Packages

  • package root
    Definition Classes
    root
  • package com

    Start with com.twitter.finagle.

    Definition Classes
    root
  • package twitter

    Start with com.twitter.finagle.

    Definition Classes
    com
  • package finagle

    Finagle is an extensible RPC system.

    Finagle is an extensible RPC system.

    Services are represented by class com.twitter.finagle.Service. Clients make use of com.twitter.finagle.Service objects while servers implement them.

    Finagle contains a number of protocol implementations; each of these implement Client and/or com.twitter.finagle.Server. For example, Finagle's HTTP implementation, com.twitter.finagle.Http (in package finagle-http), exposes both.

    Thus a simple HTTP server is built like this:

    import com.twitter.finagle.{Http, Service}
    import com.twitter.finagle.http.{Request, Response}
    import com.twitter.util.{Await, Future}
    
    val service = new Service[Request, Response] {
      def apply(req: Request): Future[Response] =
        Future.value(Response())
    }
    val server = Http.server.serve(":8080", service)
    Await.ready(server)

    We first define a service to which requests are dispatched. In this case, the service returns immediately with a HTTP 200 OK response, and with no content.

    This service is then served via the Http protocol on TCP port 8080. Finally we wait for the server to stop serving.

    We can now query our web server:

    % curl -D - localhost:8080
    HTTP/1.1 200 OK

    Building an HTTP client is also simple. (Note that type annotations are added for illustration.)

    import com.twitter.finagle.{Http, Service}
    import com.twitter.finagle.http.{Request, Response}
    import com.twitter.util.{Future, Return, Throw}
    
    val client: Service[Request, Response] = Http.client.newService("localhost:8080")
    val f: Future[Response] = client(Request()).respond {
      case Return(rep) =>
        printf("Got HTTP response %s\n", rep)
      case Throw(exc) =>
        printf("Got error %s\n", exc)
    }

    Http.client.newService("localhost:8080") constructs a new com.twitter.finagle.Service instance connected to localhost TCP port 8080. We then issue a HTTP/1.1 GET request to URI "/". The service returns a com.twitter.util.Future representing the result of the operation. We listen to this future, printing an appropriate message when the response arrives.

    The Finagle homepage contains useful documentation and resources for using Finagle.

    Definition Classes
    twitter
  • package addr
    Definition Classes
    finagle
  • package builder
    Definition Classes
    finagle
  • package client
    Definition Classes
    finagle
  • package context
    Definition Classes
    finagle
  • package core
    Definition Classes
    finagle
  • package dispatch
    Definition Classes
    finagle
  • package exception
    Definition Classes
    finagle
  • package exp

    Package exp contains experimental code.

    Package exp contains experimental code. This can be removed or stabilized (moved elsewhere) at any time.

    Definition Classes
    finagle
  • package factory
    Definition Classes
    finagle
  • package filter
    Definition Classes
    finagle
  • DtabStatsFilter
  • ExceptionSourceFilter
  • LogFormatter
  • LoggingFilter
  • MaskCancelFilter
  • MkJvmFilter
  • MonitorFilter
  • RequestMeterFilter
  • RequestSemaphoreFilter
  • package group
    Definition Classes
    finagle
  • package http
    Definition Classes
    finagle
  • package http2
    Definition Classes
    finagle
  • package httpproxy
    Definition Classes
    finagle
  • package kestrel
    Definition Classes
    finagle
  • package loadbalancer

    This package implements client side load balancing algorithms.

    This package implements client side load balancing algorithms.

    As an end-user, see the Balancers API to create instances which can be used to configure a Finagle client with various load balancing strategies.

    As an implementor, each algorithm gets its own subdirectory and is exposed via the Balancers object. Several convenient traits are provided which factor out common behavior and can be mixed in (i.e. Balancer, DistributorT, NodeT, and Updating).

    Definition Classes
    finagle
  • package mdns
    Definition Classes
    finagle
  • package memcached
    Definition Classes
    finagle
  • package mux

    Package mux implements a generic RPC multiplexer with a rich protocol.

    Package mux implements a generic RPC multiplexer with a rich protocol. Mux is itself encoding independent, so it is meant to use as the transport for other RPC systems (eg. thrift). In OSI terminology, it is a pure session layer.

