feat(backend): add a packages discoverer to get packages from repos

Author: WarningImHack3r

src/lib/repositories.ts

@@ -128,9 +128,28 @@ type Entries<T> = {
 export const repositories = Object.entries(repos) as unknown as Entries<typeof repos>;
 
 /**
- * Get all a record of all GitHub repositories
- * from the collection.
+ * Get a record of all GitHub repositories
+ * from the collection, as an "owner-to-repo-names"
+ * map.
  */
 export const githubRepos = {
 	sveltejs: [...new Set(repositories.flatMap(([, { repos }]) => repos.map(r => r.repoName)))]
 };
+
+/**
+ * Get a list of objects containing
+ * the repo owner, the repo name, and the
+ * associated transformation function to
+ * transform a release tag name into a package
+ * name.
+ */
+export const transformationRepos = repositories.flatMap(([, { repos }]) =>
+	repos.map(r => ({
+		owner: "sveltejs",
+		repoName: r.repoName,
+		tagToName: (tag: string) => {
+			const [name] = r.metadataFromTag(tag);
+			return name;
+		}
+	}))
+);

src/lib/server/github-cache.ts

@@ -214,6 +214,13 @@ export class SvelteGitHubCache {
 	async deleteEntry(repo: string) {
 		await this.#cache.deleteEntry(this.#owner, repo);
 	}
+
+	/**
+	 * A convenience getter for the underlying cache
+	 */
+	get cache() {
+		return this.#cache;
+	}
 }
 
 export const svelteGitHubCache = new SvelteGitHubCache(

src/lib/server/package-discoverer.ts

@@ -0,0 +1,77 @@
+import { GitHubCache, svelteGitHubCache } from "./github-cache";
+import { transformationRepos } from "$lib/repositories";
+
+export class PackageDiscoverer {
+	readonly #cache: GitHubCache;
+	readonly #repos: { owner: string; repoName: string; tagToName: (name: string) => string }[];
+	#packages: { owner: string; repoName: string; packages: string[] }[] = [];
+
+	constructor(
+		cache: GitHubCache,
+		repos: { owner: string; repoName: string; tagToName: (name: string) => string }[]
+	) {
+		this.#cache = cache;
+		this.#repos = repos;
+	}
+
+	/**
+	 * Discover the packages from the passed releases
+	 * and replaces/adds it to the #packages array from
+	 * the owner and repo name.
+	 *
+	 * @param owner the owner of the repository to use to populate the array
+	 * @param repoName the name of the repository to use to populate the array
+	 * @param releases the releases to populate the array from
+	 */
+	async discoverReleases(
+		owner: string,
+		repoName: string,
+		releases: Awaited<ReturnType<InstanceType<typeof GitHubCache>["getReleases"]>>
+	) {
+		// 1. Find the transformation function in the existing repos, exit otherwise
+		const repo = this.#repos.find(({ owner: o, repoName: n }) => o == owner && repoName == n);
+		if (!repo) return;
+		// 2. Compute the unique packages
+		const uniquePackages = [...new Set(releases.map(({ tag_name }) => repo.tagToName(tag_name)))];
+		// 3. Replace or add the value in the array
+		for (const [i, { owner: o, repoName: n }] of this.#packages.entries()) {
+			if (o === owner && repoName == n) {
+				this.#packages[i]!.packages = uniquePackages;
+				return;
+			}
+		}
+		this.#packages.push({ owner, repoName, packages: uniquePackages });
+	}
+
+	/**
+	 * A processing-heavy function that discovers all the
+	 * packages for the given #repos.
+	 * Populates the result into #packages.
+	 */
+	async discoverAll() {
+		this.#packages = await Promise.all(
+			this.#repos.map(async ({ owner, repoName, tagToName }) => {
+				const releases = await this.#cache.getReleases(owner, repoName);
+				const packages = [...new Set(releases.map(({ tag_name }) => tagToName(tag_name)))];
+				return { owner, repoName, packages };
+			})
+		);
+	}
+
+	/**
+	 * Returns the saved #packages if they're not empty,
+	 * otherwise calls {@link discoverAll} then returns the
+	 * #packages.
+	 *
+	 * @returns all the discovered packages per repo name
+	 */
+	async getOrDiscover() {
+		if (this.#packages.length) {
+			return this.#packages;
+		}
+		await this.discoverAll();
+		return this.#packages;
+	}
+}
+
+export const discoverer = new PackageDiscoverer(svelteGitHubCache.cache, transformationRepos);

src/routes/cron/+server.ts

@@ -1,16 +1,22 @@
 import { error, type RequestHandler } from "@sveltejs/kit";
 import { CRON_SECRET } from "$env/static/private";
 import { svelteGitHubCache } from "$lib/server/github-cache";
+import { discoverer } from "$lib/server/package-discoverer";
 import { githubRepos } from "$lib/repositories";
 
 export const GET: RequestHandler = async ({ request }) => {
 	if (request.headers.get("Authorization") !== `Bearer ${CRON_SECRET}`) {
 		error(401);
 	}
 
-	for (const repo of githubRepos.sveltejs) {
-		await svelteGitHubCache.fetchAndCacheReleases(repo);
-	}
+	await Promise.all(
+		Object.entries(githubRepos).flatMap(([owner, repos]) =>
+			repos.map(async repo => {
+				const releases = await svelteGitHubCache.fetchAndCacheReleases(repo);
+				await discoverer.discoverReleases(owner, repo, releases);
+			})
+		)
+	);
 
 	return new Response();
 };