chore(3p|nix): Remove typed Go r/2159

Nobody has actually done any experimentation with typed Go, so we're
getting rid of it for now - it's causing annoying IFD during build
graph generation.

Change-Id: Ibac3dea98ebed1b3ee08acda184d24c500cf695d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2458
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: Profpatsch <mail@profpatsch.de>

1 files changed, 316 insertions, 0 deletions

diff --git a/ops/besadii/main.go b/ops/besadii/main.go
new file mode 100644
index 000000000000..998c677010bc
--- /dev/null
+++ b/ops/besadii/main.go
@@ -0,0 +1,316 @@
+// Copyright 2019-2020 Google LLC.
+// SPDX-License-Identifier: Apache-2.0
+//
+// besadii is a small CLI tool that is invoked as a hook by various
+// programs to cause CI-related actions.
+//
+// It supports the following modes & operations:
+//
+// Gerrit (ref-updated) hook:
+// - Trigger Buildkite CI builds
+// - Trigger SourceGraph (cs.tvl.fyi) repository index updates
+//
+// Buildkite (post-command) hook:
+// - Submit CL verification status back to Gerrit
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log/syslog"
+	"net/http"
+	"os"
+	"path"
+	"regexp"
+)
+
+var branchRegexp = regexp.MustCompile(`^refs/heads/(.*)$`)
+var metaRegexp = regexp.MustCompile(`^refs/changes/\d{0,2}/(\d+)/meta$`)
+var patchsetRegexp = regexp.MustCompile(`^refs/changes/\d{0,2}/(\d+)/(\d+)$`)
+
+// refUpdated is a struct representing the information passed to
+// besadii when it is invoked as Gerrit's refUpdated hook.
+//
+// https://gerrit.googlesource.com/plugins/hooks/+/HEAD/src/main/resources/Documentation/hooks.md#ref_updated
+type refUpdated struct {
+	project   string
+	ref       string
+	commit    string
+	submitter string
+	email     string
+
+	changeId *string
+	patchset *string
+}
+
+type Author struct {
+	Name  string `json:"name"`
+	Email string `json:"email"`
+}
+
+// Build is the representation of a Buildkite build as described on
+// https://buildkite.com/docs/apis/rest-api/builds#create-a-build
+type Build struct {
+	Commit  string            `json:"commit"`
+	Branch  string            `json:"branch"`
+	Message string            `json:"message"`
+	Author  Author            `json:"author"`
+	Env     map[string]string `json:"env"`
+}
+
+// Trigger a build of a given branch & commit on Buildkite
+func triggerBuild(log *syslog.Writer, token string, update *refUpdated) error {
+	var message string
+	env := make(map[string]string)
+
+	if update.changeId != nil && update.patchset != nil {
+		env["GERRIT_CHANGE_ID"] = *update.changeId
+		env["GERRIT_PATCHSET"] = *update.patchset
+		message = fmt.Sprintf(":llama: depot @ https://cl.tvl.fyi/c/depot/+/%s/%s", *update.changeId, *update.patchset)
+	} else {
+		message = fmt.Sprintf(":llama: depot @ %s", update.commit)
+	}
+
+	build := Build{
+		Commit:  update.commit,
+		Branch:  update.ref,
+		Message: message,
+		Env:     env,
+		Author: Author{
+			Name:  update.submitter,
+			Email: update.email,
+		},
+	}
+
+	body, _ := json.Marshal(build)
+	reader := ioutil.NopCloser(bytes.NewReader(body))
+
+	req, err := http.NewRequest("POST", "https://api.buildkite.com/v2/organizations/tvl/pipelines/depot/builds", reader)
+	if err != nil {
+		return fmt.Errorf("failed to create an HTTP request: %w", err)
+	}
+
+	req.Header.Add("Authorization", "Bearer "+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 Buildkite side.
+		return fmt.Errorf("failed to send Buildkite request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 201 {
+		respBody, _ := ioutil.ReadAll(resp.Body)
+		log.Err(fmt.Sprintf("received non-success response from Buildkite: %s (%v)", respBody, resp.Status))
+	} else {
+		fmt.Fprintf(log, "triggered Buildkite build for ref %q at commit %q", update.ref, update.commit)
+	}
+
+	return nil
+}
+
+// Trigger a Sourcegraph repository index update on cs.tvl.fyi.
+//
+// https://docs.sourcegraph.com/admin/repo/webhooks
+func triggerIndexUpdate(token string) error {
+	req, err := http.NewRequest("POST", "https://cs.tvl.fyi/.api/repos/depot/-/refresh", nil)
+	if err != nil {
+		return err
+	}
+
+	req.Header.Add("Authorization", "token "+token)
+
+	_, err = http.DefaultClient.Do(req)
+	return err
+}
+
+func refUpdatedFromFlags() (*refUpdated, error) {
+	var update refUpdated
+
+	flag.StringVar(&update.project, "project", "", "Gerrit project")
+	flag.StringVar(&update.commit, "newrev", "", "new revision")
+	flag.StringVar(&update.email, "submitter", "", "Submitter email")
+	flag.StringVar(&update.submitter, "submitter-username", "", "Submitter username")
+	flag.StringVar(&update.ref, "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 string
+	flag.StringVar(&_old, "oldrev", "", "")
+
+	flag.Parse()
+