    In the below description, all numeric values are unsigned and in big-endian byte order. The schema size:4 body:10 defines the field size to be 4 bytes, followed by 10 bytes of the field body. The schema key~4 defines the field key to be defined by 4 bytes interpreted as the size of the field, followed by that many bytes comprising the field itself--it is shorthand for keysize:4 key:keysize. Groups are denoted by parenthesis; * denotes repetition of the previous schema 0 or more times, while {n} indicates repetition exactly n times. Unspecified sizes consume the rest of the frame: they may be specified only as the last field in the message.

    All strings in Mux are Utf-8 encoded, and are never null-terminated.

    Message framing

    Messages in mux are framed with a 4-byte big-endian size header, followed by 1 byte describing the message type and a 3-byte tag; or, diagrammatically: size:4 type:1 tag:3. The remainder of the frame (size-4 bytes) contains the body. Its format depends on the message type, documented below.

    Tag 0 designates a "marker" T message that expects no reply. Some messages may be split into an ordered sequence of fragments. Tag MSB=0 denotes the last message in such a sequence, making the tag namespace 23 bits. The tag is otherwise arbitrary, and is chosen by the sender of the T message.

    Currently, only Tdispatch and Rdispatch messages may be split into an ordered sequence of fragments. TdispatchError message ends a Tdispatch sequence and an Rerr ends an Rdispatch sequence.

    Message types, interpreted as a two's complement, 1-byte integer are numbered as follows: positive numbers are T-messages; their negative complement is the corresponding R message. T-messages greater than 63 (correspondingly R-messages smaller than -63) are session messages. The message number -128 is reserved for Rerr. All other messages are application messages. Middle boxes may forward application messages indiscriminately. Because of an early implementation bug, two aliases exist: 127 is Rerr, and -62 is Tdiscarded.

    The protocol is full duplex: both the server and client may send T messages initiating an exchange.

    Exchanges

    Messages are designated as "T messages" or "R messages", T and R being stand-ins for transmit and receive. A T message initiates an exchange and is assigned a free tag by the sender. A reply is either an R message of the same type (Rx replies to Tx for some x), or an Rerr, indicating a session layer error. R messages are matched to their T messages by tag, and the reply concludes the exchange and frees the tag for future use. Implementations should reuse small tag numbers.

    Messages

    size:4 Tinit:1 tag:3 version:2 (key~4 value~4)* reinitializes a session. Clients typically send this at the beginning of the session. When doing so, the sender may issue no more T messages until the corresponding size:4 Rinit:1 tag:3 version:2 (key~4 value~4)* has been received. After the Rinit was received, all connection state has been reset (outstanding tags are invalidated) and the stream is resumed according to the newly negotiated parameters. Prior to the first Tinit, the session operates at version 1. Rinit's version field is the accepted version of the session (which may be lower than the one requested by Tinit).

    size:4 Treq:1 tag:3 n:1 (key:1 value~1){n} body: initiates the request described by its body. The request body is delivered to the application. The request header contains a number of key-value pairs that describe request metadata.

    Keys for Treq messages are as follows:

    1. traceid: a 24-byte value describing the full Dapper trace id assigned by the client. The value's format is spanid:8 parentid:8 traceid:8.

    2. traceflag: a bitmask describing trace flags. Currently, the only defined flag is bit 0 which enables "debug mode", asking the server to force trace sampling.

    size:4 Tdispatch:1 tag:3 nctx:2 (ckey~2 cval~2){nc} dst~2 nd:2 (from~2 to~2){nd} body: implements destination dispatch. Tdispatch messages carry a set of keyed request contexts, followed by a logical destination encoded as a UTF-8 string. A delegation table follows describing rewrite rules that apply to this request.

    size:4 Rreq:1 tag:3 status:1 body: replies to a request. Status codes are as follows: 0=OK; the body contains the reply. 1=ERROR; the body contains a string describing the error. 2=NACK; a negative acknowledgment, the body contains a string describing the reason.

