79 lines
4.9 KiB
Markdown
79 lines
4.9 KiB
Markdown
---
|
|
permalink: "/{{ year }}/{{ month }}/{{ day }}/boring-monitoring"
|
|
title: "This Week in Glean: Boring Monitoring"
|
|
published_date: "2021-02-24 15:00:00 +0100"
|
|
layout: post.liquid
|
|
data:
|
|
route: blog
|
|
tags:
|
|
- mozilla
|
|
---
|
|
|
|
(“This Week in Glean” is a series of blog posts that the Glean Team at Mozilla is using to try to communicate better about our work. They could be release notes, documentation, hopes, dreams, or whatever: so long as it is inspired by Glean.)
|
|
|
|
All "This Week in Glean" blog posts are listed in the [TWiG index](https://mozilla.github.io/glean/book/appendix/twig.html)
|
|
(and on the [Mozilla Data blog](https://blog.mozilla.org/data/category/glean/)).
|
|
This article is [cross-posted on the Mozilla Data blog](https://blog.mozilla.org/data/2021/02/24/this-week-in-glean-boring-monitoring/).
|
|
|
|
---
|
|
|
|
Every Monday the Glean has its weekly Glean SDK meeting.
|
|
This meeting is used for 2 main parts:
|
|
First discussing the features and bugs the team is currently investigating or that were requested by outside stakeholders.
|
|
And second bug triage & monitoring of data that Glean reports in the wild.
|
|
|
|
Most of the time looking at our monitoring is boring and that's a good thing.
|
|
|
|
From the beginning the Glean SDK supported extensive [error reporting] on data collected by the framework inside end-user applications.
|
|
Errors are produced when the application tries to record invalid values.
|
|
That could be a negative value for a counter that should only ever go up or stopping a timer that was never started.
|
|
Sometimes this comes down to a simple bug in the code logic and should be fixed in the implementation.
|
|
But often this is due to unexpected and surprising behavior of the application the developers definitely didn't think about.
|
|
Do you know all the ways that your Android application can be started?
|
|
There's a whole lot of events that can launch it, even in the background, and you might miss instrumenting all the right parts sometimes.
|
|
Of course this should then also be fixed in the implementation.
|
|
|
|
## Monitoring Firefox for Android
|
|
|
|
For our weekly monitoring we look at one application in particular: [Firefox for Android][fenix].
|
|
Because errors are reported in the same way as other metrics we are able to query our database, aggregate the data by specific metrics and errors, generate graphs from it
|
|
and create dashboards on our instance of [Redash].
|
|
|
|
|
|
|
|
The above graph displays error counts for different metrics. Each line is a specific metric and error (such as `Invalid Value` or `Invalid State`).
|
|
The exact numbers are not important.
|
|
What we're interested in is the general trend.
|
|
Are the errors per metrics stable or are there sudden jumps?
|
|
Upward jumps indicate a problem, downward jumps probably means the underlying bug got fixed and is finally rolled out in an update to users.
|
|
|
|
|
|
|
|
We have another graph that doesn't take the raw number of errors, but averages it across the entire population.
|
|
A sharp increase in error counts sometimes comes from a small number of clients, whereas the errors for others stay at the same low-level.
|
|
That's still a concern for us, but knowing that a potential bug is limited to a small number of clients may help with finding and fixing it.
|
|
And sometimes it's really just bogus client data we get and can dismiss fully.
|
|
|
|
Most of the time these graphs stay rather flat and boring and we can quickly continue with other work.
|
|
Sometimes though we can catch potential issues in the first days after a rollout.
|
|
|
|
|
|
|
|
In this graph from the nightly release of Firefox for Android two metrics started reporting a number of errors that's far above any other error we see.
|
|
We can then quickly find the implementation of these metrics and report that to the responsible team ([Filed bug][fenix-bug], and the [remediation PR][fenix-pr]).
|
|
|
|
## But can't that be automated?
|
|
|
|
It probably can!
|
|
But it requires more work than throwing together a dashboard with graphs.
|
|
It's also not as easy to define thresholds on these changes and when to report them.
|
|
There's work underway that hopefully enables us to more quickly build up these dashboards for any product using the Glean SDK,
|
|
which we can then also extend to do more reporting automated.
|
|
The final goal should be that the product teams themselves are responsible for monitoring their data.
|
|
|
|
[error reporting]: https://mozilla.github.io/glean/book/user/error-reporting.html
|
|
[fenix]: https://github.com/mozilla-mobile/fenix/
|
|
[Redash]: https://redash.io/
|
|
[fenix-bug]: https://github.com/mozilla-mobile/fenix/issues/18114
|
|
[fenix-pr]: https://github.com/mozilla-mobile/fenix/pull/18115
|