At https://github.com/n8n-io/n8n/pull/8213 we introduced Redis hashes
for workflow ownership and manual webhooks...
- to remove clutter from multiple related keys at the top level,
- to improve performance by preventing serializing-deserializing, and
- to guarantee atomicity during concurrent updates in multi-main setup.
Workflow activation errors can also benefit from this. Added test
coverage as well.
To test manually, create a workflow with a trigger with an invalid
credential, edit the workflow's `active` column to `true`, and restart.
The activation error should show as a red triangle on canvas and in the
workflow list.
Story: https://linear.app/n8n/issue/PAY-1188
- Implement Redis hashes on the caching service, based on Micha's work
in #7747, adapted from `node-cache-manager-ioredis-yet`. Optimize
workflow ownership lookups and manual webhook lookups with Redis hashes.
- Simplify the caching service by removing all currently unused methods
and options: `enable`, `disable`, `getCache`, `keys`, `keyValues`,
`refreshFunctionEach`, `refreshFunctionMany`, `refreshTtl`, etc.
- Remove the flag `N8N_CACHE_ENABLED`. Currently some features on
`master` are broken with caching disabled, and test webhooks now rely
entirely on caching, for multi-main setup support. We originally
introduced this flag to protect against excessive memory usage, but
total cache usage is low enough that we decided to drop this setting.
Apparently this flag was also never documented.
- Overall caching service refactor: use generics, reduce branching, add
discriminants for cache kinds for better type safety, type caching
events, improve readability, remove outdated docs, etc. Also refactor
and expand caching service tests.
Follow-up to: https://github.com/n8n-io/n8n/pull/8176
---------
Co-authored-by: Michael Auerswald <michael.auerswald@gmail.com>
Followup to #7566 | Story: https://linear.app/n8n/issue/PAY-926
### Manual workflow activation and deactivation
In a multi-main scenario, if the user manually activates or deactivates
a workflow, the process (whether leader or follower) that handles the
PATCH request and updates its internal state should send a message into
the command channel, so that all other main processes update their
internal state accordingly:
- Add to `ActiveWorkflows` if activating
- Remove from `ActiveWorkflows` if deactivating
- Remove and re-add to `ActiveWorkflows` if the update did not change
activation status.
After updating their internal state, if activating or deactivating, the
recipient main processes should push a message to all connected
frontends so that these can update their stores and so reflect the value
in the UI.
### Workflow activation errors
On failure to activate a workflow, the main instance should record the
error in Redis - main instances should always pull activation errors
from Redis in a multi-main scenario.
### Leadership change
On leadership change...
- The old leader should stop pruning and the new leader should start
pruning.
- The old leader should remove trigger- and poller-based workflows and
the new leader should add them.
