* Alerting: Keep track of individual org migration status
Save migration status per migrated org.
Change the meaning (and key/value) of the org_id=0 entry
to store the current (previous) config value used by alerting.
This is so we can know when to upgrade/downgrade by
comparing with the new config value in
UnifiedAlerting.IsEnabled.
* Alerting: Move migration from background service run to ngalert init
sqlite database write contention between the migration's single transaction and
dashboard provisioning's frequent commits was causing the migration to
fail with SQLITE_BUSY/SQLITE_BUSY_SNAPSHOT on all retries.
This is not a new issue for sqlite+grafana, but the discrepancy between the
length of the transactions was causing it to be very consistent. In addition,
since a failed migration has implications on the assumed correctness of the
alertmanager and alert rule definition state, we cause a server shutdown on
error. This can make e2e tests as well as some high-load provisioned
sqlite installations flaky on startup.
The correct fix for this is better transaction management across various
services and is out of scope for this change as we're primarily interested in
mitigating the current bout of server failures in e2e tests when using sqlite.
This PR replaces the vendored models in the migration with their equivalent ngalert models. It also replaces the raw SQL selects and inserts with service calls.
It also fills in some gaps in the testing suite around:
- Migration of alert rules: verifying that the actual data model (queries, conditions) are correct 9a7cfa9
- Secure settings migration: verifying that secure fields remain encrypted for all available notifiers and certain fields migrate from plain text to encrypted secure settings correctly e7d3993
Replacing the checks for custom dashboard ACLs will be replaced in a separate targeted PR as it will be complex enough alone.
