---
stage: Enablement
group: Distribution
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type: reference
---

# Finding relevant log entries with a correlation ID

In GitLab 11.6 and later, a unique request tracking ID, known as the "correlation ID" has been
logged by the GitLab instance for most requests. Each individual request to GitLab gets
its own correlation ID, which then gets logged in each GitLab component's logs for that
request. This makes it easier to trace behavior in a
distributed system. Without this ID it can be difficult or
impossible to match correlating log entries.

## Identify the correlation ID for a request

The correlation ID is logged in structured logs under the key `correlation_id`
and in all response headers GitLab sends under the header `x-request-id`.
You can find your correlation ID by searching in either place.

### Getting the correlation ID in your browser

You can use your browser's developer tools to monitor and inspect network
activity with the site that you're visiting. See the links below for network monitoring
documentation for some popular browsers.

- [Network Monitor - Firefox Developer Tools](https://developer.mozilla.org/en-US/docs/Tools/Network_Monitor)
- [Inspect Network Activity In Chrome DevTools](https://developers.google.com/web/tools/chrome-devtools/network/)
- [Safari Web Development Tools](https://developer.apple.com/safari/tools/)
- [Microsoft Edge Network panel](https://docs.microsoft.com/en-us/microsoft-edge/devtools-guide-chromium/network/)

To locate a relevant request and view its correlation ID:

1. Enable persistent logging in your network monitor. Some actions in GitLab will redirect you quickly after you submit a form, so this will help capture all relevant activity.
1. To help isolate the requests you are looking for, you can filter for `document` requests.
1. Click the request of interest to view further detail.
1. Go to the **Headers** section and look for **Response Headers**. There you should find an `x-request-id` header with a
value that was randomly generated by GitLab for the request.

See the following example:

![Firefox's network monitor showing an request ID header](img/network_monitor_xid.png)

### Getting the correlation ID from your logs

Another approach to finding the correct correlation ID is to search or watch
your logs and find the `correlation_id` value for the log entry that you're
watching for.

For example, let's say that you want learn what's happening or breaking when
you reproduce an action in GitLab. You could tail the GitLab logs, filtering
to requests by your user, and then watch the requests until you see what you're
interested in.

### Getting the correlation ID from curl

If you're using `curl` then you can use the verbose option to show request and response headers, as well as other debug information.

```shell
➜  ~ curl --verbose "https://gitlab.example.com/api/v4/projects"
# look for a line that looks like this
< x-request-id: 4rAMkV3gof4
```

#### Using jq

This example uses [jq](https://stedolan.github.io/jq/) to filter results and
display values we most likely care about.

```shell
sudo gitlab-ctl tail gitlab-rails/production_json.log | jq 'select(.username == "bob") | "User: \(.username), \(.method) \(.path), \(.controller)#\(.action), ID: \(.correlation_id)"'
```

```plaintext
"User: bob, GET /root/linux, ProjectsController#show, ID: U7k7fh6NpW3"
"User: bob, GET /root/linux/commits/master/signatures, Projects::CommitsController#signatures, ID: XPIHpctzEg1"
"User: bob, GET /root/linux/blob/master/README, Projects::BlobController#show, ID: LOt9hgi1TV4"
```

#### Using grep

This example uses only `grep` and `tr`, which are more likely to be installed than `jq`.

```shell
sudo gitlab-ctl tail gitlab-rails/production_json.log | grep '"username":"bob"' | tr ',' '\n' | egrep 'method|path|correlation_id'
```

```plaintext
{"method":"GET"
"path":"/root/linux"
"username":"bob"
"correlation_id":"U7k7fh6NpW3"}
{"method":"GET"
"path":"/root/linux/commits/master/signatures"
"username":"bob"
"correlation_id":"XPIHpctzEg1"}
{"method":"GET"
"path":"/root/linux/blob/master/README"
"username":"bob"
"correlation_id":"LOt9hgi1TV4"}
```

## Searching your logs for the correlation ID

Once you have the correlation ID you can start searching for relevant log
entries. You can filter the lines by the correlation ID itself.
Combining a `find` and `grep` should be sufficient to find the entries you are looking for.

```shell
# find <gitlab log directory> -type f -mtime -0 exec grep '<correlation ID>' '{}' '+'
find /var/log/gitlab -type f -mtime 0 -exec grep 'LOt9hgi1TV4' '{}' '+'
```

```plaintext
/var/log/gitlab/gitlab-workhorse/current:{"correlation_id":"LOt9hgi1TV4","duration_ms":2478,"host":"gitlab.domain.tld","level":"info","method":"GET","msg":"access","proto":"HTTP/1.1","referrer":"https://gitlab.domain.tld/root/linux","remote_addr":"68.0.116.160:0","remote_ip":"[filtered]","status":200,"system":"http","time":"2019-09-17T22:17:19Z","uri":"/root/linux/blob/master/README?format=json\u0026viewer=rich","user_agent":"Mozilla/5.0 (Mac) Gecko Firefox/69.0","written_bytes":1743}
/var/log/gitlab/gitaly/current:{"correlation_id":"LOt9hgi1TV4","grpc.code":"OK","grpc.meta.auth_version":"v2","grpc.meta.client_name":"gitlab-web","grpc.method":"FindCommits","grpc.request.deadline":"2019-09-17T22:17:47Z","grpc.request.fullMethod":"/gitaly.CommitService/FindCommits","grpc.request.glProjectPath":"root/linux","grpc.request.glRepository":"project-1","grpc.request.repoPath":"@hashed/6b/86/6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b.git","grpc.request.repoStorage":"default","grpc.request.topLevelGroup":"@hashed","grpc.service":"gitaly.CommitService","grpc.start_time":"2019-09-17T22:17:17Z","grpc.time_ms":2319.161,"level":"info","msg":"finished streaming call with code OK","peer.address":"@","span.kind":"server","system":"grpc","time":"2019-09-17T22:17:19Z"}
/var/log/gitlab/gitlab-rails/production_json.log:{"method":"GET","path":"/root/linux/blob/master/README","format":"json","controller":"Projects::BlobController","action":"show","status":200,"duration":2448.77,"view":0.49,"db":21.63,"time":"2019-09-17T22:17:19.800Z","params":[{"key":"viewer","value":"rich"},{"key":"namespace_id","value":"root"},{"key":"project_id","value":"linux"},{"key":"id","value":"master/README"}],"remote_ip":"[filtered]","user_id":2,"username":"bob","ua":"Mozilla/5.0 (Mac) Gecko Firefox/69.0","queue_duration":3.38,"gitaly_calls":1,"gitaly_duration":0.77,"rugged_calls":4,"rugged_duration_ms":28.74,"correlation_id":"LOt9hgi1TV4"}
```

### Searching in distributed architectures

If you have done some horizontal scaling in your GitLab infrastructure, then
you will need to search across _all_ of your GitLab nodes. You can do this with
some sort of log aggregation software like Loki, ELK, Splunk, or others.

You can use a tool like Ansible or PSSH (parallel SSH) that can execute identical commands across your servers in
parallel, or craft your own solution.
