Docs: Metrics - Assert multiple EMF blobs with pytest has invalid python syntax

[michaelbrewer]

Expected Behaviour

Metrics - Assert multiple EMF blobs with pytest example should be valid python syntax

Current Behaviour

Current example has a python syntax error of ',' or ')' expected

Code snippet

from aws_lambda_powertools import Metrics
from aws_lambda_powertools.metrics import MetricUnit

from collections import namedtuple

import json

def capture_metrics_output_multiple_emf_objects(capsys):
    return [json.loads(line.strip()) for line in capsys.readouterr().out.split("\n") if line]

def test_log_metrics(capsys):
    # GIVEN Metrics is initialized
    metrics = Metrics(namespace="ServerlessAirline")

    # WHEN log_metrics is used with capture_cold_start_metric
    @metrics.log_metrics(capture_cold_start_metric=True)
    def lambda_handler(evt, ctx):
        metrics.add_metric(name="SuccessfulBooking", unit=MetricUnit.Count, value=1)
        metrics.add_dimension(name="environment", value="prod")

    # log_metrics uses function_name property from context to add as a dimension for cold start metric
    LambdaContext = namedtuple("LambdaContext", "function_name")
    lambda_handler({}, LambdaContext("example_fn")

    cold_start_blob, custom_metrics_blob = capture_metrics_output_multiple_emf_objects(capsys)

    # THEN ColdStart metric and function_name dimension should be logged
    # in a separate EMF blob than the application metrics
    assert cold_start_blob["ColdStart"] == [1.0]
    assert cold_start_blob["function_name"] == "example_fn"

    assert "SuccessfulBooking" in custom_metrics_blob  # as per previous example

Possible Solution

Fix the python syntax, like in PR #1122, deployed at https://gyft.github.io/aws-lambda-powertools-python/latest/core/metrics/#functional-testing

import json
from collections import namedtuple

from aws_lambda_powertools import Metrics
from aws_lambda_powertools.metrics import MetricUnit


def capture_metrics_output_multiple_emf_objects(capsys):
    return [json.loads(line.strip()) for line in capsys.readouterr().out.split("\n") if line]


def test_log_metrics(capsys):
    # GIVEN Metrics is initialized
    metrics = Metrics(namespace="ServerlessAirline")

    # WHEN log_metrics is used with capture_cold_start_metric
    @metrics.log_metrics(capture_cold_start_metric=True)
    def lambda_handler(evt, ctx):
        metrics.add_metric(name="SuccessfulBooking", unit=MetricUnit.Count, value=1)
        metrics.add_dimension(name="environment", value="prod")

    # log_metrics uses function_name property from context to add as a dimension for cold start metric
    LambdaContext = namedtuple("LambdaContext", "function_name")
    lambda_handler({}, LambdaContext("example_fn"))

    cold_start_blob, custom_metrics_blob = capture_metrics_output_multiple_emf_objects(capsys)

    # THEN ColdStart metric and function_name dimension should be logged
    # in a separate EMF blob than the application metrics
    assert cold_start_blob["ColdStart"] == [1.0]
    assert cold_start_blob["function_name"] == "example_fn"

    assert "SuccessfulBooking" in custom_metrics_blob  # as per previous example

Steps to Reproduce

1. Go to https://awslabs.github.io/aws-lambda-powertools-python/latest/core/metrics/#functional-testing
2. Copy code for Assert multiple EMF blobs with pytest
3. Try to compile the python file

AWS Lambda Powertools for Python version

latest

AWS Lambda function runtime

3.9

Packaging format used

PyPi

Debugging logs

N/A

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