Logs & AccessLogs
- Logs
  - Configuration Example
  - Configuration Options
- AccessLogs
  - Configuration Example
  - Configuration Options

Logs & AccessLogs

Logs

Logs concern everything that happens to Traefik itself (startup, configuration, events, shutdown, and so on).

Configuration Example

File (YAML)

log:
  filePath: "/path/to/log-file.log"
  format: json
  level: INFO

File (TOML)

[log]
  filePath = "/path/to/log-file.log"
  format = "json"
  level = "INFO"

CLI

--log.filePath=/path/to/log-file.log
--log.format=json
--log.level=INFO

Configuration Options

The section below describe how to configure Traefik logs using the static configuration.

Field	Description	Default	Required
`log.filePath`	By default, the logs are written to the standard output. You can configure a file path instead using the `filePath` option.	-	No
`log.format`	Log format (`common`or `json`). The fields displayed with the format `common` cannot be customized.	“common”	No
`log.level`	Log level (`TRACE`, `DEBUG`, `INFO`, `WARN`, `ERROR`, `FATAL`, and `PANIC`)	ERROR	No
`log.noColor`	When using the format `common`, disables the colorized output.	false	No
`log.maxSize`	Maximum size in megabytes of the log file before it gets rotated.	100MB	No
`log.maxAge`	Maximum number of days to retain old log files based on the timestamp encoded in their filename. A day is defined as 24 hours and may not exactly correspond to calendar days due to daylight savings, leap seconds, etc. By default files are not removed based on their age.	0	No
`log.maxBackups`	Maximum number of old log files to retain. The default is to retain all old log files.	0	No
`log.compress`	Compress log files in gzip after rotation.	false	No

AccessLogs

Configuration Example

File (YAML)

accessLog:
  # JSON format
  format: json
  # Filter on status codes, retry attempts and minimal duration
  filters:
    statusCodes:
      - "200"
      - "300-302"
    retryAttempts: true
    minDuration: "10ms"
  fields:
    # Keep all the fields by default
    defaultMode: keep
    names:
      # Drop the Field ClientUserName
      ClientUsername: drop
    headers:
      # Keep all the headers by default
      defaultMode: keep
      names:
        # Redact the User-Agent header value
        User-Agent: redact
        # Drop the Authorization header value
        Authorization: drop

File (TOML)

[accessLog]
  format = "json"
  [accessLog.filters]
    statusCodes = [ "200", "300-302" ]
    retryAttempts = true
    minDuration = "10ms"
  [accessLog.fields]
    defaultMode = "keep"
    [accessLog.fields.names]
      ClientUsername = "drop"
    [accessLog.fields.headers]
      defaultMode = "keep"
      [accessLog.fields.headers.names]
        User-Agent = "redact"
        Authorization = "drop"

CLI

--accesslog=true
--accesslog.format=json
--accesslog.filters.statuscodes=200,300-302
--accesslog.filters.retryattempts
--accesslog.filters.minduration=10ms
--accesslog.fields.defaultmode=keep
--accesslog.fields.names.ClientUsername=drop
--accesslog.fields.headers.defaultmode=keep
--accesslog.fields.headers.names.User-Agent=redact
--accesslog.fields.headers.names.Authorization=drop

Configuration Options

The section below describes how to configure Traefik access logs using the static configuration.

Field	Description	Default	Required
`accesslog.filePath`	By default, the access logs are written to the standard output. You can configure a file path instead using the `filePath` option.		No
`accesslog.format`	By default, logs are written using the Common Log Format (CLF). To write logs in JSON, use `json` in the `format` option. If the given format is unsupported, the default (CLF) is used instead. More information about CLF fields here.	“common”	No
`accesslog.bufferingSize`	To write the logs in an asynchronous fashion, specify a `bufferingSize` option. This option represents the number of log lines Traefik will keep in memory before writing them to the selected output. In some cases, this option can greatly help performances.	0	No
`accesslog.addInternals`	Enables access logs for internal resources (e.g.: `ping@internal`).	false	No
`accesslog.filters.statusCodes`	Limit the access logs to requests with a status codes in the specified range.	false	No
`accesslog.filters.retryAttempts`	Keep the access logs when at least one retry has happened.	false	No
`accesslog.filters.minDuration`	Keep access logs when requests take longer than the specified duration (provided in seconds or as a valid duration format, see time.ParseDuration).	0	No
`accesslog.fields.defaultMode`	Mode to apply by default to the access logs fields (`keep`, `redact` or `drop`).	keep	No
`accesslog.fields.names`	Set the fields list to display in the access logs (format `name:mode`). Available fields list here.	-	No
`accesslog.headers.defaultMode`	Mode to apply by default to the access logs headers (`keep`, `redact` or `drop`).	drop	No
`accesslog.headers.names`	Set the headers list to display in the access logs (format `name:mode`).	-	No

