merge(feat/besadii): Integrate besadii at //ops/besadii r/569

This tool supersedes the previous //ops/sync-gcsr, which no longer
exists.

Besadii runs as a git post-receive hook and triggers builds for the
depot on sourcehut. Builds are only triggered for branches, not for
tags.

The sourcehut token is read from /etc/secrets where it has been
manually placed on camden.

Besadii was a hutt kajidic, and also part of the Hutt Clan.

1 files changed, 197 insertions, 0 deletions

diff --git a/ops/besadii/main.go b/ops/besadii/main.go
new file mode 100644
index 0000000000..460eddf265
--- /dev/null
+++ b/ops/besadii/main.go
@@ -0,0 +1,197 @@
+// Copyright 2019 Google LLC.
+// SPDX-License-Identifier: Apache-2.0
+//
+// besadii is a small CLI tool that triggers depot builds on
+// builds.sr.ht
+//
+// It is designed to run as a post-update git hook on the server
+// hosting the depot.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log/syslog"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+var gitBin = "git"
+
+// Represents an updated reference as passed to besadii by git
+//
+// https://git-scm.com/docs/githooks#pre-receive
+type refUpdate struct {
+	name string
+	old  string
+	new  string
+}
+
+// Represents a builds.sr.ht build object as described on
+// https://man.sr.ht/builds.sr.ht/api.md
+type Build struct {
+	Manifest string   `json:"manifest"`
+	Note     string   `json:"note"`
+	Tags     []string `json:"tags"`
+}
+
+// Represents a build trigger object as described on <the docs for
+// this are currently down>
+type Trigger struct {
+	Action    string `json:"action"`
+	Condition string `json:"condition"`
+	To        string `json:"to"`
+}
+
+// Represents a build manifest for sourcehut.
+type Manifest struct {
+	Image    string                `json:"image"`
+	Sources  []string              `json:"sources"`
+	Secrets  []string              `json:"secrets"`
+	Tasks    [](map[string]string) `json:"tasks"`
+	Triggers []Trigger             `json:"triggers"`
+}
+
+func prepareManifest(commit string) string {
+	m := Manifest{
+		Image:   "nixos/latest",
+		Sources: []string{"https://git.camden.tazj.in/"},
+
+		// secret for cachix/tazjin
+		Secrets: []string{"f7f02546-4d95-44f7-a98e-d61fdded8b5b"},
+
+		Tasks: [](map[string]string){
+			{"setup": `# sourcehut does not censor secrets in builds, hence this hack:
+echo -n 'export CACHIX_SIGNING_KEY=' >> ~/.buildenv
+cat ~/.cachix-tazjin >> ~/.buildenv
+nix-env -iA third_party.cachix -f git.tazj.in
+cachix use tazjin
+cd git.tazj.in
+git checkout ` + commit},
+
+			{"build": `cd git.tazj.in
+nix-build ci-builds.nix > built-paths`},
+
+			{"cache": `cd git.tazj.in
+cat built-paths | cachix push tazjin`},
+		},
+
+		Triggers: []Trigger{
+			Trigger{Action: "email", Condition: "failure", To: "mail@tazj.in"},
+		},
+	}
+
+	j, _ := json.Marshal(m)
+	return string(j)
+}
+
+// Trigger a build of a given branch & commit on builds.sr.ht
+func triggerBuild(log *syslog.Writer, token, branch, commit string) {
+	build := Build{
+		Manifest: prepareManifest(commit),
+		Note:     fmt.Sprintf("Build of 'master' at '%s'", commit),
+		Tags: []string{
+			// my branch names tend to contain slashes, which are not valid
+			// identifiers in sourcehut.
+			"depot", strings.ReplaceAll(branch, "/", "_"),
+		},
+	}
+
+	body, _ := json.Marshal(build)
+	reader := ioutil.NopCloser(bytes.NewReader(body))
+
+	req, err := http.NewRequest("POST", "https://builds.sr.ht/api/jobs", reader)
+	if err != nil {
+		log.Err(fmt.Sprintf("failed to create an HTTP request: %s", err))
+		os.Exit(1)
+	}
+
+	req.Header.Add("Authorization", "token "+token)
+	req.Header.Add("Content-Type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		// This might indicate a temporary error on the sourcehut side, do
+		// not fail the whole program.
+		log.Err(fmt.Sprintf("failed to send builds.sr.ht request:", err))
+		return
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		respBody, _ := ioutil.ReadAll(resp.Body)
+		log.Err(fmt.Sprintf("received non-success response from builds.sr.ht: %s (%v)", respBody, resp.Status))
+	} else {
+		fmt.Fprintf(log, "triggered builds.sr.ht job for branch '%s' at commit '%s'", branch, commit)
+	}
+}
+
+func parseRefUpdates() ([]refUpdate, error) {
+	var updates []refUpdate
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		line := scanner.Text()
+		fragments := strings.Split(line, " ")
+
+		if len(fragments) != 3 {
+			return nil, fmt.Errorf("invalid ref update: '%s'", line)
+		}
+
+		if !strings.HasPrefix(fragments[2], "refs/heads/") {
+			continue
+		}
+
+		updates = append(updates, refUpdate{
+			old:  fragments[0],
+			new:  fragments[1],
+			name: strings.TrimPrefix(fragments[2], "refs/heads/"),
+		})
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return updates, nil
+}
+
+func main() {
+	log, err := syslog.New(syslog.LOG_INFO|syslog.LOG_USER, "besadii")
+	if err != nil {
+		fmt.Printf("failed to open syslog: %s\n", err)
+		os.Exit(1)
+	}
+
+	// Before triggering builds, it is important that git
+	// update-server-info is run so that cgit correctly serves the
+	// repository.
+	err = exec.Command(gitBin, "update-server-info").Run()
+	if err != nil {
+		log.Alert("failed to run 'git update-server-info' for depot!")
+		os.Exit(1)
+	}
+
+	token, err := ioutil.ReadFile("/etc/secrets/srht-token")
+	if err != nil {
+		log.Alert("sourcehot token could not be read")
+		os.Exit(1)
+	}
+
+	updates, err := parseRefUpdates()
+	if err != nil {
+		log.Err(fmt.Sprintf("could not parse updated refs:", err))
+		os.Exit(1)
+	}
+
+	fmt.Fprintf(log, "triggering builds for %v refs", len(updates))
+
+	for _, update := range updates {
+		triggerBuild(log, string(token), update.name, update.new)
+	}
+}