename $buffer_flags
  (flags u32
    ;;; End of stream has been reached.
    $end_of_stream
  )
)

;;; Size of data in a linear memory.
(typename $size u32)

;;; Size of a header map, e.g. request headers, response trailers, etc.
(typename $map_size u32)

;;; Unique identifier of a root/connection/request context.
(typename $context_id (handle))

;;; Opaque identifier of an outgoing HTTP request, gRPC call, etc.
(typename $token (handle))

;;; Metric handle.
(typename $metric_id (handle))

;;; Metric type.
(typename $metric_type
  (enum u32
    ;;; Counter.
    $counter
    ;;; Gauge.
    $gauge
    ;;; Histogram.
    $histogram
  )
)

;;; Boolean true or false.
(typename $boolean u32)

;;; Timestamp in nanoseconds.
(typename $timestamp u64)

;;; Well-known gRPC statuses.
(typename $grpc_status
  ;;; notice that Envoy C ABI uses `int32_t` type, but `witx` doesn't allow to use `s32` for `enum`
  (enum u32
    ;;; The RPC completed successfully.
    $ok
    ;;; The RPC was canceled.
    $canceled
    ;;; Some unknown error occurred.
    $unknown
    ;;; An argument to the RPC was invalid.
    $invalid_argument
    ;;; The deadline for the RPC expired before the RPC completed.
    $deadline_exceeded
    ;;; Some resource for the RPC was not found.
    $not_found
    ;;; A resource the RPC attempted to create already exists.
    $already_exists
    ;;; Permission was denied for the RPC.
    $permission_denied
    ;;; Some resource is exhausted, resulting in RPC failure.
    $resource_exhausted
    ;;; Some precondition for the RPC failed.
    $failed_precondition
    ;;; The RPC was aborted.
    $aborted
    ;;; Some operation was requested outside of a legal range.
    $out_of_range
    ;;; The RPC requested was not implemented.
    $unimplemented
    ;;; Some internal error occurred.
    $internal
    ;;; The RPC endpoint is current unavailable.
    $unavailable
    ;;; There was some data loss resulting in RPC failure.
    $data_loss
    ;;; The RPC does not have required credentials for the RPC to succeed.
    $unauthenticated

    ;;; This is a non-GRPC error code, indicating the status code in gRPC headers
    ;;; was invalid.
    $invalid_code
  )
)

;;; Log level.
(typename $log_level
  (enum u32
    ;;; Trace.
    $trace
    ;;; Debug.
    $debug
    ;;; Info.
    $info
    ;;; Warn.
    $warn
    ;;; Error.
    $error
    ;;; Critical.
    $critical
  )
)