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Generator

This document contains information about GoVPP generator which is used for generating Go bindings for VPP binary API.

Installation

Prerequisites

Install via Go toolchain

# Latest version (most recent tag)
go install go.fd.io/govpp/cmd/binapi-generator@latest

# Development version (master branch)
go install go.fd.io/govpp/cmd/binapi-generator@master

Install from source

# Clone repository
git clone https://github.com/FDio/govpp
cd govpp

# Install binapi-generator
make install-generator

Generating binapi

Install vpp binary artifacts

Build locally, or download from packagecloud. Read more: https://fd.io/docs/vpp/master/gettingstarted/installing

Generate binapi (Go bindings)

Generating Go bindings for VPP binary API from the JSON files installed with the vpp binary artifacts - located in /usr/share/vpp/api/.

make generate-binapi
INFO[0000] found 110 files in API dir "/usr/share/vpp/api"
INFO[0000] Generating 203 files

The generated files will be generated under binapi directory.

Generate VPP binary API code (Go bindings)

Once you have binapi-generator installed, you can use it to generate Go bindings for VPP binary API using VPP APIs in JSON format. The JSON input can be specified as a single file (input-file argument), or as a directory that will be scanned for all .json files (input-dir). The generated Go bindings will be placed into output-dir (by default current working directory), where each Go package will be placed into a separated directory, e.g.:

binapi-generator --input-file=acl.api.json --output-dir=binapi
binapi-generator --input-dir=/usr/share/vpp/api/core --output-dir=binapi

In Go, go generate tool can be leveraged to ease the code generation process. It allows specifying generator instructions in any one of the regular (non-generated) .go files that are dependent on generated code using special comments:

//go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api

Tracking down generated go code for a specific binary API

Golang uses capitalization to indicate exported names, so you'll have to divide through by binapi-generator transformations. Example:

define create_loopback  -> type CreateLoopback struct ...
   vpp binapi definition      govpp exported type definition

The droids you're looking for will be in a file named .ba.go. Suggest:

find git.fd.io/govpp/binapi -name "*.ba.go" | xargs grep -n GoTypeName

Look at the indicated .ba.go file, deduce the package name and import it. See the example above.