flyio-cli

# Fly.io (flyctl) CLI Operate Fly.io apps safely and repeatably with `flyctl`. ## Defaults / safety - Prefer **read-only** commands first: `fly status`, `fly logs`, `fly config show`, `fly releases`, `fly secrets list`. - **Do not edit/modify Fly.io apps, machines, secrets, volumes, or databases without your human’s explicit approval.** - Read-only actions are OK without approval. - Destructive actions (destroy/drop) always require explicit approval. - When debugging builds, capture the exact error output and determine whether it’s a: - build/packaging issue (Dockerfile, Gemfile.lock platforms, assets precompile) - runtime issue (secrets, DB, migrations) - platform issue (regions, machines, health checks) ## Quick start (typical deploy) From the app repo directory: 1) Confirm which app you’re targeting - `fly app list` - `fly status -a <app>` - Check `fly.toml` for `app = "..."` 2) Validate / inspect (read-only) - `fly status -a <app>` - `fly logs -a <app>` - `fly config show -a <app>` (Deploys are in **High-risk operations** below and require explicit user approval.) ## Debugging deploy/build failures ### Common checks - `fly deploy --verbose` (more build logs) - If using Dockerfile builds: verify Dockerfile Ruby/version and Gemfile.lock platforms match your builder OS/arch. ### Rails + Docker + native gems (nokogiri, pg, etc.) Symptoms: Bundler can’t find a platform gem like `nokogiri-…-x86_64-linux` during build. Fix pattern: - Ensure `Gemfile.lock` includes the Linux platform used by Fly’s builder (usually `x86_64-linux`). - Example: `bundle lock --add-platform x86_64-linux` - Ensure Dockerfile’s Ruby version matches `.ruby-version`. (See `references/rails-docker-builds.md`.) ## Logs & config (read-only) - Stream logs: - `fly logs -a <app>` - Show config: - `fly config show -a <app>` - List secrets (names only): - `fly secrets list -a <app>` ## High-risk operations (ask first) These commands can execute arbitrary code on servers or mutate production state. Only run them when the user explicitly asks you to. - Deploy: - `fly deploy` / `fly deploy --remote-only` - SSH exec / console: - `fly ssh console -a <app> -C "<command>"` - Secrets changes: - `fly secrets set -a <app> KEY=value` See `references/safety.md`. ## Fly Postgres basics ### Identify the Postgres app - `fly postgres list` ### Attach Postgres to an app - `fly postgres attach <pg-app> -a <app>` ### Create a database inside the cluster - `fly postgres db create <db_name> -a <pg-app>` - `fly postgres db list -a <pg-app>` ### Connect (psql) - `fly postgres connect -a <pg-app>` ## GitHub Actions deploys / previews - For production CD: use Fly’s GitHub Action (`superfly/flyctl-actions/setup-flyctl`) and run `flyctl deploy`. - For PR previews: - Prefer one **preview app per PR** and one **database per PR** inside a shared Fly Postgres cluster. - Automate create/deploy/comment on PR; destroy on close. (See `references/github-actions.md`.) ## Bundled resources - `references/safety.md`: safety rules (read-only by default; ask before mutating state). - `references/rails-docker-builds.md`: Rails/Docker/Fly build failure patterns + fixes. - `references/github-actions.md`: Fly deploy + preview workflows. - `scripts/fly_app_from_toml.sh`: tiny helper to print the Fly app name from fly.toml (shell-only; no ruby).