CLF format fields

Below the fields displayed with the CLF format:

<remote_IP_address> - <client_user_name_if_available> [<timestamp>] 
"<request_method> <request_path> <request_protocol>" <HTTP_status> <content-length> 
"<request_referrer>" "<request_user_agent>" <number_of_requests_received_since_Traefik_started>
"<Traefik_router_name>" "<Traefik_server_URL>" <request_duration_in_ms>ms

Available Fields

Field	Description
`StartUTC`	The time at which request processing started.
`StartLocal`	The local time at which request processing started.
`Duration`	The total time taken (in nanoseconds) by processing the response, including the origin server’s time but not the log writing time.
`RouterName`	The name of the Traefik router.
`ServiceName`	The name of the Traefik backend.
`ServiceURL`	The URL of the Traefik backend.
`ServiceAddr`	The IP:port of the Traefik backend (extracted from `ServiceURL`).
`ClientAddr`	The remote address in its original form (usually IP:port).
`ClientHost`	The remote IP address from which the client request was received.
`ClientPort`	The remote TCP port from which the client request was received.
`ClientUsername`	The username provided in the URL, if present.
`RequestAddr`	The HTTP Host header (usually IP:port). This is treated as not a header by the Go API.
`RequestHost`	The HTTP Host server name (not including port).
`RequestPort`	The TCP port from the HTTP Host.
`RequestMethod`	The HTTP method.
`RequestPath`	The HTTP request URI, not including the scheme, host or port.
`RequestProtocol`	The version of HTTP requested.
`RequestScheme`	The HTTP scheme requested `http` or `https`.
`RequestLine`	The `RequestMethod`, + `RequestPath` and `RequestProtocol`.
`RequestContentSize`	The number of bytes in the request entity (a.k.a. body) sent by the client.
`OriginDuration`	The time taken (in nanoseconds) by the origin server (‘upstream’) to return its response.
`OriginContentSize`	The content length specified by the origin server, or 0 if unspecified.
`OriginStatus`	The HTTP status code returned by the origin server. If the request was handled by this Traefik instance (e.g. with a redirect), then this value will be absent (0).
`OriginStatusLine`	`OriginStatus` + Status code explanation
`DownstreamStatus`	The HTTP status code returned to the client.
`DownstreamStatusLine`	The `DownstreamStatus` and status code explanation.
`DownstreamContentSize`	The number of bytes in the response entity returned to the client. This is in addition to the “Content-Length” header, which may be present in the origin response.
`RequestCount`	The number of requests received since the Traefik instance started.
`GzipRatio`	The response body compression ratio achieved.
`Overhead`	The processing time overhead (in nanoseconds) caused by Traefik.
`RetryAttempts`	The amount of attempts the request was retried.
`TLSVersion`	The TLS version used by the connection (e.g. `1.2`) (if connection is TLS).
`TLSCipher`	The TLS cipher used by the connection (e.g. `TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA`) (if connection is TLS).
`TLSClientSubject`	The string representation of the TLS client certificate’s Subject (e.g. `CN=username,O=organization`).

Log Rotation

Traefik close and reopen its log files, assuming they’re configured, on receipt of a USR1 signal. This allows the logs to be rotated and processed by an external program, such as logrotate.

Warning

This does not work on Windows due to the lack of USR signals.

Time Zones

Traefik will timestamp each log line in UTC time by default.

It is possible to configure the Traefik to timestamp in a specific timezone by ensuring the following configuration has been made in your environment:

Provide time zone data to /etc/localtime or /usr/share/zoneinfo (based on your distribution) or set the environment variable TZ to the desired timezone.
Specify the field StartLocal by dropping the field named StartUTC (available on the default Common Log Format (CLF) as well as JSON): accesslog.fields.names.StartUTC=drop.

Example utilizing Docker Compose:

version: "3.7"
services:
  traefik:
    image: traefik:v3.2
    environment:
      - TZ=US/Alaska
    command:
      - --accesslog.fields.names.StartUTC=drop
      - --providers.docker
    ports:
      - 80:80
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

Using Traefik OSS in Production?

If you are using Traefik at work, consider adding enterprise-grade API gateway capabilities or commercial support for Traefik OSS.

Adding API Gateway capabilities to Traefik OSS is fast and seamless. There’s no rip and replace and all configurations remain intact. See it in action via this short video.