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diff --git a/docs/GENERATOR.md b/docs/GENERATOR.md new file mode 100644 index 0000000..d7832ac --- /dev/null +++ b/docs/GENERATOR.md @@ -0,0 +1,68 @@ +# Binapi Generator + +## Install the binary API generator + +```sh +# Install binapi generator +make install-generator +``` + +> NOTE: This installs `binapi-generator` to `$GOPATH/bin` directory, ensure +> it is in your `$PATH` before running the command. + +## 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/`. + +```sh +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.: + +```sh +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](https://blog.golang.org/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 +//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 +<something>.ba.go. Suggest: + +``` +find git.fd.io/govpp/binapi -name "*.ba.go" | xargs grep -n GoTypeName +``` + +Look at the indicated <something>.ba.go file, deduce the package name +and import it. See the example above. |