modelgen.md

modelgen

modelgen generates Go model types from an OVSDB schema file, so you don't need to write them by hand. It produces one struct per table and a FullDatabaseModel() convenience function.

Installation

go install github.com/ovn-kubernetes/libovsdb/cmd/modelgen

Usage

modelgen [flags] OVS_SCHEMA

Flags:
  -d        Dry run (print output, don't write files)
  -o string Directory where generated files are stored (default ".")
  -p string Package name (default "ovsmodel")

Example

1. Get the schema from a running OVSDB server:

ovsdb-client get-schema "tcp:localhost:6641" > mypackage/ovs-nb.ovsschema

2. Add a go:generate directive:

// mypackage/gen.go
package mypackage

//go:generate modelgen -p mypackage -o . ovs-nb.ovsschema

3. Run code generation:

go generate ./...

This writes one .go file per table plus a FullDatabaseModel() function.

Using the Generated Code

import (
    "context"
    "fmt"

    "github.com/ovn-kubernetes/libovsdb/client"
    generated "example.com/example/mypackage"
)

func main() {
    dbModel, err := generated.FullDatabaseModel()
    if err != nil { ... }

    ovs, err := client.NewOVSDBClient(dbModel, client.WithEndpoint("tcp:localhost:6641"))
    if err != nil { ... }

    err = ovs.Connect(context.Background())
    err = ovs.MonitorAll(context.Background())

    lr := &generated.LogicalRouter{Name: "myRouter"}
    err = ovs.Get(context.Background(), lr)
    fmt.Printf("Router %s has %d ports\n", lr.Name, len(lr.Ports))
}