README.md

   1 # GoVPP
   2
   3 This set of packages provide the API for communication with VPP from Go.
   4
   5 It consists of the following packages:
   6 - [adapter](adapter/): adapter between GoVPP core and the VPP
   7 - [api](api/api.go): API for communication with GoVPP core
   8 - [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/): main 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
  14
  15 The design with separated GoVPP [API package](api/api.go) 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.
  20
  21 ```
  22                                        +--------------+
  23     +--------------+                   |              |
  24     |              |                   |  App plugin  |
  25     |              |                   |              |
  26     |     App      |                   +--------------+
  27     |              |            +------+  GoVPP API   |
  28     |              |            |      +--------------+
  29     +--------------+     Go     |
  30     |              |  channels  |      +--------------+
  31     |  GoVPP core  +------------+      |              |
  32     |              |            |      |  App plugin  |
  33     +------+-------+            |      |              |
  34            |                    |      +--------------+
  35 binary API |                    +------+  GoVPP API   |
  36  (shmem)   |                           +--------------+
  37            |
  38     +------+-------+
  39     |              |
  40     |  VPP process |
  41     |              |
  42     +--------------+
  43 ```
  44
  45 ## Quick Start
  46
  47 #### Code Generator
  48
  49 Generating Go bindings from the JSON files located in the `/usr/share/vpp/api/` directory
  50 into the Go packages that will be created inside of the `bin_api` directory:
  51 ```
  52 binapi-generator --input-dir=/usr/share/vpp/api/ --output-dir=bin_api
  53 ```
  54
  55 #### Example Usage
  56
  57 Usage of the generated bindings:
  58
  59 ```go
  60 func main() {
  61         conn, _ := govpp.Connect()
  62         defer conn.Disconnect()
  63
  64         ch, _ := conn.NewAPIChannel()
  65         defer ch.Close()
  66
  67         req := &acl.ACLAddReplace{
  68                 ACLIndex: ^uint32(0),
  69                 Tag:      []byte("access list 1"),
  70                 R: []acl.ACLRule{
  71                         {
  72                                 IsPermit:       1,
  73                                 SrcIPAddr:      net.ParseIP("10.0.0.0").To4(),
  74                                 SrcIPPrefixLen: 8,
  75                                 DstIPAddr:      net.ParseIP("192.168.1.0").To4(),
  76                                 DstIPPrefixLen: 24,
  77                                 Proto:          6,
  78                         },
  79                         {
  80                                 IsPermit:       1,
  81                                 SrcIPAddr:      net.ParseIP("8.8.8.8").To4(),
  82                                 SrcIPPrefixLen: 32,
  83                                 DstIPAddr:      net.ParseIP("172.16.0.0").To4(),
  84                                 DstIPPrefixLen: 16,
  85                                 Proto:          6,
  86                         },
  87                 },
  88         }
  89         reply := &acl.ACLAddReplaceReply{}
  90
  91         err := ch.SendRequest(req).ReceiveReply(reply)
  92 }
  93 ```
  94
  95 The example above uses simple wrapper API over underlying go channels, see [example client](examples/cmd/simple-client/simple_client.go)
  96 for more examples, including the example on how to use the Go channels directly.
  97
  98 ## Build & Installation Procedure
  99
 100 Govpp uses `vppapiclient` library from VPP codebase to communicate with VPP. To build GoVPP, vpp-dev package must be installed,
 101 either [from packages](https://wiki.fd.io/view/VPP/Installing_VPP_binaries_from_packages) or
 102 [from sources](https://wiki.fd.io/view/VPP/Build,_install,_and_test_images#Build_A_VPP_Package).
 103
 104 To build & install `vpp-dev` from sources:
 105
 106 ```
 107 git clone https://gerrit.fd.io/r/vpp
 108 cd vpp
 109 make install-dep
 110 make bootstrap
 111 make pkg-deb
 112 cd build-root
 113 sudo dpkg -i vpp*.deb
 114 ```
 115
 116 To build & install all GoVPP binaries into your `$GOPATH`:
 117
 118 ```
 119 go get git.fd.io/govpp.git
 120 cd $GOPATH/src/git.fd.io/govpp.git
 121 make
 122 make install
 123 ```
 124
 125 ## Building Go bindings from VPP binary APIs
 126
 127 Once you have `binapi-generator` installed in your `$GOPATH`, you can use it to generate Go bindings from
 128 VPP APis in JSON format. The JSON input can be specified as a single file (`input-file` argument), or
 129 as a directory that will be scanned for all `.json` files (`input-dir`). The generated Go bindings will
 130 be placed into `output-dir` (by default current working directory), where each Go package will be placed into
 131 a separated directory, e.g.:
 132
 133 ```
 134 binapi-generator --input-file=examples/bin_api/acl.api.json --output-dir=examples/bin_api
 135 binapi-generator --input-dir=examples/bin_api --output-dir=examples/bin_api
 136 ```
 137
 138 In Go, [go generate](https://blog.golang.org/generate) tool can be leveraged to ease the code generation
 139 process. It allows to specify generator instructions in any one of the regular (non-generated) `.go` files
 140 that are dependent on generated code using special comments, e.g. the one from
 141 [example client](examples/cmd/simple-client/simple_client.go):
 142
 143 ```go
 144 //go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
 145 ```