Gold Production Manual

First make sure you are familiar with the design of gold by reading the architectural overview doc.

Clients can file a bug against Gold at go/gold-bug.

General Metrics

The following dashboard is for the skia-public instances:

The following dashboard is for the skia-corp instances:

Some things to look for:

  • Do goroutines or memory increase continuously (e.g leaks)?
  • How fresh is the tile data? (this could indicate something is stuck).
  • How is ingestion liveness? Anything stuck?


To investigate the load of Gold's RPCs navigate to and try doing the search:


You can use the func timers to even search by package, e.g. finding QPS of all Firestore related functions:


If you find something problematic, then timer_func_timer_ns{appgroup=~"gold.+"}/1000000000 is how to see how many milliseconds a given timer actually took.

General Logs

Logs for Gold instances in skia-public/skia-corp are in the usual GKE container grouping, for example:


Items below here should include target links from alerts.


Gold has a pubsub subscription for events created in its bucket. This alert means we haven‘t successfully ingested a file in over 24 hours. This could mean that ingestion is throwing errors on every file or the repo isn’t very busy.

This has happened before because gitsync stopped, so check that out too.

Key metrics: liveness_gold_bt_s{metric=“last-successful-process”}, liveness_last_successful_git_sync_s


Gold regularly polls its GCS buckets for any files that were not successfully ingested via PubSub event when the file was created (aka “streaming”). This alert means it has been at least 10 minutes since this happened; this should happen every 5 minutes or so, even in not-busy repos.

This has happened before because gitsync stopped, so check that out too.

Key metrics: liveness_gold_bt_s{metric=“since-last-run”}, liveness_last_successful_git_sync_s


This alert means gold was unable to calculate which ignore rules were expired. Search the logs for “ignorestore.go” to get a hint as to why.

This has happened before because of manually-edited (and incorrect) Firestore data so maybe check out the raw data

Key metrics: gold_expired_ignore_rules_monitoring


Too much time has elapsed since Gold noticed a commit. This occasionally is a false positive if a commit simply hasn't landed in the repo we are tracking.

In the past, this has indicated git-sync might have had problems, so check out the logs of the relevant git-sync instance.

Key metrics: gold_last_commit_age_s


Gold has noticed there is a newer commit available for processing, but hasn't succeeded on moving forward.

This would usually indicate an issue with Gold itself, so check the logs of the Gold instance.

Key metrics: gold_last_commit_age_s


The underlying metric here is reset when the frontend status is recomputed. This normally gets recomputed when the Gold sliding window of N commits (aka “tile”) is updated or when expectations are changed (e.g. something gets triaged).

This could fire because of a problem in golden/go/status.go or computing the current tile takes longer than the minimum for the alert.

Key metrics: liveness_gold_status_monitoring_s


The recent rate of errors for ingestion is high, it is typically well below 0.1. See the error logs for the given instance for more.


The recent rate of errors for the diff server is high, it is typically well below 0.1. See the error logs for the given instance for more.


The recent rate of errors for the main gold instance is high, it is typically well below 0.1. See the error logs for the given instance for more.


Currently, our baseline servers use QuerySnapshotIterators when fetching expectations out of Firestore. Those run on goroutines. This alert will be active if any of those sharded iterators are down, thus yielding stale results.

To fix, delete one baseliner pod of the affected instance at a time until all of them have restarted and are healthy.

If this alert fires, it probably means the related logic in fs_expstore needs to be rethought.


This section covers both GoldCorruptTryJobParamMaps and GoldTryJobResultsIncompleteData which are probably both active or both inactive. TryJobResults are stored in firestore in a separate document from the Param maps that store the keys so as to lower request data. However, if somehow data was only partially uploaded or corrupted, there might be TryJobResults that reference Params that don't exist.

If this happens, we might need to re-ingest the TryJob data to re-construct the missing data.


The last 20 commits (100 for Chrome, since their tests are slower) have seen 0 data. This probably means something is wrong with goldctl or whatever means is getting data into gold.

Check out the bucket for the instance to confirm nothing is being uploaded and the logs of the ingester if newer stuff is in the bucket, but hasn‘t been processed already. (If it’s an issue with ingestion, expect other alerts to be firing)

Key metrics: gold_empty_commits_at_head


There are many open CLs that have recently seen data from Gold. Having too many open CLs may cause a higher load on CodeReviewSystems (e.g. Gerrit, GitHub) than usual, as we scan over all of these to see if they are still open. Seeing this alert may indicate issues with marking CLs as closed or some other problem with processing CLs.

Key metrics: gold_num_recent_open_cls


Gold hasn‘t been able to go through all the open CLs that have produced data and decide whether to comment on them or not in a while. The presence of this alert might mean we are seeing errors when talking to Firestore or to the Code Review System (CRS). Check the logs on that pod’s frontend server (skiacorrectness) to see what's up.

This might mean we are doing too much and running out of quota to talk to the CRS. Usually out of quota messages will be in the error messages or the bodies of the failing requests.

Key metrics: liveness_gold_comment_monitoring_s, gold_num_recent_open_cls

rate(firestore_ops_count{app=~“gold.+”}[10m]) > 100

HighFirestoreUsageBurst or HighFirestoreUsageSustainedGold

This type of alert means that Gold is probably using more Firestore quota than expected. In an extreme case, this can exhaust our project‘s entire Firestore quota (it’s shared, unfortunately) causing wider outages.

In addition to the advice of identifying QPS above, it can be helpful to identify which collections are receiving a lot of reads/writes. For this, a query like:

    rate(firestore_ops_count{app=~"gold.+"}[10m]) > 100

can help identify those and possibly narrow in on the cause. rate(gold_rpc_call_counter[1m]) > 1 is also a good query to cross-reference this with.


Gold is seeing over 50 QPS to a specific RPC. As of writing, there are only two RPCs that are not throttled from anonymous traffic, so it is likely one of these. See and for more context on these.

This is potentially problematic in that the excess load could be causing Gold to act slowly or even affect other tenants of the k8s pod. The cause of this load should be identified.