traefik/docs/configuration/logs.md

Logs Definition

Reference

TOML

logLevel = "INFO"

[traefikLog]
  filePath = "/path/to/traefik.log"
  format   = "json"

[accessLog]
  filePath = "/path/to/access.log"
  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"
        "Content-Type" = "keep"
        # ...

CLI

For more information about the CLI, see the documentation about Traefik command.

--logLevel="DEBUG"
--traefikLog.filePath="/path/to/traefik.log"
--traefikLog.format="json"
--accessLog.filePath="/path/to/access.log"
--accessLog.format="json"
--accessLog.filters.statusCodes="200,300-302"
--accessLog.filters.retryAttempts="true"
--accessLog.filters.minDuration="10ms"
--accessLog.fields.defaultMode="keep"
--accessLog.fields.names="Username=drop Hostname=drop"
--accessLog.fields.headers.defaultMode="keep"
--accessLog.fields.headers.names="User-Agent=redact Authorization=drop Content-Type=keep"

Traefik Logs

By default the Traefik log is written to stdout in text format.

To write the logs into a log file specify the filePath:

[traefikLog]
  filePath = "/path/to/traefik.log"

To write JSON format logs, specify json as the format:

[traefikLog]
  filePath = "/path/to/traefik.log"
  format   = "json"

Deprecated way (before 1.4):

!!! danger "DEPRECATED" traefikLogsFile is deprecated, use traefikLog instead.

# Traefik logs file
# If not defined, logs to stdout
#
# DEPRECATED - see [traefikLog] lower down
# In case both traefikLogsFile and traefikLog.filePath are specified, the latter will take precedence.
# Optional
#
traefikLogsFile = "log/traefik.log"

To customize the log level:

# Log level
#
# Optional
# Default: "ERROR"
#
# Accepted values, in order of severity: "DEBUG", "INFO", "WARN", "ERROR", "FATAL", "PANIC"
# Messages at and above the selected level will be logged.
#
logLevel = "ERROR"

Access Logs

Access logs are written when [accessLog] is defined. By default it will write to stdout and produce logs in the textual Common Log Format (CLF), extended with additional fields.

To enable access logs using the default settings just add the [accessLog] entry:

[accessLog]

To write the logs into a log file specify the filePath:

[accessLog]
filePath = "/path/to/access.log"

To write JSON format logs, specify json as the format:

[accessLog]
filePath = "/path/to/access.log"
format = "json"

To write the logs in async, specify bufferingSize as the format (must be >0):

[accessLog]
filePath = "/path/to/access.log"
# Buffering Size
#
# Optional
# Default: 0
#
# Number of access log lines to process in a buffered way.
#
bufferingSize = 100

To filter logs you can specify a set of filters which are logically "OR-connected". Thus, specifying multiple filters will keep more access logs than specifying only one:

[accessLog]
filePath = "/path/to/access.log"
format = "json"

  [accessLog.filters]

  # statusCodes: keep access logs with status codes in the specified range
  #
  # Optional
  # Default: []
  #
  statusCodes = ["200", "300-302"]

  # retryAttempts: keep access logs when at least one retry happened
  #
  # Optional
  # Default: false
  #
  retryAttempts = true

  # minDuration: keep access logs when request took longer than the specified duration
  #
  # Optional
  # Default: 0
  #
  minDuration = "10ms"

To customize logs format:

[accessLog]
filePath = "/path/to/access.log"
format = "json"

  [accessLog.filters]

  # statusCodes keep only access logs with status codes in the specified range
  #
  # Optional
  # Default: []
  #
  statusCodes = ["200", "300-302"]

  [accessLog.fields]

  # defaultMode
  #
  # Optional
  # Default: "keep"
  #
  # Accepted values "keep", "drop"
  #
  defaultMode = "keep"

  # Fields map which is used to override fields defaultMode
  [accessLog.fields.names]
    "ClientUsername" = "drop"
    # ...

  [accessLog.fields.headers]
    # defaultMode
    #
    # Optional
    # Default: "keep"
    #
    # Accepted values "keep", "drop", "redact"
    #
    defaultMode = "keep"
    # Fields map which is used to override headers defaultMode
    [accessLog.fields.headers.names]
      "User-Agent" = "redact"
      "Authorization" = "drop"
      "Content-Type" = "keep"
      # ...

List of all 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 by processing the response, including the origin server's time but not the log writing time.
FrontendName	The name of the Traefik frontend.
BackendName	The name of the Traefik backend.
BackendURL	The URL of the Traefik backend.
BackendAddr	The IP:port of the Traefik backend (extracted from BackendURL)
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.
RequestLine	RequestMethod + RequestPath + RequestProtocol
RequestContentSize	The number of bytes in the request entity (a.k.a. body) sent by the client.
OriginDuration	The time taken 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.
OriginStatusLine	OriginStatus + Status code explanation
DownstreamStatus	The HTTP status code returned to the client.
DownstreamStatusLine	DownstreamStatus + 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 caused by Traefik.
RetryAttempts	The amount of attempts the request was retried.

Deprecated way (before 1.4):

!!! danger "DEPRECATED" accessLogsFile is deprecated, use accessLog instead.

# Access logs file
#
# DEPRECATED - see [accessLog]
#
accessLogsFile = "log/access.log"

CLF - Common Log Format

By default, Traefik use the CLF (common) as access log format.

<remote_IP_address> - <client_user_name_if_available> [<timestamp>] "<request_method> <request_path> <request_protocol>" <origin_server_HTTP_status> <origin_server_content_size> "<request_referrer>" "<request_user_agent>" <number_of_requests_received_since_Traefik_started> "<Traefik_frontend_name>" "<Traefik_backend_URL>" <request_duration_in_ms>ms 

Log Rotation

Traefik will 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.

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

Time Zones

The timestamp of each log line is in UTC time by default.

If you want to use local timezone, you need to ensure the 3 following elements:

1. Provide the timezone data into /usr/share/zoneinfo
2. Set the environement variable TZ to the timezone to be used
3. Specify the field StartLocal instead of StartUTC (works on default Common Log Format (CLF) as well as JSON)

Example using docker-compose:

version: '3'

services:
  traefik:
    image: containous/traefik:[latest stable version]
    ports:
      - "80:80"
    environment:
      - "TZ=US/Alaska"
    command:
      - --docker
      - --accesslog
      - --accesslog.fields.names="StartUTC=drop"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
      - "/usr/share/zoneinfo:/usr/share/zoneinfo:ro"