cert-manager-webhook-example/main.go

package main

import (
	"encoding/json"
	"fmt"
	"github.com/jetstack/cert-manager/pkg/issuer/acme/dns/util"
	"io/ioutil"
	"net/http"
	"os"
	"strconv"

	extapi "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
	//"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"

	"github.com/jetstack/cert-manager/pkg/acme/webhook/apis/acme/v1alpha1"
	"github.com/jetstack/cert-manager/pkg/acme/webhook/cmd"
)

var GroupName = os.Getenv("GROUP_NAME")

func main() {
	if GroupName == "" {
		panic("GROUP_NAME must be specified")
	}

	// This will register our custom DNS provider with the webhook serving
	// library, making it available as an API under the provided GroupName.
	// You can register multiple DNS provider implementations with a single
	// webhook, where the Name() method will be used to disambiguate between
	// the different implementations.
	cmd.RunWebhookServer(GroupName,
		&bluecatDNSProviderSolver{},
	)
}

// bluecatDNSProviderSolver implements the provider-specific logic needed to
// 'present' an ACME challenge TXT record for your own DNS provider.
// To do so, it must implement the `github.com/jetstack/cert-manager/pkg/acme/webhook.Solver`
// interface.
type bluecatDNSProviderSolver struct {
	// If a Kubernetes 'clientset' is needed, you must:
	// 1. uncomment the additional `client` field in this structure below
	// 2. uncomment the "k8s.io/client-go/kubernetes" import at the top of the file
	// 3. uncomment the relevant code in the Initialize method below
	// 4. ensure your webhook's service account has the required RBAC role
	//    assigned to it for interacting with the Kubernetes APIs you need.
	//client kubernetes.Clientset
}

// bluecatDNSProviderConfig is a structure that is used to decode into when
// solving a DNS01 challenge.
// This information is provided by cert-manager, and may be a reference to
// additional configuration that's needed to solve the challenge for this
// particular certificate or issuer.
// This typically includes references to Secret resources containing DNS
// provider credentials, in cases where a 'multi-tenant' DNS solver is being
// created.
// If you do *not* require per-issuer or per-certificate configuration to be
// provided to your webhook, you can skip decoding altogether in favour of
// using CLI flags or similar to provide configuration.
// You should not include sensitive information here. If credentials need to
// be used by your provider here, you should reference a Kubernetes Secret
// resource and fetch these credentials using a Kubernetes clientset.
type bluecatDNSProviderConfig struct {
	Username   string `json:"username"`
	Password   string `json:"password"`
	ServerURL  string `json:"server_url"`
	ConfigName string `json:"config_name"`
	DNSView    string `json:"dns_view"`
}

// Name is used as the name for this DNS solver when referencing it on the ACME
// Issuer resource.
// This should be unique **within the group name**, i.e. you can have two
// solvers configured with the same Name() **so long as they do not co-exist
// within a single webhook deployment**.
// For example, `cloudflare` may be used as the name of a solver.
func (c *bluecatDNSProviderSolver) Name() string {
	return "bluecat"
}

// Present is responsible for actually presenting the DNS record with the
// DNS provider.
// This method should tolerate being called multiple times with the same value.
// cert-manager itself will later perform a self check to ensure that the
// solver has correctly configured the DNS provider.
func (c *bluecatDNSProviderSolver) Present(ch *v1alpha1.ChallengeRequest) error {
	cfg, err := loadConfig(ch.Config)
	if err != nil {
		return err
	}

	source := util.UnFqdn(ch.ResolvedFQDN)
	target := ch.Key

	err = bluecatLogin(cfg.ServerURL, cfg.Username, cfg.Password, cfg.ConfigName)
	if err != nil {
		return err
	}

	viewID, err := bluecatLookupViewID(cfg.DNSView)
	if err != nil {
		return err
	}

	parentZoneID, name, err := bluecatLookupParentZoneID(viewID, source)
	if err != nil {
		return err
	}

	queryArgs := map[string]string{
		"parentId": strconv.FormatUint(uint64(parentZoneID), 10),
	}

	body := bluecatEntity{
		Name:       name,
		Type:       "TXTRecord",
		Properties: fmt.Sprintf("ttl=300|absoluteName=%s|txt=%s", source, target),
	}

