pypyraws.steps.waitfor permalink

custom waiter for aws state changes permalink

Custom waiter for any aws client operation. Where pypyraws.steps.wait uses the official AWS waiters from the low-level client api, this step allows you to execute any aws low-level client method and wait for a specified field in the response to become the value you want it to be.

AWS does not have waiters for all state changes. Use this to create your own waiter for any property state change.

This is especially handy for things like Beanstalk, because Elastic Beanstalk does not have Waiters for environment creation.

input permalink

The input context looks like this:

  awsClientIn: # required. awsClientIn allows the same arguments as pypyraws.steps.client.
    serviceName: elasticbeanstalk
    methodName: describe_environments
        ApplicationName: my wonderful beanstalk default application
          - my-wonderful-environment
        VersionLabel: v0.1
  waitForField: '{Environments[0][Status]}' # required. format expression for field name to check in awsClient response
  toBe: Ready # required. Stop waiting when waitForField equals this value
  pollInterval: 30 # optional. Seconds to wait between polling attempts. Defaults to 30 if not specified.
  maxAttempts: 10 # optional. Defaults to 10 if not specified.
  errorOnWaitTimeout: True # optional. Defaults to True if not specified. Stop processing if maxAttempts exhausted without reaching toBe value.

See pypyraws.steps.client for a full listing of available arguments under awsClientIn.

If errorOnWaitTimeout is True and max_attempts exhaust before reaching the desired target state, pypyr will stop processing with a pypyraws.errors.WaitTimeOut error.

The awsWaitFor context supports text {substitution} formatting expressions.

Do note that while waitForField uses substitution style format strings, the substitutions are made against the response object that returns from the aws client call specified in awsClientIn, and not from the pypyr context itself.

output permalink

Once this step completes it adds awsWaitForTimedOut to the pypyr context. This is a boolean value with values:

TrueerrorOnWaitTimeout=False and max_attempts exhausted without reaching toBe.
FalsewaitForField's value becomes toBe within max_attempts.

example permalink

See a worked example for an elastic beanstalk custom waiter for environmment creation here.

last updated on .