Blame · Line-by-line history

`preview-builder.ts`

Each line is annotated with the commit that last touched it. Click any SHA to jump to that commit and see the surrounding change.

preview-builder.tsBlame312 lines · 1 contributor

Normal view Raw

1df50d5Claude	1	/**
	2	* PR preview builder (migration 0077).
	3	*
	4	* When a PR is opened or updated and the repo has `preview_build_command`
	5	* configured, this module:
	6	* 1. Clones the PR's head branch into /tmp/previews/<prId>-<shortSha>
	7	* 2. Runs the configured build command with a 2-minute timeout
	8	* 3. Captures stdout + stderr as the build log
	9	* 4. On success: marks the pr_previews row as 'ready' and posts a PR comment
	10	* 5. On failure: marks it 'failed' and stores the log
	11	*
	12	* Feature flag: preview builds only run when PREVIEW_DOMAIN env var is set
	13	* AND the repo has preview_build_command configured.
	14	*
	15	* Philosophy: never throw — every DB + subprocess call is wrapped in
	16	* try/catch so a failure cannot disrupt the PR creation path. Callers use
	17	* `buildPreview(...).catch(() => {})` fire-and-forget style.
	18	*/
	19
	20	import { eq, and } from "drizzle-orm";
	21	import { db } from "../db";
	22	import {
	23	repositories,
	24	pullRequests,
	25	prPreviews,
	26	prComments,
	27	users,
	28	} from "../db/schema";
	29	import { config } from "./config";
	30
	31	const PREVIEW_BUILD_DIR = process.env.PREVIEW_BUILD_DIR \|\| "/tmp/previews";
	32	const BUILD_TIMEOUT_MS = 2 * 60 * 1_000; // 2 minutes
	33
	34	// ─── helpers ────────────────────────────────────────────────────────────────
	35
	36	/** Slugify a string for use in a URL path segment. */
	37	function slug(s: string): string {
	38	return (s \|\| "")
	39	.toLowerCase()
	40	.replace(/[^a-z0-9]+/g, "-")
	41	.replace(/^-+\|-+$/g, "")
	42	.slice(0, 60);
	43	}
	44
	45	/** Compute the public URL for a built preview. */
	46	export function previewBuilderUrl(
	47	ownerName: string,
	48	repoName: string,
	49	branchName: string
	50	): string {
	51	const domain = config.previewDomain \|\| config.appBaseUrl;
	52	return `${domain}/previews/${ownerName}/${repoName}/${slug(branchName)}/`;
	53	}
	54
	55	/** The on-disk directory where built output lives. */
	56	export function previewBuildPath(
	57	prId: string,
	58	headSha: string,
	59	outputDir: string
	60	): string {
	61	const shortSha = headSha.slice(0, 8);
	62	return `${PREVIEW_BUILD_DIR}/${slug(prId)}-${shortSha}/${outputDir}`;
	63	}
	64
	65	// ─── core builder ───────────────────────────────────────────────────────────
	66
	67	/**
	68	* Build a preview for the given PR. Fire-and-forget by callers:
	69	* `buildPreview(prId, repoId, headSha).catch(() => {})`
	70	*/
	71	export async function buildPreview(
	72	prId: string,
	73	repoId: string,
	74	headSha: string
	75	): Promise<void> {
	76	// Feature flag: only run when PREVIEW_DOMAIN is set
	77	if (!config.previewDomain) return;
	78
	79	// ── look up the repo for build config ──
	80	let repo: {
	81	id: string;
	82	name: string;
	83	ownerId: string;
	84	previewBuildCommand: string \| null;
	85	previewOutputDir: string \| null;
	86	diskPath: string;
	87	} \| null = null;
	88
	89	let ownerUsername = "";
	90
	91	try {
	92	const [row] = await db
	93	.select({
	94	id: repositories.id,
	95	name: repositories.name,
	96	ownerId: repositories.ownerId,
	97	previewBuildCommand: repositories.previewBuildCommand,
