fix/weekly cache metrics endpoint

[alanpeixinho]

What it is

Makes the metrics page cache its response for a week, so we can:

1. Keep parity with email
2. Avoid slow endpoint calls

How to test:

Test warming cache crontab

1. First install the crontabs via poetry run python3 manage.py crontab add
2. Make sure they are installed poetry run python3 manage.py crontab show
3. You can execute the crontab via poetry run python3 manage.py crontab run <hash of cronjob>
   * It is important to point here that the warm is supposed to run at the same time as email metrics (saturday), so they might not be aligned to the same days as frontend requests.
   * Alternatively to this, we could change the system clock.
4. Verify the function that queries and stores on redis runs properly.
5. Verify redis now has updated cache on the keys (metricsTotalObjects, metricsBuildIncidents, metricsNewBuildIncidents, metricsLabSummary) (via redis-cli) or via python script.
6. Remember to remove the crontab from your system poetry run python3 manage.py crontab remove

Testing endpoint

1. Go to the metrics page
2. Make sure it loads data from the range [lastSaturday - 7 days, lastSaturday] for the "previous week" and [lastSaturday - 14, lastSaturday] for the "2 previous weeks".
3. Make sure subsequent access are cached.

Closes #1940

• feat: add checkout selectors on hardware page (feat: add checkout selectors on hardware page #1904)
• feat: dynamic metrics page (feat: dynamic metrics page #1920)
• refactor: unversion tree and hardware listing flows (refactor: Unversion pages/endpoints for tree/hardware listing #1923)
• feat: increase metrics cache time (feat: increase metrics cache time #1934)
• Add githooks to manage commit DCO sign-off (Add githooks to manage commit DCO sign-off #1932)
• Reports regzbot tracking (Reports regzbot tracking #1925)
• fix: Include aggregate tables on snapshot/restore update_db commands (fix: Include aggregate tables on snapshot/restore update_db commands #1936)
• fix(metrics): stabilize query cache and add weekly warm cron

[bhcopeland]

Trying to work out the SQL below, I think this will be an 8-day window? Because it causes SQL to be at the end of the 7-day window (i.e. on the last day it will be at midnight).

[alanpeixinho]

yes, you are correct.
The cached query is happening at the start of the day (just like the mail notification), so the 8th day would end up empty.
But still, it is not robust to rely on time of the call.