	resp, err := bluecatSendRequest(http.MethodPost, "addEntity", body, queryArgs)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	addTxtBytes, _ := ioutil.ReadAll(resp.Body)
	addTxtResp := string(addTxtBytes)
	// addEntity responds only with body text containing the ID of the created record
	_, err = strconv.ParseUint(addTxtResp, 10, 64)
	if err != nil {
		return fmt.Errorf("bluecat: addEntity request failed: %s", addTxtResp)
	}

	err = bluecatDeploy(parentZoneID)
	if err != nil {
		return err
	}

	err = bluecatLogout()
	if err != nil {
		return err
	}

	return nil
}

// CleanUp should delete the relevant TXT record from the DNS provider console.
// If multiple TXT records exist with the same record name (e.g.
// _acme-challenge.example.com) then **only** the record with the same `key`
// value provided on the ChallengeRequest should be cleaned up.
// This is in order to facilitate multiple DNS validations for the same domain
// concurrently.
func (c *bluecatDNSProviderSolver) CleanUp(ch *v1alpha1.ChallengeRequest) error {
	cfg, err := loadConfig(ch.Config)
	if err != nil {
		return err
	}

	source := util.UnFqdn(ch.ResolvedFQDN)

	err = bluecatLogin(cfg.ServerURL, cfg.Username, cfg.Password, cfg.ConfigName)
	if err != nil {
		return err
	}

	viewID, err := bluecatLookupViewID(cfg.ConfigName)
	if err != nil {
		return err
	}

	parentID, name, err := bluecatLookupParentZoneID(viewID, source)
	if err != nil {
		return err
	}

	queryArgs := map[string]string{
		"parentId": strconv.FormatUint(uint64(parentID), 10),
		"name":     name,
		"type":     "TXTRecord",
	}

	resp, err := bluecatSendRequest(http.MethodGet, "getEntityByName", nil, queryArgs)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var txtRec entityResponse
	err = json.NewDecoder(resp.Body).Decode(&txtRec)
	if err != nil {
		return fmt.Errorf("bluecat: %w", err)
	}
	queryArgs = map[string]string{
		"objectId": strconv.FormatUint(uint64(txtRec.ID), 10),
	}

	resp, err = bluecatSendRequest(http.MethodDelete, http.MethodDelete, nil, queryArgs)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	err = bluecatDeploy(parentID)
	if err != nil {
		return err
	}

	err = bluecatLogout()
	if err != nil {
		return err
	}

	return nil
}

// Initialize will be called when the webhook first starts.
// This method can be used to instantiate the webhook, i.e. initialising
// connections or warming up caches.
// Typically, the kubeClientConfig parameter is used to build a Kubernetes
// client that can be used to fetch resources from the Kubernetes API, e.g.
// Secret resources containing credentials used to authenticate with DNS
// provider accounts.
// The stopCh can be used to handle early termination of the webhook, in cases
// where a SIGTERM or similar signal is sent to the webhook process.
func (c *bluecatDNSProviderSolver) Initialize(kubeClientConfig *rest.Config, stopCh <-chan struct{}) error {
	///// UNCOMMENT THE BELOW CODE TO MAKE A KUBERNETES CLIENTSET AVAILABLE TO
	///// YOUR CUSTOM DNS PROVIDER

	//cl, err := kubernetes.NewForConfig(kubeClientConfig)
	//if err != nil {
	//	return err
	//}
	//
	//c.client = cl

	///// END OF CODE TO MAKE KUBERNETES CLIENTSET AVAILABLE
	return nil
}

// loadConfig is a small helper function that decodes JSON configuration into
// the typed config struct.
func loadConfig(cfgJSON *extapi.JSON) (bluecatDNSProviderConfig, error) {
	cfg := bluecatDNSProviderConfig{}
	// handle the 'base case' where no configuration has been provided
	if cfgJSON == nil {
		return cfg, nil
	}
	if err := json.Unmarshal(cfgJSON.Raw, &cfg); err != nil {
		return cfg, fmt.Errorf("error decoding solver config: %v", err)
	}

	return cfg, nil
}