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preview-builder.ts
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| 1df50d5 | 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 | |
| 5e0d7ba | 202 | // `buildCommand` is repo.previewBuildCommand — a value any repo owner sets |
| 203 | // from the repo settings form. It was executed with the FULL process.env, | |
| 204 | // and stdout/stderr is captured into buildLog and rendered back to that | |
| 205 | // same user. So `previewBuildCommand = "env"` printed DATABASE_URL (the | |
| 206 | // production Neon credentials), ANTHROPIC_API_KEY, GLUECRON_PAT, | |
| 207 | // WORKFLOW_SECRETS_KEY, SERVER_TARGETS_KEY and the OAuth secrets straight | |
| 208 | // into a page the attacker controls. Complete platform compromise from a | |
| 209 | // settings field. | |
| 210 | // | |
| 211 | // Use the same curated allowlist the workflow runner already uses for | |
| 212 | // user-supplied `run:` steps — identical threat model, so it should never | |
| 213 | // have been a separate decision. | |
| 214 | const { buildRunnerEnv } = await import("./workflow-runner"); | |
| 1df50d5 | 215 | const buildProc = Bun.spawn( |
| 216 | ["sh", "-c", buildCommand], | |
| 217 | { | |
| 218 | cwd: buildDir, | |
| 219 | stderr: "pipe", | |
| 220 | stdout: "pipe", | |
| 5e0d7ba | 221 | env: buildRunnerEnv({ CI: "1" }), |
| 1df50d5 | 222 | } |
| 223 | ); | |
| 224 | ||
| 225 | // Apply 2-minute timeout | |
| 226 | const timeoutHandle = setTimeout(() => { | |
| 227 | try { buildProc.kill(); } catch {} | |
| 228 | }, BUILD_TIMEOUT_MS); | |
| 229 | ||
| 230 | const buildStdout = await new Response(buildProc.stdout).text(); | |
| 231 | const buildStderr = await new Response(buildProc.stderr).text(); | |
| 232 | await buildProc.exited; | |
| 233 | clearTimeout(timeoutHandle); | |
| 234 | ||
| 235 | buildLog += `\n=== build: ${buildCommand} ===\n${buildStdout}${buildStderr}\n`; | |
| 236 | ||
| 237 | if (buildProc.exitCode !== 0) { | |
| 238 | throw new Error(`build command failed (exit ${buildProc.exitCode})`); | |
| 239 | } | |
| 240 | ||
| 241 | buildOk = true; | |
| 242 | } catch (err) { | |
| 243 | buildLog += `\n=== error ===\n${err instanceof Error ? err.message : String(err)}\n`; | |
| 244 | } | |
| 245 | ||
| 246 | const durationMs = Date.now() - buildStart; | |
| 247 | ||
| 248 | // ── update preview row ── | |
| 249 | try { | |
| 250 | if (previewRowId !== null) { | |
| 251 | await db | |
| 252 | .update(prPreviews) | |
| 253 | .set({ | |
| 254 | status: buildOk ? "ready" : "failed", | |
| 255 | buildLog: buildLog.slice(0, 50_000), | |
| 256 | previewUrl: buildOk ? previewUrl : null, | |
| 257 | buildDurationMs: durationMs, | |
| 258 | updatedAt: new Date(), | |
| 259 | }) | |
| 260 | .where(eq(prPreviews.id, previewRowId)); | |
| 261 | } | |
| 262 | } catch (err) { | |
| 263 | console.warn("[preview-builder] update failed:", err instanceof Error ? err.message : err); | |
| 264 | } | |
| 265 | ||
| 266 | // ── post a PR comment with the result ── | |
| 267 | try { | |
| 268 | // Use the system bot user (first admin user, or fall back to the PR author) | |
| 269 | const [authorRow] = await db | |
| 270 | .select({ authorId: pullRequests.authorId }) | |
| 271 | .from(pullRequests) | |
| 272 | .where(eq(pullRequests.id, prId)) | |
| 273 | .limit(1); | |
| 274 | ||
| 275 | if (authorRow) { | |
| 276 | const buildTimeS = Math.round(durationMs / 1000); | |
| 277 | const body = buildOk | |
| 278 | ? `🚀 **Preview deployed**\nURL: ${previewUrl}\nBuilt from: \`${shortSha}\`\nBuild time: ${buildTimeS}s` | |
| 279 | : `❌ **Preview build failed**\nCommit: \`${shortSha}\`\nBuild time: ${buildTimeS}s\n\nSee build log in the [Previews tab](/${ownerUsername}/${repo.name}/previews).`; | |
| 280 | ||
| 281 | await db.insert(prComments).values({ | |
| 282 | pullRequestId: prId, | |
| 283 | authorId: authorRow.authorId, | |
| 284 | body, | |
| 285 | isAiReview: false, | |
| 286 | moderationStatus: "approved", | |
| 287 | createdAt: new Date(), | |
| 288 | updatedAt: new Date(), | |
| 289 | }); | |
| 290 | } | |
| 291 | } catch (err) { | |
| 292 | console.warn("[preview-builder] comment failed:", err instanceof Error ? err.message : err); | |
| 293 | } | |
| 294 | } | |
| 295 | ||
| 296 | /** | |
| 297 | * Look up the most recent pr_previews row for a given PR. | |
| 298 | * Returns null if none exists or the table doesn't exist yet. | |
| 299 | */ | |
| 300 | export async function getPreviewForPr(prId: string): Promise<{ | |
| 301 | id: number; | |
| 302 | status: string; | |
| 303 | previewUrl: string | null; | |
| 304 | headSha: string; | |
| 305 | buildDurationMs: number | null; | |
| 306 | } | null> { | |
| 307 | if (!prId) return null; | |
| 308 | try { | |
| 309 | const [row] = await db | |
| 310 | .select({ | |
| 311 | id: prPreviews.id, | |
| 312 | status: prPreviews.status, | |
| 313 | previewUrl: prPreviews.previewUrl, | |
| 314 | headSha: prPreviews.headSha, | |
| 315 | buildDurationMs: prPreviews.buildDurationMs, | |
| 316 | }) | |
| 317 | .from(prPreviews) | |
| 318 | .where(eq(prPreviews.prId, prId)) | |
| 319 | .orderBy(prPreviews.id) | |
| 320 | .limit(1); | |
| 321 | return row ?? null; | |
| 322 | } catch { | |
| 323 | return null; | |
| 324 | } | |
| 325 | } |