blog-go-postgres/extras/auth-clerk

Clerk auth (drop-in)

Replaces the template's local email/password auth with Clerk session tokens. Users sign up and sign in through Clerk (hosted pages or one of its frontend SDKs); this API only verifies the session JWT Clerk issues.

clerk.go validates Authorization: Bearer <token> against your Clerk instance's JWKS endpoint (RS256 signature, issuer, expiry, azp) and exposes the Clerk user id via userID(r) — the same helper the local setup provides, so the post handlers keep working.

Swap steps

1. Copy clerk.go into the project root and change package clerkauth to package main.

2. Delete auth.go — register, login, and HS256 tokens are Clerk's job now.

3. In main.go, drop the AUTH_SECRET lookup (and the secret field on app), drop the /auth/register and /auth/login routes, and wrap the protected routes with the Clerk middleware:

   requireAuth := newClerkAuth()
   mux.HandleFunc("POST /posts", requireAuth(a.createPost))
   mux.HandleFunc("PUT /posts/{id}", requireAuth(a.updatePost))
   mux.HandleFunc("DELETE /posts/{id}", requireAuth(a.deletePost))
   

4. Author ids are now Clerk user ids (strings like user_2f...), not integers:

   • in schema.sql, drop the users table and change posts.author_id to TEXT NOT NULL (no foreign key) — then reset the database (docker compose down, delete ./data) so the new schema applies;
   • in posts.go, change the post.AuthorID field to string and use userID(r) directly instead of strconv.ParseInt(userID(r), 10, 64).

5. Environment: remove AUTH_SECRET, add your instance's issuer and the origins allowed to mint tokens for this API (checked against the azp claim; leave it unset to skip the check):

   CLERK_ISSUER=https://your-app.clerk.accounts.dev
   CLERK_AUTHORIZED_PARTIES=https://your-site.com,http://localhost:5173
   

   The issuer is your Frontend API URL (Clerk dashboard → API keys); production instances use your own domain, e.g. https://clerk.your-site.com.

After the swap go vet ./... should pass and every (auth) route expects a Clerk session JWT.