+	if update.project == "" || update.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" || metaRegexp.MatchString(update.ref) {
+		// this is not an error, but also not something we handle.
+		return nil, nil
+	}
+
+	if branchRegexp.MatchString(update.ref) {
+		// these refs don't need special handling, just move on
+		return &update, nil
+	}
+
+	if matches := patchsetRegexp.FindStringSubmatch(update.ref); matches != nil {
+		update.changeId = &matches[1]
+		update.patchset = &matches[2]
+		return &update, nil
+	}
+
+	return nil, fmt.Errorf("besadii does not support updates for this type of ref (%q)", update.ref)
+}
+
+func refUpdatedMain() {
+	// Logging happens in syslog for Gerrit hooks because we don't want
+	// the hook output to be intermingled with Gerrit's own output
+	// stream
+	log, err := syslog.New(syslog.LOG_INFO|syslog.LOG_USER, "besadii")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to open syslog: %s\n", err)
+		os.Exit(1)
+	}
+
+	update, err := refUpdatedFromFlags()
+	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'
+		log.Err("build triggers are only supported for the 'depot' project")
+		os.Exit(0)
+	}
+
+	buildkiteToken, err := ioutil.ReadFile("/etc/secrets/buildkite-besadii")
+	if err != nil {
+		log.Alert(fmt.Sprintf("buildkite token could not be read: %s", err))
+		os.Exit(1)
+	}
+
+	sourcegraphToken, err := ioutil.ReadFile("/etc/secrets/sourcegraph-token")
+	if err != nil {
+		log.Alert(fmt.Sprintf("sourcegraph token could not be read: %s", err))
+		os.Exit(1)
+	}
+
+	err = triggerBuild(log, string(buildkiteToken), update)
+	if err != nil {
+		log.Err(fmt.Sprintf("failed to trigger Buildkite build: %s", err))
+	}
+
+	err = triggerIndexUpdate(string(sourcegraphToken))
+	if err != nil {
+		log.Err(fmt.Sprintf("failed to trigger sourcegraph index update: %s", err))
+	}
+	log.Info("triggered sourcegraph index update")
+}
+
+// reviewInput is a struct representing the data submitted to Gerrit
+// to post a review on a CL.
+//
+// https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#review-input
+type reviewInput struct {
+	Message                        string         `json:"message"`
+	Labels                         map[string]int `json:"labels"`
+	OmitDuplicateComments          bool           `json:"omit_duplicate_comments"`
+	IgnoreDefaultAttentionSetRules bool           `json:"ignore_default_attention_set_rules"`
+}
+
+func postCommandMain() {
+	changeId := os.Getenv("GERRIT_CHANGE_ID")
+	patchset := os.Getenv("GERRIT_PATCHSET")
+
+	if changeId == "" || patchset == "" {
+		// If these variables are unset, but the hook was invoked, the
+		// build was most likely for a branch and not for a CL - no status
+		// needs to be reported back to Gerrit!
+		fmt.Println("This isn't a CL build, nothing to do. Have a nice day!")
+		return
+	}
+
+	if os.Getenv("BUILDKITE_LABEL") != ":duck:" {
+		// this is not the build stage, don't do anything.
+		return
+	}
+
+	gerritPassword, err := ioutil.ReadFile("/etc/secrets/buildkite-gerrit")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Gerrit password could not be read: %s", err)
+		os.Exit(1)
+	}
+
+	var verified int
+	var verb string
+
+	if os.Getenv("BUILDKITE_COMMAND_EXIT_STATUS") == "0" {
+		verified = 1 // Verified: +1 in Gerrit
+		verb = "passed"
+	} else {
+		verified = -1
+		verb = "failed"
+	}
+
+	msg := fmt.Sprintf("Build of patchset %s %s: %s", patchset, verb, os.Getenv("BUILDKITE_BUILD_URL"))
+	review := reviewInput{
+		Message:               msg,
+		OmitDuplicateComments: true,
+		Labels: map[string]int{
+			"Verified": verified,
+		},
+
+		// Update the attention set if we are failing this patchset.
+		IgnoreDefaultAttentionSetRules: verified == 1,
+	}
+
+	body, _ := json.Marshal(review)
+	reader := ioutil.NopCloser(bytes.NewReader(body))
+
+	url := fmt.Sprintf("https://cl.tvl.fyi/a/changes/%s/revisions/%s/review", changeId, patchset)
+	req, err := http.NewRequest("POST", url, reader)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to create an HTTP request: %w", err)
+		os.Exit(1)
+	}
+
+	req.SetBasicAuth("buildkite", string(gerritPassword))
+	req.Header.Add("Content-Type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		fmt.Errorf("failed to update CL on Gerrit: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		respBody, _ := ioutil.ReadAll(resp.Body)
+		fmt.Fprintf(os.Stderr, "received non-success response from Gerrit: %s (%v)", respBody, resp.Status)
+	} else {
+		fmt.Printf("Updated CI status on https://cl.tvl.fyi/c/depot/+/%s/%s", changeId, patchset)
+	}
+}
+
+func main() {
+	bin := path.Base(os.Args[0])
+
+	if bin == "ref-updated" {
+		refUpdatedMain()
+	} else if bin == "post-command" {
+		postCommandMain()
+	} else {
+		fmt.Fprintf(os.Stderr, "besadii does not know how to be invoked as %q, sorry!", bin)
+		os.Exit(1)
+	}
+}