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print

The print function writes its arguments as one line to the script's standard output. Use it for the data a script produces. Standard output is also the step value when the script does not assign output.

Usage​

print(*args, sep = " ")

Arguments​

*args

(Optional) Any number of values. Strings are written as they are. Other values are written in their display form, such as True, None, [1, "x"], or {"k": "v"}.

sep
(Optional) Keyword-only. The text placed between values. Defaults to a single space.

Returns​

The return value is None.

Behavior​

  • Each call writes one line, ending with a newline. A call with no arguments writes an empty line.
  • The line goes to the script's stdout channel, subject to the step's output settings and secret masking. For a standalone script, that is the program's standard output.
  • When a step does not assign output, everything the script printed becomes the step value, including the trailing newline.
  • Inside steps.parallel tasks, each line is written whole and prefixed with the task name, such as [dev] . Lines from different tasks can arrive in any order but never interleave within a line. A group with a single task writes without a prefix.

Status messages for people belong on stderr: use ui.info, ui.success, and ui.warning. Diagnostics for troubleshooting belong in the log: use log.info and its siblings.

FunctionChannelBecomes the step value
printstdoutYes, when output is unset
ui.info, ui.success, ui.warningstderrNo
log.trace through log.errorThe Atmos log, at the configured levelNo

Examples​

Print several values​

print("a", 1, True, None, [1, "x"], {"k": "v"})
print("a", "b", "c", sep = ", ")
print("no separator", sep = "")
print()
a 1 True None [1, "x"] {"k": "v"}
a, b, c
no separator

Use printed text as the step value​

steps:
  - name: calc
    type: script
    interpreter: starlark
    script: |
      print("only stdout")
  - name: show
    type: shell
    command: echo 'value={{ .steps.calc.value }}'
only stdout
value=only stdout

Print from parallel tasks​

def one(n):
    print("task", n)

steps.parallel(tasks = [steps.task(str(n), one, args = [n]) for n in [1, 2]])
[1] task 1
[2] task 2

The two lines can appear in either order.

Related​