Basic Usage

myna is built around the concept of Actions. An action is a simple TOML file that describes an AWS operation, like invoking a Lambda function or sending an SQS message.

The run Command

The primary way to use myna is the run command. It executes a single action file.

Your First Action File

Actions are defined in TOML files. Here is a simple example of an action that invokes a Lambda function with a JSON payload:

my-action.toml

version = "1.0"
kind = "lambda.invoke"
description = "Invoke a simple JSON handler"

[lambda]
function_name = "my-lambda-function"

[pre]
user_id = "user_123"

[payload]
data = """
{
  "user_id": "{{user_id}}",
  "status": "active"
}
"""

Simple Execution

To run the action defined above:

myna run ./my-action.toml

Execution Contexts

myna automatically detects the context in which an action is being run.

1. Standalone Context

If you run an action file that is not part of a collection, myna runs it with only the variables defined inside that file. This is perfect for quick tests.

2. Collection Context

If myna finds a myna.toml file in the current directory or any parent directory, it treats the action as part of a Collection. This allows you to:

• Share variables across multiple actions.
• Use environment-specific configurations.

Using Environments

When working within a collection, you can switch between different environments (like dev or prod) using the --env flag:

myna run ./actions/invoke-lambda.toml --env dev

This will load variables from environments/dev.toml relative to your collection root.

Variable Resolution

myna resolves variables in a specific order of priority:

1. Action Variables: Defined in the [pre] block of your action TOML. (Highest priority)
2. Collection Variables: Defined in myna.toml.
3. Environment Variables: Defined in files like environments/dev.toml. (Lowest priority)

This hierarchy allows you to define defaults at the collection level and override them for specific actions or environments.

Next Steps

• Explore Design Overview to learn more about the project structure.
• Check out the Action Guide to learn more about configuring actions.