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miren app run

Open interactive shell in a new sandbox

This command runs a command in a fresh sandbox built from your app's active version — the same image, environment variables, and working directory as your deployed app — and connects your terminal to it.

With no arguments it opens an interactive shell. With arguments it runs that command. With --task it runs a task declared in app.toml.

This is useful for:

  • Debugging application issues in an isolated environment
  • Running one-off commands with your app's configuration
  • Running a declared task by hand, such as re-running a migration without redeploying
  • Exploring the container filesystem

How It Works​

  1. Miren records a run: a durable entity holding what was executed, by whom, and how it ended
  2. The run controller builds a sandbox from your app's active version and starts the command
  3. Your terminal attaches to that command
  4. On exit, the command's exit code is recorded and propagated to your shell, and the sandbox is torn down

Runs outlive your terminal​

Disconnecting is not cancelling. If your connection drops, the command keeps going — reattach with miren app attach, read its output with miren logs run, or leave it and let its timeout reap it.

Press Ctrl-P Ctrl-Q to leave a run you are attached to. It keeps running.

--detach therefore means exactly one thing: don't attach my terminal right now. Use miren app runs cancel to actually stop a run.

Ctrl-C goes to your command

Your keystrokes reach the command, so Ctrl-C interrupts it rather than this CLI — the same as pressing it in a local shell. That is why leaving needs its own sequence.

Sandboxes are per-invocation

The sandbox is per-invocation. Any changes you make (files created, packages installed) are discarded when it ends.

Reaching an existing sandbox

Runs are recorded, so miren app runs shows what has been executed against an app and how it ended. To reach into an already-running production sandbox instead, use miren sandbox exec.

Usage​

miren app run [args...] [flags]

Flags​

  • --detach — Create the run without attaching a terminal
  • --task — Task to run; defaults to the console task

Config Options​

  • --cluster, -C — Cluster name
  • --config — Path to the config file

App Options​

  • --app, -a — Application name
  • --dir, -d — Directory to run from (default: .)

Global Options​

  • --options — Path to file containing options
  • --server-address — Server address to connect to (default: 127.0.0.1:8443)
  • --verbose, -v — Enable verbose output

Examples​

Open a shell in your app's environment:

miren app run

Run a specific command:

miren app run -- bin/rails console

Run database migrations:

miren app run -- bin/rails db:migrate

Run a declared task:

miren app run --task reindex

Start a task without holding a terminal:

miren app run --task reindex --detach

See also​