chore(besadii): Make besadii a Go2 project r/1018

Change-Id: Id5aef73b131252fb9c880dd95fc72bfe083f1b75

1 files changed, 202 insertions, 0 deletions

diff --git a/ops/besadii/main.go2 b/ops/besadii/main.go2
new file mode 100644
index 000000000000..43059565242e
--- /dev/null
+++ b/ops/besadii/main.go2
@@ -0,0 +1,202 @@
+// Copyright 2019-2020 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 Gerrit hook (ref-updated).
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log/syslog"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+)
+
+var branchPrefix = "refs/heads/"
+
+// Represents an updated branch, as passed to besadii by Gerrit.
+//
+// https://gerrit.googlesource.com/plugins/hooks/+/HEAD/src/main/resources/Documentation/hooks.md#ref_updated
+type branchUpdate struct {
+	project   string
+	branch    string
+	commit    string
+	submitter 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
+// https://man.sr.ht/builds.sr.ht/triggers.md
+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://code.tvl.fyi/"},
+
+		// 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 code.tvl.fyi
+cachix use tazjin
+cd code.tvl.fyi
+git checkout ` + commit},
+
+			{"build": `cd code.tvl.fyi
+nix-build ci-builds.nix > built-paths`},
+
+			{"cache": `cd code.tvl.fyi
+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 string, update *branchUpdate) {
+	build := Build{
+		Manifest: prepareManifest(update.commit),
+		Note:     fmt.Sprintf("build of %q at %q, submitted by %q", update.branch, update.commit, update.submitter),
+		Tags: []string{
+			// my branch names tend to contain slashes, which are not valid
+			// identifiers in sourcehut.
+			"depot", strings.ReplaceAll(update.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 %q at commit %q", update.branch, update.commit)
+	}
+}
+
+func branchUpdateFromFlags() (*branchUpdate, error) {
+	if path.Base(os.Args[0]) != "ref-updated" {
+		return nil, fmt.Errorf("besadii must be invoked as the 'ref-updated' hook")
+	}
+
+	var update branchUpdate
+
+	flag.StringVar(&update.project, "project", "", "Gerrit project")
+	flag.StringVar(&update.commit, "newrev", "", "new revision")
+	flag.StringVar(&update.submitter, "submitter-username", "", "Submitter username")
+	ref := flag.String("refname", "", "updated reference name")
+
+	// Gerrit passes more flags than we want, but Rob Pike decided[0] in
+	// 2013 that the Go art project will not allow users to ignore flags
+	// because he "doesn't like it". The following code ignores the
+	// flags.
+	//
+	// [0]: https://github.com/golang/go/issues/6112#issuecomment-66083768
+	var _old, _submitter string
+	flag.StringVar(&_old, "oldrev", "", "")
+	flag.StringVar(&_submitter, "submitter", "", "")
+
+	flag.Parse()
+
+	if update.project == "" || *ref == "" || update.commit == "" || update.submitter == "" {
+		// If we get here, the user is probably being a dummy and invoking
+		// this manually - but incorrectly.
+		return nil, fmt.Errorf("'ref-updated' hook invoked without required arguments")
+	}
+
+	if update.project != "depot" {
+		// this is not an error, but also not something we handle.
+		return nil, nil
+	}
+
+	if !strings.HasPrefix(*ref, branchPrefix) {
+		return nil, fmt.Errorf("besadii only supports branch updates at the moment")
+	}
+
+	update.branch = strings.TrimPrefix(*ref, branchPrefix)
+
+	return &update, 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)
+	}
+
+	token, err := ioutil.ReadFile("/etc/secrets/srht-token")
+	if err != nil {
+		log.Alert("sourcehot token could not be read")
+		os.Exit(1)
+	}
+
+	update, err := branchUpdateFromFlags()
+	if err != nil {
+		log.Err(fmt.Sprintf("failed to parse ref update: %s", err))
+		os.Exit(1)
+	}
+
+	if update == nil { // the project was not 'depot'
+		os.Exit(0)
+	}
+
+	triggerBuild(log, string(token), update)
+}