g1t/services/pages/src/index.ts
Pick any line to see why it is the way it is: the commit, the pull request and issue it came from, and what the agent was thinking.
| Deployments: a preview for every pull request, production on g1t.page | 1 | /** |
| 2 | * The dispatcher for g1t.page: every app deployed by g1t is served here. | |
| 3 | * | |
| 4 | * The hostname's first label is the app's script name in the Workers for | |
| Projects live: fixes from walking them end to end | 5 | * Platforms namespace (`web-git-fix-login-acme.g1t.page` is the fix-login |
| 6 | * branch's preview of acme's web project), so a request needs no lookup: | |
| 7 | * the app is fetched by name and runs only for as long as it answers. An app no one visits | |
| Deployments: a preview for every pull request, production on g1t.page | 8 | * runs nothing and costs nothing. |
| 9 | * | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 10 | * Any other hostname is a project's custom domain, reaching here through |
| 11 | * Cloudflare for SaaS: the `DOMAINS` KV namespace, written by the | |
| 12 | * deployments service, names its app, or the hostname it redirects to. | |
| 13 | * | |
| Deployments: a preview for every pull request, production on g1t.page | 14 | * Kept apart from g1t.sh, so apps share no cookies or origin with the site |
| 15 | * people sign in to. | |
| 16 | */ | |
| 17 | ||
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 18 | import { DOMAIN, FALLBACK, parseEntry, redirectTo, route, type DomainEntry } from "./route.ts"; |
| 19 | ||
| Deployments: a preview for every pull request, production on g1t.page | 20 | type Env = { |
| 21 | APPS: DispatchNamespace; | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 22 | /** Custom hostname to `{ script, redirect }`. */ |
| 23 | DOMAINS?: KVNamespace; | |
| Deployments: a preview for every pull request, production on g1t.page | 24 | }; |
| 25 | ||
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 26 | /** How long a custom hostname's entry is kept in this isolate and at the edge. */ |
| 27 | const ENTRY_TTL_MS = 60 * 1000; | |
| 28 | const entries = new Map<string, { at: number; entry: DomainEntry | null }>(); | |
| Deployments: a preview for every pull request, production on g1t.page | 29 | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 30 | function page(status: number, title: string, body: string, site = DOMAIN): Response { |
| Deployments: a preview for every pull request, production on g1t.page | 31 | const html = `<!doctype html> |
| 32 | <html lang="en"> | |
| 33 | <head> | |
| 34 | <meta charset="utf-8"> | |
| 35 | <meta name="viewport" content="width=device-width, initial-scale=1"> | |
| 36 | <meta name="robots" content="noindex"> | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 37 | <title>${escape(title)} · ${escape(site)}</title> |
| Deployments: a preview for every pull request, production on g1t.page | 38 | <style> |
| 39 | :root { color-scheme: dark; --bg: #121214; --fg: #ececf1; --muted: #9a9aa6; --accent: #b4a7f5; } | |
| 40 | body { margin: 0; min-height: 100vh; display: grid; place-items: center; background: var(--bg); color: var(--fg); | |
| 41 | font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif; padding: 0 16px; } | |
| 42 | main { max-width: 32rem; } | |
| 43 | h1 { font-size: 1.5rem; margin: 0 0 .5rem; letter-spacing: -.01em; } | |
| 44 | p { color: var(--muted); margin: .5rem 0; } | |
| 45 | a { color: var(--accent); } | |
| 46 | code { font: .9em ui-monospace, SFMono-Regular, Menlo, monospace; color: var(--fg); } | |
| 47 | </style> | |
| 48 | </head> | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 49 | <body><main><h1>${escape(title)}</h1>${body}</main></body> |
| Deployments: a preview for every pull request, production on g1t.page | 50 | </html>`; |
| 51 | return new Response(html, { | |
| 52 | status, | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 53 | headers: { "content-type": "text/html; charset=utf-8", "x-robots-tag": "noindex", "cache-control": "no-store" }, |
| Deployments: a preview for every pull request, production on g1t.page | 54 | }); |
| 55 | } | |
| 56 | ||
| 57 | function escape(text: string): string { | |
| 58 | return text.replace(/[&<>"']/g, (c) => `&#${c.charCodeAt(0)};`); | |
| 59 | } | |
| 60 | ||
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 61 | /** A custom hostname's entry: from this isolate, else KV (cached at the edge too). */ |
| 62 | async function lookup(env: Env, hostname: string): Promise<DomainEntry | null> { | |
| 63 | const cached = entries.get(hostname); | |
| 64 | if (cached && Date.now() - cached.at < ENTRY_TTL_MS) return cached.entry; | |
| 65 | const value = env.DOMAINS ? await env.DOMAINS.get(hostname, { type: "json", cacheTtl: ENTRY_TTL_MS / 1000 }) : null; | |
| 66 | const entry = parseEntry(value); | |
| 67 | entries.set(hostname, { at: Date.now(), entry }); | |
| 68 | if (entries.size > 5000) entries.delete(entries.keys().next().value!); | |
| 69 | return entry; | |
| 70 | } | |
| 71 | ||
| 72 | /** Runs the app `script` for the request; `shown` is the address named in its error pages. */ | |
| 73 | async function dispatch(env: Env, request: Request, script: string, shown: string, missing: () => Response): Promise<Response> { | |
| 74 | let app: Fetcher; | |
| 75 | try { | |
