--- /dev/null
+# Go support for Protocol Buffers
+
+[](https://travis-ci.org/golang/protobuf)
+[](https://godoc.org/github.com/golang/protobuf)
+
+Google's data interchange format.
+Copyright 2010 The Go Authors.
+https://github.com/golang/protobuf
+
+This package and the code it generates requires at least Go 1.4.
+
+This software implements Go bindings for protocol buffers. For
+information about protocol buffers themselves, see
+ https://developers.google.com/protocol-buffers/
+
+## Installation ##
+
+To use this software, you must:
+- Install the standard C++ implementation of protocol buffers from
+ https://developers.google.com/protocol-buffers/
+- Of course, install the Go compiler and tools from
+ https://golang.org/
+ See
+ https://golang.org/doc/install
+ for details or, if you are using gccgo, follow the instructions at
+ https://golang.org/doc/install/gccgo
+- Grab the code from the repository and install the proto package.
+ The simplest way is to run `go get -u github.com/golang/protobuf/protoc-gen-go`.
+ The compiler plugin, protoc-gen-go, will be installed in $GOBIN,
+ defaulting to $GOPATH/bin. It must be in your $PATH for the protocol
+ compiler, protoc, to find it.
+
+This software has two parts: a 'protocol compiler plugin' that
+generates Go source files that, once compiled, can access and manage
+protocol buffers; and a library that implements run-time support for
+encoding (marshaling), decoding (unmarshaling), and accessing protocol
+buffers.
+
+There is support for gRPC in Go using protocol buffers.
+See the note at the bottom of this file for details.
+
+There are no insertion points in the plugin.
+
+
+## Using protocol buffers with Go ##
+
+Once the software is installed, there are two steps to using it.
+First you must compile the protocol buffer definitions and then import
+them, with the support library, into your program.
+
+To compile the protocol buffer definition, run protoc with the --go_out
+parameter set to the directory you want to output the Go code to.
+
+ protoc --go_out=. *.proto
+
+The generated files will be suffixed .pb.go. See the Test code below
+for an example using such a file.
+
+
+The package comment for the proto library contains text describing
+the interface provided in Go for protocol buffers. Here is an edited
+version.
+
+==========
+
+The proto package converts data structures to and from the
+wire format of protocol buffers. It works in concert with the
+Go source code generated for .proto files by the protocol compiler.
+
+A summary of the properties of the protocol buffer interface
+for a protocol buffer variable v:
+
+ - Names are turned from camel_case to CamelCase for export.
+ - There are no methods on v to set fields; just treat
+ them as structure fields.
+ - There are getters that return a field's value if set,
+ and return the field's default value if unset.
+ The getters work even if the receiver is a nil message.
+ - The zero value for a struct is its correct initialization state.
+ All desired fields must be set before marshaling.
+ - A Reset() method will restore a protobuf struct to its zero state.
+ - Non-repeated fields are pointers to the values; nil means unset.
+ That is, optional or required field int32 f becomes F *int32.
+ - Repeated fields are slices.
+ - Helper functions are available to aid the setting of fields.
+ Helpers for getting values are superseded by the
+ GetFoo methods and their use is deprecated.
+ msg.Foo = proto.String("hello") // set field
+ - Constants are defined to hold the default values of all fields that
+ have them. They have the form Default_StructName_FieldName.
+ Because the getter methods handle defaulted values,
+ direct use of these constants should be rare.
+ - Enums are given type names and maps from names to values.
+ Enum values are prefixed with the enum's type name. Enum types have
+ a String method, and a Enum method to assist in message construction.
+ - Nested groups and enums have type names prefixed with the name of
+ the surrounding message type.
+ - Extensions are given descriptor names that start with E_,
+ followed by an underscore-delimited list of the nested messages
+ that contain it (if any) followed by the CamelCased name of the
+ extension field itself. HasExtension, ClearExtension, GetExtension
+ and SetExtension are functions for manipulating extensions.
+ - Oneof field sets are given a single field in their message,
+ with distinguished wrapper types for each possible field value.
+ - Marshal and Unmarshal are functions to encode and decode the wire format.
+
+When the .proto file specifies `syntax="proto3"`, there are some differences:
+
+ - Non-repeated fields of non-message type are values instead of pointers.
+ - Enum types do not get an Enum method.
