feat(parameters): Add force_fetch option

[michaelbrewer]

Issue #, if available:

#131

Description of changes:

Changes:

• Add new force_fetch to always fetch the latest value, even if there is a cached value

Example based on https://github.com/alexcasalboni/ssm-cache-python#complex-invalidation-based-on-signals

import os
from aws_lambda_powertools.utilities import parameters


class InvalidCredentials(Exception):
    """Raised when client get an invalid credentials error"""


class Client:
    password = None

    def configure(self, password):
        self.password = password

    def read_record(self):
        """Might raise an InvalidCredentials exception """


DB_PASS_PARAM = os.environ["DB_PASS_PARAM"]
db_client = Client()
db_client.configure(parameters.get_parameter(DB_PASS_PARAM))


def refresh_db_password():
    db_client.configure(parameters.get_parameter(DB_PASS_PARAM, force_fetch=True))


def read_record(is_retry=False):
    try:
        return db_client.read_record()
    except InvalidCredentials:
        if not is_retry:  # avoid infinite recursion
            refresh_db_password()  # force parameter refresh
            return read_record(is_retry=True)


def handler(event, context):
    return {"record": read_record()}

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-io]

Codecov Report

Merging #341 (02d3957) into develop (5daa45a) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #341   +/-   ##
========================================
  Coverage    99.88%   99.88%           
========================================
  Files           94       94           
  Lines         3521     3521           
  Branches       172      172           
========================================
  Hits          3517     3517           
  Misses           2        2           
  Partials         2        2           

Impacted Files	Coverage Δ
aws_lambda_powertools/utilities/parameters/base.py	100.00% <100.00%> (ø)
aws_lambda_powertools/utilities/parameters/ssm.py	100.00% <100.00%> (ø)

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[michaelbrewer]

@heitorlessa I added a force_update option but i did notice that the sdk_options is confusing things for PyCharm

[michaelbrewer]

@heitorlessa I made it an explicit option throughout, the question is what should it be called?

force_update, refresh, force_fetch ?

[heitorlessa]

For completion, as @nmoutschen suggested, let's go with force_fetch as that doesn't make assumption whether we have something cache to be ignored.

[michaelbrewer]

For completion, as @nmoutschen suggested, let's go with force_fetch as that doesn't make assumption whether we have something cache to be ignored.

Ok @nmoutschen @heitorlessa i have made the update to force_fetch