| 76 | app = env.APPS.get(script); | |
| 77 | } catch { | |
| 78 | return missing(); | |
| 79 | } | |
| 80 | try { | |
| 81 | return await app.fetch(request); | |
| 82 | } catch (error) { | |
| 83 | if (/worker not found|script not found|does not exist/i.test(String(error))) return missing(); | |
| 84 | return page( | |
| 85 | 502, | |
| 86 | "The app failed", | |
| 87 | `<p>The app at <code>${escape(shown)}</code> threw an error before it could answer.</p>`, | |
| 88 | shown, | |
| 89 | ); | |
| 90 | } | |
| 91 | } | |
| 92 | ||
| Deployments: a preview for every pull request, production on g1t.page | 93 | export default { |
| 94 | async fetch(request: Request, env: Env): Promise<Response> { | |
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 95 | const host = new URL(request.url).hostname; |
| 96 | const where = route(host); | |
| 97 | switch (where.kind) { | |
| 98 | case "home": | |
| 99 | return page( | |
| 100 | 200, | |
| 101 | "g1t.page", | |
| 102 | `<p>Apps deployed by <a href="https://g1t.sh">g1t</a>: every pull request's preview, and each repository's production.</p> | |
| 103 | <p><a href="https://docs.g1t.sh/guides/deployments/">How deployments work</a></p>`, | |
| 104 | ); | |
| 105 | case "fallback": | |
| 106 | return page( | |
| 107 | 200, | |
| 108 | "Custom domains on g1t", | |
| 109 | `<p>Point a custom domain here, with a CNAME to <code>${FALLBACK}</code>, to serve a project's production on it. Add the domain first, under the project's Settings, Deployments, on g1t.</p> | |
| 110 | <p><a href="https://docs.g1t.sh/guides/deployments/#custom-domains">How custom domains work</a></p>`, | |
| 111 | ); | |
| 112 | case "invalid": | |
| 113 | return page(404, "Nothing here", "<p>This is not the address of an app on g1t.page.</p>"); | |
| 114 | case "custom": | |
| 115 | return custom(request, env, where.hostname); | |
| 116 | case "app": { | |
| 117 | const label = where.label; | |
| 118 | let response = await dispatch(env, request, label, `${label}.${DOMAIN}`, () => missing(label)); | |
| 119 | // Previews are for the people reviewing a change, not search engines. | |
| 120 | if (isPreview(label)) { | |
| 121 | response = new Response(response.body, response); | |
| 122 | response.headers.set("x-robots-tag", "noindex"); | |
| 123 | } | |
| 124 | return response; | |
| 125 | } | |
| Deployments: a preview for every pull request, production on g1t.page | 126 | } |
| 127 | }, | |
| 128 | } satisfies ExportedHandler<Env>; | |
| 129 | ||
| Agents and memory, checks and conflicts, profiles, slug renames, custom domains | 130 | /** A custom domain: its app, or a 308 to the hostname it is paired with. */ |
| 131 | async function custom(request: Request, env: Env, hostname: string): Promise<Response> { | |
| 132 | let entry: DomainEntry | null; | |
| 133 | try { | |
| 134 | entry = await lookup(env, hostname); | |
| 135 | } catch (error) { | |
| 136 | console.error("could not read domain", hostname, error); | |
| 137 | return page(503, "Try again in a moment", `<p><code>${escape(hostname)}</code> could not be looked up just now.</p>`, hostname); | |
| 138 | } | |
| 139 | if (!entry) { | |
| 140 | return page( | |
| 141 | 404, | |
| 142 | "This domain is not set up", | |
| 143 | `<p><code>${escape(hostname)}</code> points at g1t, but no project serves it. Its owner adds it under the project's Settings, Deployments, on <a href="https://g1t.sh">g1t</a>.</p>`, | |
| 144 | hostname, | |
| 145 | ); | |
| 146 | } | |
| 147 | if (entry.redirect && entry.redirect !== hostname) { | |
| 148 | return new Response(null, { | |
| 149 | status: 308, | |
| 150 | headers: { location: redirectTo(request.url, entry.redirect), "cache-control": "public, max-age=300" }, | |
| 151 | }); | |
| 152 | } | |
| 153 | return dispatch(env, request, entry.script, hostname, () => | |
| 154 | page( | |
| 155 | 404, | |
| 156 | "Nothing deployed here yet", | |
| 157 | `<p><code>${escape(hostname)}</code> serves a project's production, and it is not up. Deploying the project brings it here.</p>`, | |
| 158 | hostname, | |
| 159 | ), | |
| 160 | ); | |
| 161 | } | |
| 162 | ||
| Projects live: fixes from walking them end to end | 163 | /** A branch's preview: `<project>-git-<branch>-<workspace>`. */ |
| 164 | function isPreview(label: string): boolean { | |
| 165 | return label.includes("-git-"); | |
| 166 | } | |
| 167 | ||
| Deployments: a preview for every pull request, production on g1t.page | 168 | function missing(label: string): Response { |
| Projects live: fixes from walking them end to end | 169 | const preview = isPreview(label); |
| Deployments: a preview for every pull request, production on g1t.page | 170 | return page( |
| 171 | 404, | |
| 172 | preview ? "This preview is not up" : "Nothing deployed here", | |
| 173 | preview | |
| Projects live: fixes from walking them end to end | 174 | ? `<p>A preview comes down when its pull request is closed or merged, or after its project's idle days without a visit. Pushing to the branch, or redeploying it from the project's Deployments page, brings it back.</p>` |
| 175 | : `<p>No app is deployed at <code>${escape(label)}.${DOMAIN}</code>. Deployments are turned on per project, from its Settings on g1t.</p>`, | |
| Deployments: a preview for every pull request, production on g1t.page | 176 | ); |
| 177 | } |