    size:4 Rdispatch:1 tag:3 status:1 nctx:2 (key~2 value~2){nctx} body: replies to a Tdispatch request. Status codes are as in Rreq. Replies can include request contexts. MuxFailure flags are currently sent via Rdispatch contexts under the "MuxFailure" key. See the MuxFailure flags section below.

    size:4 Rerr:1 tag:3 why: indicates that the corresponding T message produced an error. Rerr is specifically for server errors: the server failed to interpret or act on the message. The body carries a string describing the error.

    size:4 Tdrain:1 tag:3 is a request sent by the server telling the client to stop sending new requests. A client acknowledges this with an Rdrain message.

    size:4 Tping:1 tag:3 is sent by either party to check the liveness of its peer; these should be responded to immediately with a Rping message.

    size:4 Tdiscarded:1 tag:3 discard_tag:3 why: is a marker message and therefore has a tag value of 0. discard_tag indicates the tag of the Tdispatch to be discarded by the client. This can be used as a hint for early termination. Why is a string describing why the request was discarded. Note that it does *not* free the server from the obligation of replying to the original Treq.

    size:4 Tlease:1 tag:3 unit:1 howmuch:8 is a marker message indicating that a lease has been issued for howmuch units. As a marker message, its tag value must be 0. Unit '0' is reserved for duration in milliseconds. Whenever a lease has not been issued, a client can assume it holds an indefinite lease. Adhering to the lease is optional, but the server may reject requests or provide degraded service should the lease expire. This is used by servers to implement features like garbage collection avoidance.

    MuxFailure Flags

    Failure flags are read and written as an 8 byte integer. Unrecognized flags will be ignored silently, but should all be considered reserved for future use.

    Flag Value Meaning Restartable 1 << 0 Request is safe to re-issue Rejected 1 << 1 Request was rejected/Nacked by the server NonRetryable 1 << 2 Request should not be retried

    Definition Classes
    finagle
  • package mysql
    Definition Classes
    finagle
  • package namer
    Definition Classes
    finagle
  • package naming
    Definition Classes
    finagle
  • package netty3

    Package netty3 implements the bottom finagle primitives: {{com.twitter.finagle.Server}} and a client transport in terms of the netty3 event loop.

    Package netty3 implements the bottom finagle primitives: {{com.twitter.finagle.Server}} and a client transport in terms of the netty3 event loop.

    Note: when {{com.twitter.finagle.builder.ClientBuilder}} and {{com.twitter.finagle.builder.ServerBuilder}} are deprecated, package netty3 can move into its own package, so that only the (new-style) clients and servers that depend on netty3 bring it in.

    Definition Classes
    finagle
  • package netty4

    Package netty4 implements the bottom finagle primitives: com.twitter.finagle.Server and a client transport in terms of the netty4 event loop.

    Package netty4 implements the bottom finagle primitives: com.twitter.finagle.Server and a client transport in terms of the netty4 event loop.

    Definition Classes
    finagle
  • package param

    Defines common com.twitter.finagle.Stack.Param's shared between finagle clients and servers.

    Defines common com.twitter.finagle.Stack.Param's shared between finagle clients and servers.

    Definition Classes
    finagle
  • package pool
    Definition Classes
    finagle
  • package redis
    Definition Classes
    finagle
  • package server
    Definition Classes
    finagle
  • package serverset2
    Definition Classes
    finagle
  • package service
    Definition Classes
    finagle
  • package socks
    Definition Classes
    finagle
  • package ssl
    Definition Classes
    finagle
  • package stats
    Definition Classes
    finagle
  • package stream

    Finagle-stream implements a rather peculiar protocol: it streams discrete messages delineated by HTTP chunks.

    Finagle-stream implements a rather peculiar protocol: it streams discrete messages delineated by HTTP chunks. It isn't how we'd design a protocol to stream messages, but we are stuck with it for legacy reasons.

    Finagle-stream sessions are also one-shot: each session handles exactly one stream. The session terminates together with the stream.

    Definition Classes
    finagle
  • package thrift

    Please use the new interface, com.twitter.finagle.Thrift, for constructing Thrift clients and servers.

    Deprecation

    Please use the new interface, com.twitter.finagle.Thrift, for constructing Thrift clients and servers.