+
+Consider file test.proto, containing
+
+```proto
+ syntax = "proto2";
+ package example;
+
+ enum FOO { X = 17; };
+
+ message Test {
+ required string label = 1;
+ optional int32 type = 2 [default=77];
+ repeated int64 reps = 3;
+ optional group OptionalGroup = 4 {
+ required string RequiredField = 5;
+ }
+ }
+```
+
+To create and play with a Test object from the example package,
+
+```go
+ package main
+
+ import (
+ "log"
+
+ "github.com/golang/protobuf/proto"
+ "path/to/example"
+ )
+
+ func main() {
+ test := &example.Test {
+ Label: proto.String("hello"),
+ Type: proto.Int32(17),
+ Reps: []int64{1, 2, 3},
+ Optionalgroup: &example.Test_OptionalGroup {
+ RequiredField: proto.String("good bye"),
+ },
+ }
+ data, err := proto.Marshal(test)
+ if err != nil {
+ log.Fatal("marshaling error: ", err)
+ }
+ newTest := &example.Test{}
+ err = proto.Unmarshal(data, newTest)
+ if err != nil {
+ log.Fatal("unmarshaling error: ", err)
+ }
+ // Now test and newTest contain the same data.
+ if test.GetLabel() != newTest.GetLabel() {
+ log.Fatalf("data mismatch %q != %q", test.GetLabel(), newTest.GetLabel())
+ }
+ // etc.
+ }
+```
+
+## Parameters ##
+
+To pass extra parameters to the plugin, use a comma-separated
+parameter list separated from the output directory by a colon:
+
+
+ protoc --go_out=plugins=grpc,import_path=mypackage:. *.proto
+
+
+- `import_prefix=xxx` - a prefix that is added onto the beginning of
+ all imports. Useful for things like generating protos in a
+ subdirectory, or regenerating vendored protobufs in-place.
+- `import_path=foo/bar` - used as the package if no input files
+ declare `go_package`. If it contains slashes, everything up to the
+ rightmost slash is ignored.
+- `plugins=plugin1+plugin2` - specifies the list of sub-plugins to
+ load. The only plugin in this repo is `grpc`.
+- `Mfoo/bar.proto=quux/shme` - declares that foo/bar.proto is
+ associated with Go package quux/shme. This is subject to the
+ import_prefix parameter.
+
+## gRPC Support ##
+
+If a proto file specifies RPC services, protoc-gen-go can be instructed to
+generate code compatible with gRPC (http://www.grpc.io/). To do this, pass
+the `plugins` parameter to protoc-gen-go; the usual way is to insert it into
+the --go_out argument to protoc:
+
+ protoc --go_out=plugins=grpc:. *.proto
+
+## Compatibility ##
+
+The library and the generated code are expected to be stable over time.
+However, we reserve the right to make breaking changes without notice for the
+following reasons:
+
+- Security. A security issue in the specification or implementation may come to
+ light whose resolution requires breaking compatibility. We reserve the right
+ to address such security issues.
+- Unspecified behavior. There are some aspects of the Protocol Buffers
+ specification that are undefined. Programs that depend on such unspecified
+ behavior may break in future releases.
+- Specification errors or changes. If it becomes necessary to address an
+ inconsistency, incompleteness, or change in the Protocol Buffers
+ specification, resolving the issue could affect the meaning or legality of
+ existing programs. We reserve the right to address such issues, including
+ updating the implementations.
+- Bugs. If the library has a bug that violates the specification, a program
+ that depends on the buggy behavior may break if the bug is fixed. We reserve
+ the right to fix such bugs.
+- Adding methods or fields to generated structs. These may conflict with field
+ names that already exist in a schema, causing applications to break. When the
+ code generator encounters a field in the schema that would collide with a
+ generated field or method name, the code generator will append an underscore
+ to the generated field or method name.
+- Adding, removing, or changing methods or fields in generated structs that
+ start with `XXX`. These parts of the generated code are exported out of
+ necessity, but should not be considered part of the public API.
+- Adding, removing, or changing unexported symbols in generated code.
+
+Any breaking changes outside of these will be announced 6 months in advance to
+protobuf@googlegroups.com.
+
+You should, whenever possible, use generated code created by the `protoc-gen-go`
+tool built at the same commit as the `proto` package. The `proto` package
+declares package-level constants in the form `ProtoPackageIsVersionX`.
+Application code and generated code may depend on one of these constants to
+ensure that compilation will fail if the available version of the proto library
+is too old. Whenever we make a change to the generated code that requires newer
+library support, in the same commit we will increment the version number of the
+generated code and declare a new package-level constant whose name incorporates
+the latest version number. Removing a compatibility constant is considered a
+breaking change and would be subject to the announcement policy stated above.
+
+The `protoc-gen-go/generator` package exposes a plugin interface,
+which is used by the gRPC code generation. This interface is not
+supported and is subject to incompatible changes without notice.
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