`Collect()` is called whenever the `/metrics` endpoint is hit to
retrieve metrics.
The queries used in prebuilds metrics collection are quite heavy, and we
want to avoid having them running concurrently / too often to keep db
load down.
Here I'm moving towards a background retrieval of the state required to
set the metrics, which gets invalidated every interval.
Also introduces `coderd_prebuilt_workspaces_metrics_last_updated` which
operators can use to determine when these metrics go stale.
See https://github.com/coder/coder/pull/17789 as well.
---------
Signed-off-by: Danny Kopping <dannykopping@gmail.com>
Database transactions hold onto connections, and `pubsub.Publish` tries
to acquire a connection of its own. If the latter is called within a
transaction, this can lead to connection exhaustion.
I plan two follow-ups to this PR:
1. Make connection counts tuneable
https://github.com/coder/coder/blob/main/cli/server.go#L2360-L2376
We will then be able to write tests showing how connection exhaustion
occurs.
2. Write a linter/ruleguard to prevent `pubsub.Publish` from being
called within a transaction.
---------
Signed-off-by: Danny Kopping <dannykopping@gmail.com>
Don't specify the template version for a delete transition, because the
prebuilt workspace may have been created using an older template
version.
If the template version isn't explicitly set, the builder will
automatically use the version from the last workspace build - which is
the desired behavior.
Closes https://github.com/coder/internal/issues/510
<details>
<summary> Refactoring Summary </summary>
### 1) `CalculateActions` Function
#### Issues Before Refactoring:
- Large function (~150 lines), making it difficult to read and maintain.
- The control flow is hard to follow due to complex conditional logic.
- The `ReconciliationActions` struct was partially initialized early,
then mutated in multiple places, making the flow error-prone.
Original source:
fe60b569ad/coderd/prebuilds/state.go (L13-L167)
#### Improvements After Refactoring:
- Simplified and broken down into smaller, focused helper methods.
- The flow of the function is now more linear and easier to understand.
- Struct initialization is cleaner, avoiding partial and incremental
mutations.
Refactored function:
eeb0407d78/coderd/prebuilds/state.go (L67-L84)
---
### 2) `ReconciliationActions` Struct
#### Issues Before Refactoring:
- The struct mixed both actionable decisions and diagnostic state, which
blurred its purpose.
- It was unclear which fields were necessary for reconciliation logic,
and which were purely for logging/observability.
#### Improvements After Refactoring:
- Split into two clear, purpose-specific structs:
- **`ReconciliationActions`** — defines the intended reconciliation
action.
- **`ReconciliationState`** — captures runtime state and metadata,
primarily for logging and diagnostics.
Original struct:
fe60b569ad/coderd/prebuilds/reconcile.go (L29-L41)
</details>
---------
Signed-off-by: Danny Kopping <dannykopping@gmail.com>
Co-authored-by: Sas Swart <sas.swart.cdk@gmail.com>
Co-authored-by: Danny Kopping <dannykopping@gmail.com>
Co-authored-by: Dean Sheather <dean@deansheather.com>
Co-authored-by: Spike Curtis <spike@coder.com>
Co-authored-by: Danny Kopping <danny@coder.com>
