I found the official docs on using Google Protocol Buffers from Go a bit confusing, and couldn’t find any other clearly written blog posts on the subject, so I figured I’d write my own.
This will walk you through the following:
- Install golang/protobuf and required dependencies
- Generating Go wrappers for a test protocol buffer definition
- Using those Go wrappers to marshal and unmarshal an object
Install protoc binary
Since the protocol buffer compiler
protoc is required later, we must install it.
If you want to use an older version (v2.5), simply do:
Otherwise if you want the latest version (v2.6):
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Install Go Protobuf library
This assumes you have Go 1.2+ or later already installed, and your
$GOPATH variable set.
In order to generate Go wrappers, we need to install the following:
Download a test .proto file
In order to generate wrappers, we need a
.proto file with object definitions.
This one is a slightly modified version of the one from the official docs.
Generate Go wrappers
You should end up with a new file generated:
Marshalling and unmarshalling an object
Open a new file
main.go in emacs or your favorite editor, and paste the following:
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- Lines 11-14: Create a new object suitable for protobuf marshalling and populate it’s fields. Note that using
proto.Int32(..)isn’t strictly required, they are just convencience wrappers to get string / int pointers.
- Line 18: Marshal to a byte array.
- Line 22: Create a new empty object.
- Line 23: Unmarshal previously marshalled byte array into new object
- Line 28: Verify that the “label” field made the marshal/unmarshall round trip safely
Run it via:
and you should see the output:
Congratulations! You are now using protocol buffers from Go.