http/main.go

// Copyright 2020 Google LLC
//
// 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.

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"text/template"

	cbpb "cloud.google.com/go/cloudbuild/apiv1/v2/cloudbuildpb"
	"github.com/GoogleCloudPlatform/cloud-build-notifiers/lib/notifiers"
	log "github.com/golang/glog"
)

const (
	urlSecretName = "urlRef"
)

func main() {
	if err := notifiers.Main(new(httpNotifier)); err != nil {
		log.Fatalf("fatal error: %v", err)
	}
}

type httpNotifier struct {
	filter   notifiers.EventFilter
	tmpl     *template.Template
	url      string
	br       notifiers.BindingResolver
	tmplView *notifiers.TemplateView
}

func (h *httpNotifier) SetUp(ctx context.Context, cfg *notifiers.Config, httpTemplate string, sg notifiers.SecretGetter, br notifiers.BindingResolver) error {
	prd, err := notifiers.MakeCELPredicate(cfg.Spec.Notification.Filter)
	if err != nil {
		return fmt.Errorf("failed to create CELPredicate: %w", err)
	}
	h.filter = prd
	h.br = br

	if url, ok := cfg.Spec.Notification.Delivery["url"].(string); ok {
		h.url = url
	} else {
		uRef, err := notifiers.GetSecretRef(cfg.Spec.Notification.Delivery, urlSecretName)
		if err != nil {
			return fmt.Errorf("failed to get Secret ref from delivery config (%v) field %q: %w", cfg.Spec.Notification.Delivery, urlSecretName, err)
		}
		uResource, err := notifiers.FindSecretResourceName(cfg.Spec.Secrets, uRef)
		if err != nil {
			return fmt.Errorf("failed to find Secret for ref %q: %w", uRef, err)
		}
		url, err := sg.GetSecret(ctx, uResource)
		if err != nil {
			return fmt.Errorf("failed to get token secret: %w", err)
		}
		h.url = url
	}

	tmpl, err := template.New("http_template").Parse(httpTemplate)
	if err != nil {
		return fmt.Errorf("failed to parse template: %v", err)
	}
	h.tmpl = tmpl

	return nil
}

func (h *httpNotifier) SendNotification(ctx context.Context, build *cbpb.Build) error {
	if !h.filter.Apply(ctx, build) {
		log.V(2).Infof("not sending HTTP request for event (build id = %s, status = %v)", build.Id, build.Status)
		return nil
	}

	log.Infof("sending HTTP request for event (build id = %s, status = %s)", build.Id, build.Status)

	bindings, err := h.br.Resolve(ctx, nil, build)
	if err != nil {
		return fmt.Errorf("failed to resolve bindings: %w", err)
	}
	h.tmplView = &notifiers.TemplateView{
		Build:  &notifiers.BuildView{Build: build},
		Params: bindings,
	}

	logURL, err := notifiers.AddUTMParams(build.LogUrl, notifiers.HTTPMedium)
	if err != nil {
		return fmt.Errorf("failed to add UTM params: %w", err)
	}
	build.LogUrl = logURL

	payload := new(bytes.Buffer)
	var buf bytes.Buffer
	if err := h.tmpl.Execute(&buf, h.tmplView); err != nil {
		return err
	}
	err = json.NewEncoder(payload).Encode(buf)
	if err != nil {
		return fmt.Errorf("failed to encode payload: %w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, h.url, strings.NewReader(buf.String()))
	if err != nil {
		return fmt.Errorf("failed to create a new HTTP request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("User-Agent", "GCB-Notifier/0.1 (http)")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to make HTTP request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		log.Warningf("got a non-OK response status %q (%d) from %q", resp.Status, resp.StatusCode, h.url)
	}

	log.V(2).Infoln("send HTTP request successfully")
	return nil
}