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Access Logs¶

Who Calls Whom?

By default, logs are written to stdout, in text format.

Configuration¶

To enable the access logs:

File (TOML)

[accessLog]

File (YAML)

accessLog: {}

CLI

--accesslog=true

`filePath`¶

By default access logs are written to the standard output. To write the logs into a log file, use the filePath option.

in the Common Log Format (CLF), extended with additional fields.

`format`¶

By default, logs are written using the Common Log Format (CLF). To write logs in JSON, use json in the format option.

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_frontend_name>" "<Traefik_backend_URL>" <request_duration_in_ms>ms

`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.

File (TOML)

# Configuring a buffer of 100 lines
[accessLog]
  filePath = "/path/to/access.log"
  bufferingSize = 100

File (YAML)

# Configuring a buffer of 100 lines
accessLog:
  filePath: "/path/to/access.log"
  bufferingSize: 100

CLI

# Configuring a buffer of 100 lines
--accesslog=true
--accesslog.filepath="/path/to/access.log"
--accesslog.bufferingsize=100

Filtering¶

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

File (TOML)

# Configuring Multiple Filters
[accessLog]
  filePath = "/path/to/access.log"
  format = "json"

  [accessLog.filters]    
    statusCodes = ["200", "300-302"]
    retryAttempts = true
    minDuration = "10ms"

File (YAML)

# Configuring Multiple Filters
accessLog:
  filePath: "/path/to/access.log"
  format: json
  filters:    
    statusCodes:
    - "200"
    - "300-302"
    retryAttempts: true
    minDuration: "10ms"

CLI

# 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¶

You can decide to limit the logged fields/headers to a given list with the fields.names and fields.header options

Each field can be set to:

keep to keep the value
drop to drop the value
redact to replace the value with "redacted"

The defaultMode for fields.header is drop.

File (TOML)

# 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"

File (YAML)

# Limiting the Logs to Specific Fields
accessLog:
  filePath: "/path/to/access.log"
  format: json
  fields:
    defaultMode: keep
    fields:
      names:
        ClientUsername: drop
      headers:
        defaultMode: keep
        names:
        - User-Agent: redact
        - Authorization: drop
        - Content-Type: keep

CLI

# 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"

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.

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.

Access Logs¶

Configuration¶

filePath¶

format¶

bufferingSize¶

Filtering¶

Limiting the Fields¶

Log Rotation¶

`filePath`¶

`format`¶

`bufferingSize`¶