setup.go

package k8scrd

/*
Copyright 2022 The k8gb Contributors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Generated by GoLic, for more details see: https://github.com/AbsaOSS/golic
*/

import (
	"fmt"
	"strconv"

	"github.com/AbsaOSS/k8s_crd/service/gateway"
	"github.com/AbsaOSS/k8s_crd/service/wrr"

	"github.com/coredns/caddy"
	"github.com/coredns/coredns/core/dnsserver"
	"github.com/coredns/coredns/plugin"
	clog "github.com/coredns/coredns/plugin/pkg/log"
)

type args struct {
	annotation      string
	apex            string
	filter          string
	kubecontroller  string
	loadbalance     string
	negttl          uint32
	ttl             uint32
	zones           []string
	geoDataFilePath string
	geoDataField    string
}

const thisPlugin = "k8s_crd"
const weightRoundRobin = "weight"

var log = clog.NewWithPlugin(thisPlugin)

func init() {
	plugin.Register(thisPlugin, setup)
}

func setup(c *caddy.Controller) error {

	rawArgs, err := parse(c)
	if err != nil {
		return plugin.Error(thisPlugin, err)
	}

	k8sCRD, err := NewK8sCRD(configType(rawArgs.kubecontroller), rawArgs.filter)
	if err != nil {
		return plugin.Error(thisPlugin, err)
	}
	gwopts := gateway.NewGatewayOpts(rawArgs.annotation, rawArgs.apex, rawArgs.geoDataFilePath, rawArgs.geoDataField, rawArgs.ttl, rawArgs.negttl, rawArgs.zones)
	_ = k8sCRD.container.Register(gateway.NewGateway(gwopts))
	if rawArgs.loadbalance == weightRoundRobin {
		_ = k8sCRD.container.Register(wrr.NewWeightRoundRobin())
	}
	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
		k8sCRD.Next = next
		return k8sCRD
	})

	return nil
}

func parseTTL(opt, arg string) (uint32, error) {
	t, err := strconv.Atoi(arg)
	if err != nil {
		return uint32(t), err
	}
	if t < 0 || t > 3600 {
		return uint32(t), fmt.Errorf("%s must be in range [0, 3600]: %d", opt, t)
	}
	return uint32(t), nil
}

func parse(c *caddy.Controller) (args, error) {
	a := args{}
	for c.Next() {
		a.zones = plugin.OriginsFromArgsOrServerBlock(c.RemainingArgs(), c.ServerBlockKeys)

		for c.NextBlock() {
			key := c.Val()
			args := c.RemainingArgs()
			if len(args) == 0 {
				return a, c.ArgErr()
			}
			switch key {
			case "filter":
				log.Infof("Filter: %+v", args)
				a.filter = args[0]
			case "annotation":
				log.Infof("annotation: %+v", args)
				a.annotation = args[0]
			case "ttl":
				ttl, err := parseTTL(c.Val(), args[0])
				if err != nil {
					a.ttl = ttl
				}
			case "negttl":
				log.Infof("negTTL: %+v", args[0])
				negttl, err := parseTTL(c.Val(), args[0])
				if err == nil {
					a.negttl = negttl
				}
			case "apex":
				a.apex = args[0]
			case "kubecontroller":
				log.Infof("kubecontroller: %+v", args)
				a.kubecontroller = args[0]
			case "loadbalance":
				log.Infof("loadbalance: %+v", args)
				a.loadbalance = args[0]
			case "geodatafilepath":
				log.Infof("geodatafilepath: %+v", args)
				a.geoDataFilePath = args[0]
			case "geodatafield":
				log.Infof("geodatafield: %+v", args)
				a.geoDataField = args[0]
			default:
				return a, c.Errf("Unknown property '%s'", c.Val())
			}
		}
	}
	return a, nil
}