ctx

The ctx value describes the situation a script runs in: its raw arguments, its source file, the parsed inputs of a custom command, the component in scope, and the lifecycle hook that triggered it. Every attribute is read-only.

Usage

ctx.args         # list of script arguments
ctx.script       # source file, or None
ctx.flags        # dictionary of parsed flags
ctx.arguments    # dictionary of parsed named arguments
ctx.component    # component handle, or None
ctx.hook         # hook details, or None
ctx.operation    # parent operation details, or None

Attributes

ctx.args

The command-line arguments passed to a standalone script.

ctx.script

The path and directory of the script file, when the script was read from a file.

ctx.flags

The parsed flags of a custom command, or the flags a workflow supplies.

ctx.arguments

The parsed named arguments of a custom command.

ctx.component

The component a custom command or hook is scoped to.

ctx.hook

The name and event of the lifecycle hook that runs the script.

ctx.operation

The parent operation, such as terraform apply, and its outcome.

What each entry point provides

The attributes always exist. What they hold depends on how the script started:

Entry point	ctx.args	ctx.script	ctx.flags	ctx.arguments	ctx.component	ctx.hook, ctx.operation
Standalone script	Arguments after the script name or stdin marker (-)	The script file, or None for stdin	Empty	Empty	None	None
Custom command	Empty	Set when the script comes from a local !include	Parsed flags	Parsed arguments	The command's component when it declares component:, otherwise None	None
Workflow step	Empty	Set when the script comes from a local !include	Workflow flags, as strings	Empty	None	None
Lifecycle hook	Empty	Set when the script comes from a local !include	Empty	Empty	The hook's component, or None for an aggregate hook	The hook and the parent operation

Steps inside parallel and matrix groups inherit the context of the step that contains them. A standalone program that declares its interface with cli.command receives its parsed inputs as the arguments of its entry function instead of through ctx.flags and ctx.arguments.

Examples

Branch on the entry point

if ctx.hook != None:
    print("running as the {} hook".format(ctx.hook.event))
elif len(ctx.args) > 0:
    print("standalone script with arguments:", ctx.args)
else:
    print("workflow or custom command step")

Read inputs in a custom command

replicas = int(ctx.flags["replicas"])
service = ctx.arguments["service"]
print("{}: {} replicas".format(service, replicas))

Related

• env holds the step's declared environment inputs.
• cli.command declares a standalone program's interface.
• Atmos Automation Language and the script step