	98	previewOutputDir: repositories.previewOutputDir,
	99	diskPath: repositories.diskPath,
	100	})
	101	.from(repositories)
	102	.where(eq(repositories.id, repoId))
	103	.limit(1);
	104	if (!row) return;
	105	repo = row;
	106
	107	// Resolve owner username for URL construction
	108	const [ownerRow] = await db
	109	.select({ username: users.username })
	110	.from(users)
	111	.where(eq(users.id, repo.ownerId))
	112	.limit(1);
	113	ownerUsername = ownerRow?.username ?? "";
	114	} catch (err) {
	115	console.warn("[preview-builder] repo lookup failed:", err instanceof Error ? err.message : err);
	116	return;
	117	}
	118
	119	// Opt-in gate: skip if no build command configured
	120	if (!repo.previewBuildCommand) return;
	121
	122	// ── look up the PR for branch name ──
	123	let pr: { id: string; headBranch: string; number: number } \| null = null;
	124	try {
	125	const [row] = await db
	126	.select({ id: pullRequests.id, headBranch: pullRequests.headBranch, number: pullRequests.number })
	127	.from(pullRequests)
	128	.where(eq(pullRequests.id, prId))
	129	.limit(1);
	130	if (!row) return;
	131	pr = row;
	132	} catch (err) {
	133	console.warn("[preview-builder] pr lookup failed:", err instanceof Error ? err.message : err);
	134	return;
	135	}
	136
	137	const buildCommand = repo.previewBuildCommand;
	138	const outputDir = repo.previewOutputDir \|\| "dist";
	139	const shortSha = headSha.slice(0, 8);
	140	const previewUrl = previewBuilderUrl(ownerUsername, repo.name, pr.headBranch);
	141	const buildDir = `${PREVIEW_BUILD_DIR}/${slug(prId)}-${shortSha}`;
	142
	143	// ── upsert preview row to 'building' ──
	144	let previewRowId: number \| null = null;
	145	try {
	146	const [row] = await db
	147	.insert(prPreviews)
	148	.values({
	149	repoId,
	150	prId,
	151	branchName: pr.headBranch,
	152	headSha,
	153	status: "building",
	154	previewUrl,
	155	buildCommand,
	156	outputDir,
	157	createdAt: new Date(),
	158	updatedAt: new Date(),
	159	})
	160	.onConflictDoNothing()
	161	.returning({ id: prPreviews.id });
	162	// If there's already a row (same prId+headSha isn't unique, but let's handle it)
	163	if (row) {
	164	previewRowId = row.id;
	165	} else {
	166	// Find existing
	167	const [existing] = await db
	168	.select({ id: prPreviews.id })
	169	.from(prPreviews)
	170	.where(and(eq(prPreviews.prId, prId), eq(prPreviews.headSha, headSha)))
	171	.limit(1);
	172	previewRowId = existing?.id ?? null;
	173	}
	174	} catch (err) {
	175	console.warn("[preview-builder] insert failed:", err instanceof Error ? err.message : err);
	176	return;
	177	}
	178
	179	// ── clone + build ──
	180	const buildStart = Date.now();
	181	let buildLog = "";
	182	let buildOk = false;
	183
	184	try {
	185	// Step 1: clone the bare repo and checkout the head branch
	186	const cloneProc = Bun.spawn(
	187	["git", "clone", "--branch", pr.headBranch, "--depth", "1", repo.diskPath, buildDir],
	188	{ stderr: "pipe", stdout: "pipe" }
	189	);
	190
	191	const cloneStdout = await new Response(cloneProc.stdout).text();
	192	const cloneStderr = await new Response(cloneProc.stderr).text();
	193	await cloneProc.exited;
	194
	195	buildLog += `=== clone ===\n${cloneStdout}${cloneStderr}\n`;
	196
	197	if (cloneProc.exitCode !== 0) {
	198	throw new Error(`git clone failed (exit ${cloneProc.exitCode}): ${cloneStderr.slice(0, 500)}`);
	199	}
	200
	201	// Step 2: run the build command with timeout
