3 The GoVPP projects provides the API for communication with VPP from Go.
5 It consists of the following packages:
6 - [adapter](adapter/): adapter between GoVPP core and the VPP binary/stats API
7 - [api](api/): API for communication with GoVPP core
8 - [cmd/binapi-generator](cmd/binapi-generator/): generator for the VPP binary API definitions in JSON format to Go code
9 - [codec](codec/): handles encoding/decoding of generated messages into binary form
10 - [core](core/): essential functionality of the GoVPP
11 - [examples](examples/): examples that use the GoVPP API in real use-cases of VPP management application
12 - [extras](extras/): contains Go implementation for libmemif library
13 - [govpp](govpp.go): provides the entry point to GoVPP functionality
15 The design with separated GoVPP [API package](api/) and the GoVPP [core package](core/) enables
16 plugin-based infrastructure, where one entity acts as a master responsible for talking with VPP and multiple
17 entities act as clients that are using the master for the communication with VPP.
18 The clients can be built into standalone shared libraries without the need
19 of linking the GoVPP core and all its dependencies into them.
26 | App | +--------------+
27 | | +------+ GoVPP API |
28 | | | +--------------+
29 +--------------+ GoVPP |
30 | | channels | +--------------+
31 | GoVPP core +------------+ | |
33 +------+-------+ | | |
35 | +------+ GoVPP API |
36 | binary API +--------------+
47 #### Generate binapi (Go bindings)
49 Generating Go bindings for VPP binary API from the JSON files located in the
50 `/usr/share/vpp/api/` directory into the Go packages that will be created
51 inside of the `binapi` directory:
54 binapi-generator --input-dir=/usr/share/vpp/api/ --output-dir=binapi
59 Here is a usage sample of the generated binapi messages:
64 conn, _ := govpp.Connect()
65 defer conn.Disconnect()
68 ch, _ := conn.NewAPIChannel()
72 req := &vpe.ShowVersion{}
73 reply := &vpe.ShowVersionReply{}
76 err := ch.SendRequest(req).ReceiveReply(reply)
80 The example above uses GoVPP API to communicate over underlying go channels,
81 see [example client](examples/simple-client/simple_client.go)
82 for more examples, including the example on how to use the Go channels directly.
86 ### Using pure Go adapters (recommended)
88 GoVPP now supports pure Go implementation for VPP binary API. This does
89 not depend on CGo or any VPP library and can be easily compiled.
91 There are two packages providing pure Go implementations in GoVPP:
92 - [`socketclient`](adapter/socketclient) - for VPP binary API (via unix socket)
93 - [`statsclient`](adapter/statsclient) - for VPP stats API (via shared memory)
95 ### Using vppapiclient library wrapper (requires CGo)
97 GoVPP also provides vppapiclient package which actually uses
98 `vppapiclient.so` library from VPP codebase to communicate with VPP API.
99 To build GoVPP, `vpp-dev` package must be installed,
100 either [from packages][from-packages] or [from sources][from-sources].
102 To build & install `vpp-dev` from sources:
105 git clone https://gerrit.fd.io/r/vpp
110 sudo dpkg -i vpp*.deb
113 To build & install GoVPP:
116 go get -u git.fd.io/govpp.git
117 cd $GOPATH/src/git.fd.io/govpp.git
122 ## Generating Go bindings with binapi-generator
124 Once you have `binapi-generator` installed, you can use it to generate Go bindings for VPP binary API
125 using VPP APIs in JSON format. The JSON input can be specified as a single file (`input-file` argument), or
126 as a directory that will be scanned for all `.json` files (`input-dir`). The generated Go bindings will
127 be placed into `output-dir` (by default current working directory), where each Go package will be placed into
128 a separated directory, e.g.:
131 binapi-generator --input-file=acl.api.json --output-dir=binapi
132 binapi-generator --input-dir=/usr/share/vpp/api/core --output-dir=binapi
135 In Go, [go generate](https://blog.golang.org/generate) tool can be leveraged to ease the code generation
136 process. It allows to specify generator instructions in any one of the regular (non-generated) `.go` files
137 that are dependent on generated code using special comments, e.g. the one from
138 [example client](examples/simple-client/simple_client.go):
141 //go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
144 [from-packages]: https://wiki.fd.io/view/VPP/Installing_VPP_binaries_from_packages
145 [from-sources]: https://wiki.fd.io/view/VPP/Build,_install,_and_test_images#Build_A_VPP_Package