I've been working from home either partially or fully in the last few decades. So here are the most important tips/adjustments that will help you adjust quickly:
How do I avoid cold starts? Why do I see function calls to my lambda when nobody accessed it? What is keep_warm in zappa? How much does it cost me?
Cold starts happen when your function hasn't been used for a while (the time is defined by AWS and, from …
read moreWhen I published Lambda that is called regularly like a cron task someone asked me how much would it cost (a fair question taking into account you pay per use, not per infrastructure). With lambda you pay for two things: a request/invocation and the time times memory used.
For …
read moreDo you want to run a task/function regularly, but don't want to pay an EC2 instance just to run cron? Or don't want to set it up and manage the instance?
You can use AWS lambdas (and zappa) for that. As an example, let's create and deploy a function …
read moreStuck with zappa? Assuming you're looking for help about the python lambda library and not the singer, then the following should help.
The main documentation is the project's README: https://github.com/Miserlou/Zappa/blob/master/README.md - check the links section for particular integrations (ex: django, flask, alexa skills …
read moreAre you running your development environment with different packages than production? And your tests? Or even different parts of production?
The common advice (example) is to pin versions of packages in a requirements.txt file (that means defining which particular version works for your program). That advice fails because the …
read moreOn the previous article Your queries are slow, but memory/cpu usage is low I mentioned that one of the reasons where you can observe slowness in an app on AWS that is using RDS is IOPS budgeting. The main symptom you've already gathered from the title and that's why …
read moreRecently I changed a function to receive a single argument instead of the previous two. Unfortunately that resulted in another function failing later. The issue wasn't lack of tests (that function had 100% coverage), but the way this function was tested.
@patch('module.function_changed')
def test_that_function_was_called(mock_function):
task()
mock_function.assert_called_with …You're noticing timeouts on queries running on your PostgreSQL database? Or just slower response to queries? And when you look at RDS monitoring the cpu and memory look like the machine is doing nothing?
There are two main causes I've found for this: lock contention and IOPS limits. Today I'm …
read moreWant to know when something goes wrong in a lambda? Tired of replicating all your alarm setup for each lambda?
If you just want a simple setup on each lambda that guarantees that you get alerts with enough information to be actionable, zappa-sentry is for you.
You'll need a sentry …
read moreYou did a zappa deploy and it failed with An error occurred (ValidationException) when calling the PutRule operation: Provided role <your lambda role> cannot be assumed by principal 'events.amazonaws.com'?
You tried to create a lambda with a new handmade role only to be greeted by this …
read moreYou did a zappa deploy and it failed with InvalidParameterValueException: An error occurred (InvalidParameterValueException) when calling the CreateFunction operation: The role defined for the function cannot be assumed by Lambda?
You tried to create a lambda with a new handmade role only to be greeted by this cryptic error message …
read moreLooking to delete old entries from a table because they've expired? Want to do it in an elegant way?
I usually like to split this kind of functionality into two different parts: the method that does the deleting and a static method that can be invoked from cron, a celery …
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