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chromium_depot_tools/ninjalog.README.md
Takuto Ikuta 540ba9dde0 [ninjalog] add ninjalog.README.md
I added document explaining ninjalog collection.
This document explains what type of data is collected and how the data will be used.

Bug: 900161, b/120645342
Change-Id: If47517aaa7a5510e4a634b5ccc0e4127d014dcb9
Reviewed-on: https://chromium-review.googlesource.com/c/1381912
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
2018-12-19 22:24:08 +00:00

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1.9 KiB
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# Ninja build log collection
[TOC]
## Overview
When chromium developers use autoninja for their build,
e.g.
```
$ autoninja -C out/Release chrome
```
autoninja uploads ninja's build log for Google employees but we don't collect
logs from external contributors.
We use [this page](https://chromium-build-stats-staging.appspot.com/should-upload)
to decide whether an autoninja user is a Googler or not. Only people with access
to Google's internal network can see 'Success'.
Before uploading logs, autoninja shows a message 10 times to warn users that we
will collect build logs.
autoninja users can also opt in or out by using the following commands:
* `ninjalog_uploader_wrapper.py opt-in`
* `ninjalog_uploader_wrapper.py opt-out`
## What type of data are collected?
The collected build log contains
* output file of build tasks (e.g. chrome, obj/url/url/url_util.o)
* hash of build command
* start and end time of build tasks
See [manual of ninja](https://ninja-build.org/manual.html#ref_log) for more
details.
In addition to ninja's build log, we send the following data for further
analysis:
* OS (e.g. Win, Mac or Linux)
* number of cpu cores of building machine
* build targets (e.g. chrome, browser_tests)
* parallelism passed by -j flag
* following build configs
* host\_os, host\_cpu
* target\_os, target\_cpu
* symbol\_level
* use\_goma
* is\_debug
* is\_component\_build
We don't collect personally identifiable information
(e.g. username, ip address).
## Why ninja log is collected? / How the collected logs are used?
We (goma team) collect build logs to find slow build tasks that harm developer's
productivity. Based on collected stats, we find the place/build tasks where we
need to focus on. Also we use collected stats to track chrome build performance
on developer's machine. We'll use this stats to measure how much we can/can't
improve build performance on developer's machine.