	202	const buildProc = Bun.spawn(
	203	["sh", "-c", buildCommand],
	204	{
	205	cwd: buildDir,
	206	stderr: "pipe",
	207	stdout: "pipe",
	208	env: { ...process.env, CI: "1" },
	209	}
	210	);
	211
	212	// Apply 2-minute timeout
	213	const timeoutHandle = setTimeout(() => {
	214	try { buildProc.kill(); } catch {}
	215	}, BUILD_TIMEOUT_MS);
	216
	217	const buildStdout = await new Response(buildProc.stdout).text();
	218	const buildStderr = await new Response(buildProc.stderr).text();
	219	await buildProc.exited;
	220	clearTimeout(timeoutHandle);
	221
	222	buildLog += `\n=== build: ${buildCommand} ===\n${buildStdout}${buildStderr}\n`;
	223
	224	if (buildProc.exitCode !== 0) {
	225	throw new Error(`build command failed (exit ${buildProc.exitCode})`);
	226	}
	227
	228	buildOk = true;
	229	} catch (err) {
	230	buildLog += `\n=== error ===\n${err instanceof Error ? err.message : String(err)}\n`;
	231	}
	232
	233	const durationMs = Date.now() - buildStart;
	234
	235	// ── update preview row ──
	236	try {
	237	if (previewRowId !== null) {
	238	await db
	239	.update(prPreviews)
	240	.set({
	241	status: buildOk ? "ready" : "failed",
	242	buildLog: buildLog.slice(0, 50_000),
	243	previewUrl: buildOk ? previewUrl : null,
	244	buildDurationMs: durationMs,
	245	updatedAt: new Date(),
	246	})
	247	.where(eq(prPreviews.id, previewRowId));
	248	}
	249	} catch (err) {
	250	console.warn("[preview-builder] update failed:", err instanceof Error ? err.message : err);
	251	}
	252
	253	// ── post a PR comment with the result ──
	254	try {
	255	// Use the system bot user (first admin user, or fall back to the PR author)
	256	const [authorRow] = await db
	257	.select({ authorId: pullRequests.authorId })
	258	.from(pullRequests)
	259	.where(eq(pullRequests.id, prId))
	260	.limit(1);
	261
	262	if (authorRow) {
	263	const buildTimeS = Math.round(durationMs / 1000);
	264	const body = buildOk
	265	? `🚀 Preview deployed\nURL: ${previewUrl}\nBuilt from: \`${shortSha}\`\nBuild time: ${buildTimeS}s`
	266	: `❌ Preview build failed\nCommit: \`${shortSha}\`\nBuild time: ${buildTimeS}s\n\nSee build log in the [Previews tab](/${ownerUsername}/${repo.name}/previews).`;
	267
	268	await db.insert(prComments).values({
	269	pullRequestId: prId,
	270	authorId: authorRow.authorId,
	271	body,
	272	isAiReview: false,
	273	moderationStatus: "approved",
	274	createdAt: new Date(),
	275	updatedAt: new Date(),
	276	});
	277	}
	278	} catch (err) {
	279	console.warn("[preview-builder] comment failed:", err instanceof Error ? err.message : err);
	280	}
	281	}
	282
	283	/**
	284	* Look up the most recent pr_previews row for a given PR.
	285	* Returns null if none exists or the table doesn't exist yet.
	286	*/
	287	export async function getPreviewForPr(prId: string): Promise<{
	288	id: number;
	289	status: string;
	290	previewUrl: string \| null;
	291	headSha: string;
	292	buildDurationMs: number \| null;
	293	} \| null> {
	294	if (!prId) return null;
	295	try {
	296	const [row] = await db
	297	.select({
	298	id: prPreviews.id,
	299	status: prPreviews.status,
	300	previewUrl: prPreviews.previewUrl,
	301	headSha: prPreviews.headSha,
	302	buildDurationMs: prPreviews.buildDurationMs,
	303	})
	304	.from(prPreviews)
	305	.where(eq(prPreviews.prId, prId))
	306	.orderBy(prPreviews.id)
	307	.limit(1);
	308	return row ?? null;
	309	} catch {
	310	return null;
	311	}
	312	}