    Thrift codecs

    We provide client and server protocol support for the framed protocol. The public implementations are defined on the Thrift object:

    The type of the server codec is Service[Array[Byte], Array[Byte]] and the client codecs are Service[ThriftClientRequest, Array[Byte]]. The service provided is that of a "transport" of thrift messages (requests and replies) according to the protocol chosen. This is why the client codecs need to have access to a thrift ProtocolFactory.

    These transports are used by the services produced by the finagle thrift codegenerator.

    val service: Service[ThriftClientRequest, Array[Byte]] = ClientBuilder()
      .hosts("foobar.com:123")
      .stack(Thrift.client)
      .build()
    
    // Wrap the raw Thrift transport in a Client decorator. The client
    // provides a convenient procedural interface for accessing the Thrift
    // server.
    val client = new Hello.ServiceToClient(service, protocolFactory)

    In this example, Hello is the thrift interface, and the inner class ServiceToClient is provided by the finagle thrift code generator.

    Definition Classes
    finagle
  • package thriftmux
    Definition Classes
    finagle
  • package toggle
    Definition Classes
    finagle
  • package tracing
    Definition Classes
    finagle
  • package transport
    Definition Classes
    finagle
  • package util
    Definition Classes
    finagle
  • package zipkin
    Definition Classes
    finagle
  • package zookeeper
    Definition Classes
    finagle

package filter

Ordering
  1. Alphabetic
Visibility
  1. Public
  2. All

Type Members

  1. class DtabStatsFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    Adds a Stat, dtab/local/size, that tracks the size of Dtab.local for all requests with a non-empty Dtab.

  2. class ExceptionSourceFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that sources exceptions.

    A com.twitter.finagle.Filter that sources exceptions. The serviceName field of any com.twitter.finagle.SourcedException thrown by the underlying com.twitter.finagle.Service is set to the serviceName argument of this filter.

  3. trait LogFormatter [-Req, Rep] extends AnyRef
  4. trait LoggingFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that logs all requests according to formatter.

  5. class MaskCancelFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that prevents cancellations from propagating to any subsequent Services.

    A com.twitter.finagle.Filter that prevents cancellations from propagating to any subsequent Services. i.e. when Future.raise is invoked on the result of this filter's apply method, the interrupt will not be propagated to the service. This is useful for lightweight protocols for which finishing a request is preferable to closing and reesstablishing a connection.

  6. class MkJvmFilter extends AnyRef

    Given a Jvm, create filters to record GCs (and other JVM events in the future).

  7. class MonitorFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that handles exceptions (incl.

    A com.twitter.finagle.Filter that handles exceptions (incl. raw) thrown by the subsequent com.twitter.finagle.Service. Exceptions are handled according to the argument com.twitter.util.Monitor.

  8. class RequestMeterFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that rate limits requests to a fixed rate over time by using the com.twitter.concurrent.AsyncMeter implementation.

    A com.twitter.finagle.Filter that rate limits requests to a fixed rate over time by using the com.twitter.concurrent.AsyncMeter implementation. It can be used for slowing down access to throttled resources. Requests that cannot be enqueued to await a permit are failed immediately with a com.twitter.finagle.Failure that signals that the work was never done, so it's safe to reenqueue.

    NOTE: If you're just trying not to be overwhelmed, you almost certainly want to use com.twitter.finagle.filter.RequestSemaphoreFilter instead, because RequestMeterFilter doesn't work well with "real" resources that are sometimes faster or slower (like a service that you're depending on that sometimes slows when it takes bursty traffic). This is better for resources that are artificially bounded, like a rate-limited API.

  9. class RequestSemaphoreFilter [Req, Rep] extends SimpleFilter[Req, Rep]

    A com.twitter.finagle.Filter that restricts request concurrency according to the given com.twitter.concurrent.AsyncSemaphore.

    A com.twitter.finagle.Filter that restricts request concurrency according to the given com.twitter.concurrent.AsyncSemaphore. Requests that are unable to acquire a permit are failed immediately with a com.twitter.finagle.Failure that signals a restartable or idempotent process.

    See also

    The user guide for more details.

Ungrouped