Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / grpc-grpc / f423280a90a34cd04ec3cf34eaeb18cff83aad10
commitf423280a90a34cd04ec3cf34eaeb18cff83aad10[log] [tgz]
authorkpayson64 <kpayson@google.com>Mon Jun 04 13:19:27 2018 -0700
committerGitHub <noreply@github.com>Mon Jun 04 13:19:27 2018 -0700
tree5a617400d4a63caa755053cf465b8995b88183ad
parent6de8340e97a4f89c47a3902f89c8541f31857f2c [diff]
parenta80086735e269d743fbf19dfce57ecfd860d9685 [diff]
Merge pull request #15607 from kpayson64/upmerge_changes

Upmerge changes
tree: 5a617400d4a63caa755053cf465b8995b88183ad
  1. .github/
  2. .vscode/
  3. bazel/
  4. cmake/
  5. doc/
  6. etc/
  7. examples/
  8. include/
  9. src/
  10. summerofcode/
  11. templates/
  12. test/
  13. third_party/
  14. tools/
  15. vsprojects/
  16. .clang-format
  17. .clang_complete
  18. .editorconfig
  19. .gitignore
  20. .gitmodules
  21. .istanbul.yml
  22. .pylintrc
  23. .pylintrc-tests
  24. .rspec
  25. .travis.yml
  26. .yardopts
  27. AUTHORS
  28. BUILD
  29. build.yaml
  30. build_config.rb
  31. CMakeLists.txt
  32. CODE-OF-CONDUCT.md
  33. composer.json
  34. config.m4
  35. config.w32
  36. CONTRIBUTING.md
  37. Gemfile
  38. gRPC-C++.podspec
  39. gRPC-Core.podspec
  40. gRPC-ProtoRPC.podspec
  41. gRPC-RxLibrary.podspec
  42. grpc.bzl
  43. grpc.def
  44. grpc.gemspec
  45. grpc.gyp
  46. gRPC.podspec
  47. INSTALL.md
  48. LICENSE
  49. Makefile
  50. MANIFEST.md
  51. NOTICE.txt
  52. OWNERS
  53. package.xml
  54. PYTHON-MANIFEST.in
  55. Rakefile
  56. README.md
  57. requirements.txt
  58. setup.cfg
  59. setup.py
  60. WORKSPACE
README.md

gRPC - An RPC library and framework

Join the chat at https://gitter.im/grpc/grpc

Copyright 2015 The gRPC Authors

Documentation

You can find more detailed documentation and examples in the doc and examples directories respectively.

Installation & Testing

See INSTALL for installation instructions for various platforms.

See tools/run_tests for more guidance on how to run various test suites (e.g. unit tests, interop tests, benchmarks)

See Performance dashboard for the performance numbers for the latest released version.

Repository Structure & Status

This repository contains source code for gRPC libraries for multiple languages written on top of shared C core library src/core.

Libraries in different languages may be in different states of development. We are seeking contributions for all of these libraries.

LanguageSource
Shared C [core library]src/core
C++src/cpp
Rubysrc/ruby
Pythonsrc/python
PHPsrc/php
C#src/csharp
Objective-Csrc/objective-c
LanguageSource repo
Javagrpc-java
Gogrpc-go
NodeJSgrpc-node
WebJSgrpc-web
Dartgrpc-dart

See MANIFEST.md for a listing of top-level items in the repository.

Overview

Remote Procedure Calls (RPCs) provide a useful abstraction for building distributed applications and services. The libraries in this repository provide a concrete implementation of the gRPC protocol, layered over HTTP/2. These libraries enable communication between clients and servers using any combination of the supported languages.

Interface

Developers using gRPC typically start with the description of an RPC service (a collection of methods), and generate client and server side interfaces which they use on the client-side and implement on the server side.

By default, gRPC uses Protocol Buffers as the Interface Definition Language (IDL) for describing both the service interface and the structure of the payload messages. It is possible to use other alternatives if desired.

Surface API

Starting from an interface definition in a .proto file, gRPC provides Protocol Compiler plugins that generate Client- and Server-side APIs. gRPC users typically call into these APIs on the Client side and implement the corresponding API on the server side.

Synchronous vs. asynchronous

Synchronous RPC calls, that block until a response arrives from the server, are the closest approximation to the abstraction of a procedure call that RPC aspires to.

On the other hand, networks are inherently asynchronous and in many scenarios, it is desirable to have the ability to start RPCs without blocking the current thread.

The gRPC programming surface in most languages comes in both synchronous and asynchronous flavors.

Streaming

gRPC supports streaming semantics, where either the client or the server (or both) send a stream of messages on a single RPC call. The most general case is Bidirectional Streaming where a single gRPC call establishes a stream where both the client and the server can send a stream of messages to each other. The streamed messages are delivered in the order they were sent.

Protocol

The gRPC protocol specifies the abstract requirements for communication between clients and servers. A concrete embedding over HTTP/2 completes the picture by fleshing out the details of each of the required operations.

Abstract gRPC protocol

A gRPC RPC comprises of a bidirectional stream of messages, initiated by the client. In the client-to-server direction, this stream begins with a mandatory Call Header, followed by optional Initial-Metadata, followed by zero or more Payload Messages. The server-to-client direction contains an optional Initial-Metadata, followed by zero or more Payload Messages terminated with a mandatory Status and optional Status-Metadata (a.k.a.,Trailing-Metadata).

Implementation over HTTP/2

The abstract protocol defined above is implemented over HTTP/2. gRPC bidirectional streams are mapped to HTTP/2 streams. The contents of Call Header and Initial Metadata are sent as HTTP/2 headers and subject to HPACK compression. Payload Messages are serialized into a byte stream of length prefixed gRPC frames which are then fragmented into HTTP/2 frames at the sender and reassembled at the receiver. Status and Trailing-Metadata are sent as HTTP/2 trailing headers (a.k.a., trailers).

Flow Control

gRPC inherits the flow control mechanisms in HTTP/2 and uses them to enable fine-grained control of the amount of memory used for buffering in-flight messages.