debian-mirror-gitlab/doc/administration/troubleshooting/log_parsing.md

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Parsing GitLab logs with jq

We recommend using log aggregation and search tools like Kibana and Splunk whenever possible, but if they are not available you can still quickly parse GitLab logs in JSON format (the default in GitLab 12.0 and later) using jq.

What is JQ?

As noted in its manual, jq is a command-line JSON processor. The following examples include use cases targeted for parsing GitLab log files.

Parsing Logs

General Commands

Pipe colorized jq output into less

jq . <FILE> -C | less -R

Search for a term and pretty-print all matching lines

grep <TERM> <FILE> | jq .

Skip invalid lines of JSON

jq -cR 'fromjson?' file.json | jq <COMMAND>

By default jq will error out when it encounters a line that is not valid JSON. This skips over all invalid lines and parses the rest.

Parsing production_json.log and api_json.log

Find all requests with a 5XX status code

jq 'select(status >= 500)' <FILE>

Top 10 slowest requests

jq -s 'sort_by(-.duration) | limit(10; .[])' <FILE>

Find and pretty print all requests related to a project

grep <PROJECT_NAME> <FILE> | jq .

Find all requests with a total duration > 5 seconds

jq 'select(.duration > 5000)' <FILE>

Find all project requests with more than 5 rugged calls

grep <PROJECT_NAME> <FILE> | jq 'select(.rugged_calls > 5)'

Find all requests with a Gitaly duration > 10 seconds

jq 'select(.gitaly_duration > 10000)' <FILE>

Find all requests with a queue duration > 10 seconds

jq 'select(.queue_duration > 10000)' <FILE>

Top 10 requests by # of Gitaly calls

jq -s 'map(select(.gitaly_calls != null)) | sort_by(-.gitaly_calls) | limit(10; .[])' <FILE>

Parsing production_json.log

Print the top three controller methods by request volume and their three longest durations

jq -s -r 'group_by(.controller+.action) | sort_by(-length) | limit(3; .[]) | sort_by(-.duration) | "CT: \(length)\tMETHOD: \(.[0].controller)#\(.[0].action)\tDURS: \(.[0].duration),  \(.[1].duration),  \(.[2].duration)"' production_json.log

Example output

CT: 2721   METHOD: SessionsController#new  DURS: 844.06,  713.81,  704.66
CT: 2435   METHOD: MetricsController#index DURS: 299.29,  284.01,  158.57
CT: 1328   METHOD: Projects::NotesController#index DURS: 403.99,  386.29,  384.39

Parsing api_json.log

Print top three routes with request count and their three longest durations

jq -s -r 'group_by(.route) | sort_by(-length) | limit(3; .[]) | sort_by(-.duration) | "CT: \(length)\tROUTE: \(.[0].route)\tDURS: \(.[0].duration),  \(.[1].duration),  \(.[2].duration)"' api_json.log

Example output

CT: 2472 ROUTE: /api/:version/internal/allowed   DURS: 56402.65,  38411.43,  19500.41
CT: 297  ROUTE: /api/:version/projects/:id/repository/tags       DURS: 731.39,  685.57,  480.86
CT: 190  ROUTE: /api/:version/projects/:id/repository/commits    DURS: 1079.02,  979.68,  958.21

Parsing gitaly/current

Find all Gitaly requests sent from web UI

jq 'select(."grpc.meta.client_name" == "gitlab-web")' current

Find all failed Gitaly requests

jq 'select(."grpc.code" != null and ."grpc.code" != "OK")' current

Find all requests that took longer than 30 seconds

jq 'select(."grpc.time_ms" > 30000)' current

Print top ten projects by request volume and their three longest durations

jq --raw-output --slurp '
  map(
    select(
      ."grpc.request.glProjectPath" != null
      and ."grpc.request.glProjectPath" != ""
      and ."grpc.time_ms" != null
    )
  )
  | group_by(."grpc.request.glProjectPath")
  | sort_by(-length)
  | limit(10; .[])
  | sort_by(-."grpc.time_ms")
  | [
      length,
      .[0]."grpc.time_ms",
      .[1]."grpc.time_ms",
      .[2]."grpc.time_ms",
      .[0]."grpc.request.glProjectPath"
    ]
  | @sh' /var/log/gitlab/gitaly/current \
| awk 'BEGIN { printf "%7s %10s %10s %10s\t%s\n", "CT", "MAX DURS", "", "", "PROJECT" }
  { printf "%7u %7u ms, %7u ms, %7u ms\t%s\n", $1, $2, $3, $4, $5 }'

Example output

   CT    MAX DURS                              PROJECT
  206    4898 ms,    1101 ms,    1032 ms      'groupD/project4'
  109    1420 ms,     962 ms,     875 ms      'groupEF/project56'
  663     106 ms,      96 ms,      94 ms      'groupABC/project123'
  ...