Who Calls Whom?
By default, logs are written to stdout, in text format.
To enable the access logs:
By default access logs are written to the standard output.
To write the logs into a log file, use the
By default, logs are written using the Common Log Format (CLF).
To write logs in JSON, use
json in the
If the given format is unsupported, the default (CLF) is used instead.
Common 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_router_name>" "<Traefik_server_URL>" <request_duration_in_ms>ms
To write the logs in an asynchronous fashion, specify a
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.
# Configuring a buffer of 100 lines [accessLog] filePath = "/path/to/access.log" bufferingSize = 100
# Configuring a buffer of 100 lines accessLog: filePath: "/path/to/access.log" bufferingSize: 100
# Configuring a buffer of 100 lines --accesslog=true --accesslog.filepath=/path/to/access.log --accesslog.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.
The available filters are:
statusCodes, to limit the access logs to requests with a status codes in the specified range
retryAttempts, to keep the access logs when at least one retry has happened
minDuration, to keep access logs when requests take longer than the specified duration (provided in seconds or as a valid duration format, see time.ParseDuration)
# Configuring Multiple Filters [accessLog] filePath = "/path/to/access.log" format = "json" [accessLog.filters] statusCodes = ["200", "300-302"] retryAttempts = true minDuration = "10ms"
# Configuring Multiple Filters accessLog: filePath: "/path/to/access.log" format: json filters: statusCodes: - "200" - "300-302" retryAttempts: true minDuration: "10ms"
# Configuring Multiple Filters --accesslog=true --accesslog.filepath=/path/to/access.log --accesslog.format=json --accesslog.filters.statuscodes=200,300-302 --accesslog.filters.retryattempts --accesslog.filters.minduration=10ms
Limiting the Fields/Including Headers¶
You can decide to limit the logged fields/headers to a given list with the
Each field can be set to:
keepto keep the value
dropto drop the value
redactto replace the value with "redacted"
# Limiting the Logs to Specific Fields [accessLog] filePath = "/path/to/access.log" format = "json" [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"
# Limiting the Logs to Specific Fields accessLog: filePath: "/path/to/access.log" format: json fields: defaultMode: keep names: ClientUsername: drop headers: defaultMode: keep names: User-Agent: redact Authorization: drop Content-Type: keep
# Limiting the Logs to Specific Fields --accesslog=true --accesslog.filepath=/path/to/access.log --accesslog.format=json --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 --accesslog.fields.headers.names.Content-Type=keep
||The time at which request processing started.|
||The local time at which request processing started.|
||The total time taken (in nanoseconds) by processing the response, including the origin server's time but not the log writing time.|
||The name of the Traefik router.|
||The name of the Traefik backend.|
||The URL of the Traefik backend.|
||The IP:port of the Traefik backend (extracted from
||The remote address in its original form (usually IP:port).|
||The remote IP address from which the client request was received.|
||The remote TCP port from which the client request was received.|
||The username provided in the URL, if present.|
||The HTTP Host header (usually IP:port). This is treated as not a header by the Go API.|
||The HTTP Host server name (not including port).|
||The TCP port from the HTTP Host.|
||The HTTP method.|
||The HTTP request URI, not including the scheme, host or port.|
||The version of HTTP requested.|
||The HTTP scheme requested
||The number of bytes in the request entity (a.k.a. body) sent by the client.|
||The time taken (in nanoseconds) by the origin server ('upstream') to return its response.|
||The content length specified by the origin server, or 0 if unspecified.|
||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.|
||The HTTP status code returned to the client.|
||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.|
||The number of requests received since the Traefik instance started.|
||The response body compression ratio achieved.|
||The processing time overhead (in nanoseconds) caused by Traefik.|
||The amount of attempts the request was retried.|
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
This does not work on Windows due to the lack of USR signals.
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
/usr/share/zoneinfo(based on your distribution) or set the environment variable TZ to the desired timezone
- Specify the field
StartLocalby dropping the field named
StartUTC(available on the default Common Log Format (CLF) as well as JSON)
Example utilizing Docker Compose:
version: "3.7" services: traefik: image: traefik:v2.2 environment: - TZ=US/Alaska command: - --accesslog - --accesslog.fields.names.StartUTC=drop - --providers.docker ports: - 80:80 volumes: - /var/run/docker.sock:/var/run/docker.sock