File Log

Append request and response data to a log file on disk.

It is not recommended to use this plugin in production, it would be better to use another logging plugin, for example syslog, in those cases. Due to system limitations this plugin uses blocking file i/o, which will hurt performance, and hence is an anti-pattern for Kong installations.

Terminology

• plugin: a plugin executing actions inside Kong before or after a request has been proxied to the upstream API.
• Service: the Kong entity representing an external upstream API or microservice.
• Route: the Kong entity representing a way to map downstream requests to upstream services.
• Consumer: an entity that makes requests for Kong to proxy; it represents either a user or an external service.
• Credential: a unique string associated with a Consumer, also referred to as an API key.
• Upstream service: this refers to your own API/service sitting behind Kong, to which client requests are forwarded.

Configuration

This plugin is compatible with requests with the following protocols:

• http
• https
• grpc
• grpcs

This plugin is compatible with DB-less mode.

Enabling the plugin on a Service

$ curl -X POST http://kong:8001/services/{service}/plugins \
    --data "name=file-log"  \
    --data "config.path=/tmp/file.log"

plugins:
- name: file-log
  service: {service}
  config: 
    path: /tmp/file.log

{service} is the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

$ curl -X POST http://kong:8001/routes/{route}/plugins \
    --data "name=file-log"  \
    --data "config.path=/tmp/file.log"

plugins:
- name: file-log
  route: {route}
  config: 
    path: /tmp/file.log

{route} is the id or name of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

$ curl -X POST http://kong:8001/consumers/{consumer}/plugins \
    --data "name=file-log"  \
    --data "config.path=/tmp/file.log"

plugins:
- name: file-log
  consumer: {consumer}
  config: 
    path: /tmp/file.log

{consumer} is the id or username of the Consumer that this plugin configuration will target.

You can combine consumer.id and service.id in the same request, to further narrow the scope of the plugin.

Global plugins

A plugin which is not associated to any Service, Route, or Consumer (or API, if you are using an older version of Kong) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

• Using a database, all plugins can be configured using the http://kong:8001/plugins/ endpoint.
• Without a database, all plugins can be configured via the plugins: entry on the declarative configuration file.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Log Format

Every request will be logged separately in a JSON object separated by a new line \n, with the following format:

{
    "request": {
        "method": "GET",
        "uri": "/get",
        "url": "http://httpbin.org:8000/get",
        "size": "75",
        "querystring": {},
        "headers": {
            "accept": "*/*",
            "host": "httpbin.org",
            "user-agent": "curl/7.37.1"
        },
        "tls": {
            "version": "TLSv1.2",
            "cipher": "ECDHE-RSA-AES256-GCM-SHA384",
            "supported_client_ciphers": "ECDHE-RSA-AES256-GCM-SHA384",
            "client_verify": "NONE"
        }
    },
    "upstream_uri": "/",
    "response": {
        "status": 200,
        "size": "434",
        "headers": {
            "Content-Length": "197",
            "via": "kong/0.3.0",
            "Connection": "close",
            "access-control-allow-credentials": "true",
            "Content-Type": "application/json",
            "server": "nginx",
            "access-control-allow-origin": "*"
        }
    },
    "tries": [
        {
            "state": "next",
            "code": 502,
            "ip": "127.0.0.1",
            "port": 8000
        },
        {
            "ip": "127.0.0.1",
            "port": 8000
        }
    ],
    "authenticated_entity": {
        "consumer_id": "80f74eef-31b8-45d5-c525-ae532297ea8e",
        "id": "eaa330c0-4cff-47f5-c79e-b2e4f355207e"
    },
    "route": {
        "created_at": 1521555129,
        "hosts": null,
        "id": "75818c5f-202d-4b82-a553-6a46e7c9a19e",
        "methods": null,
        "paths": [
            "/example-path"
        ],
        "preserve_host": false,
        "protocols": [
            "http",
            "https"
        ],
        "regex_priority": 0,
        "service": {
            "id": "0590139e-7481-466c-bcdf-929adcaaf804"
        },
        "strip_path": true,
        "updated_at": 1521555129
    },
    "service": {
        "connect_timeout": 60000,
        "created_at": 1521554518,
        "host": "example.com",
        "id": "0590139e-7481-466c-bcdf-929adcaaf804",
        "name": "myservice",
        "path": "/",
        "port": 80,
        "protocol": "http",
        "read_timeout": 60000,
        "retries": 5,
        "updated_at": 1521554518,
        "write_timeout": 60000
    },
    "workspaces": [
        {
            "id":"b7cac81a-05dc-41f5-b6dc-b87e29b6c3a3",
            "name": "default"
        }
    ],
    "consumer": {
        "username": "demo",
        "created_at": 1491847011000,
        "id": "35b03bfc-7a5b-4a23-a594-aa350c585fa8"
    },
    "latencies": {
        "proxy": 1430,
        "kong": 9,
        "request": 1921
    },
    "client_ip": "127.0.0.1",
    "started_at": 1433209822425
}

A few considerations on the above JSON object:

• request contains properties about the request sent by the client
• response contains properties about the response sent to the client
• tries contains the list of (re)tries (successes and failures) made by the load balancer for this request
• route contains Kong properties about the specific Route requested
• service contains Kong properties about the Service associated with the requested Route
• authenticated_entity contains Kong properties about the authenticated credential (if an authentication plugin has been enabled)
• workspaces contains Kong properties of the Workspaces associated with the requested Route. Only in Kong Enterprise version >= 0.34.
• consumer contains the authenticated Consumer (if an authentication plugin has been enabled)
• latencies contains some data about the latencies involved:
  • proxy is the time it took for the final service to process the request
  • kong is the internal Kong latency that it took to run all the plugins
  • request is the time elapsed between the first bytes were read from the client and after the last bytes were sent to the client. Useful for detecting slow clients.
• client_ip contains the original client IP address
• started_at contains the UTC timestamp of when the request has started to be processed.

Kong Process Errors

This logging plugin will only log HTTP request and response data. If you are looking for the Kong process error file (which is the nginx error file), then you can find it at the following path: {prefix}/logs/error.log