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Local Dev with Render Workflows – Render Docs

Local Dev with Render Workflows

Run tasks locally for faster development and testing.

You can run workflow on your local machine to iterate on them quickly. The Render CLI supports spinning up a local task server that simulates the entire run execution lifecycle. You can trigger from your application code, or from the CLI itself.

As you iterate on your task definitions, the local task server picks up changes automatically. It also retains in-memory logs and results for each run (these are lost on server shutdown).

Prerequisites

Your development machine must have:

  • The Render CLI version 2.35.0 or later

    Installation instructions

    Use any of the following methods to install the Render CLI or upgrade to the latest version:

    Homebrew installation

    Run the following commands:

    After installation completes, open a new terminal tab and run render with no arguments to confirm.

  • A workflow project repo that defines and registers tasks

Limitations

  • The local task server does not yet support (tasks only).
  • Workflows that build from a Dockerfile do not currently support the local task server.

Starting the task server

From your workflow project repo, run the following command:

Replace <WORKFLOW_START_COMMAND> with the command to start your workflow service, such as:

Command not found?

Your local task server spins up and starts listening on port 8120.

You can specify a different port with the --port option:

Triggering local task runs

In application code

This section assumes you have an existing app that triggers task runs.

If you don't, first get set up with Triggering Runs.

You can configure your locally running apps to point to your local task server when triggering task runs. How you do this depends on whether your app uses the Render SDK or the Render API:

If your app uses the Render SDK (TypeScript or Python) to trigger task runs, set the following environment variable(s) to run tasks against your local task server:

In the Render CLI

  1. With your local task server running, run the following command:

    Don't forget the --local flag! Otherwise, the CLI lists tasks from your deployed workflow services.

    The CLI opens an interactive menu of your locally registered tasks:

    Listing tasks in the Render CLI

  2. Select a task and press Enter, then select the run command.

    The CLI prompts you to provide the task's input arguments as a JSON array:

    Providing input arguments for a task run in the Render CLI

    If your task takes zero arguments, provide an empty list, [].

  3. Provide your desired arguments and press Enter. The CLI kicks off your task with a request to your local task server and begins tailing its logs.

    You can remain in this view to view live logs from your task run.

  4. Press Esc to navigate back up to the list of commands for your task. This time select the runs command.

    The CLI opens an interactive menu of the task's local runs:

    Viewing task runs in the Render CLI

  5. Select a run and press Enter, then select the results command.

    The CLI opens a view of the run's results:

    Viewing task run details in the Render CLI

Local-only considerations

  • Logs and results for local task runs are stored in memory by the local task server.
    • This data is lost when the server shuts down.
    • This data is retained indefinitely as long as the server is running. This can lead to high memory usage over time.
    • If you trigger a high volume of local task runs, we recommend periodically restarting your local task server to free up memory.
  • Identifiers for local tasks and runs are randomly generated IDs.
    • The identifier for a given task differs each time you run the local task server.
    • Local identifiers do not correspond to any values in your deployed workflow services.