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Service Settings Configuration

Document updated on Oct 24, 2023

We call service settings (or the service layer) those parameters that allow you to change how KrakenD behaves globally (and not to a specific call). They determine how you start the HTTP server, enforce security parameters, or define behavioral options like which reporting activities occur, to name a few examples.

Examples of service settings are, the listening port, disabling keep alives, enabling metrics and traces, listening https, or enabling CORS to name a few.

If you haven’t done it yet, read Understanding the configuration file.

All service settings are written directly in the root of the configuration file or its corresponding extra_config. So, for instance, here there is a configuration file describing a service listening on port 8080 with extended logging enabled:

{
    "version": 3,
    "port": 8080,
    "output_encoding": "json",
    "host": ["http://myapi"],
    "timeout": "3s",
    "cache_ttl": "60s",
    "listen_ip": "192.168.1.3",
    "endpoints": [],
    "extra_config": {
      "telemetry/logging": {
        "level": "WARNING",
        "syslog": true,
        "stdout": true
      }
    }
}

The service accepts numerous configuration options that you’ll find explained through the rest of the documentation, but here is a preview of the most important ones:

Fields of "false"
* required fields
cache_ttl

string
Sets a default Cache-Control: public, max-age=%d header to all endpoints where %d is the conversion to seconds of any duration you write, indicating for how long the client (or CDN) can cache the content of the request. You can override this value per endpoint, but setting an endpoint to 0 will use the default value instead. Notice that KrakenD does not cache the content with this parameter, but tells the client how to do it. Defaults to 0s (no cache). For KrakenD cache, see backend caching.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "0s"
endpoints

array
Your API contract, or the list of all paths recognized by this gateway. The paths /__health/, /__debug/, /__echo/, /__catchall, and /__stats/ are reserved by the system and you cannot declare them. Their existence depends on their respective settings.
extra_config

object
The optional configuration that extends the core functionality of the gateway is specified here. The extra_config at this level enables service components, meaning that they apply globally to all endpoints or activity.
host

array
The default host list for all backends if they specify none.
listen_ip

string
The IP address that KrakenD listens to in IPv4 or IPv6. An empty string, or no declaration at all means listening on all interfaces. The inclusion of :: is meant for IPv6 format only (this is not the port). Examples of valid addresses are 192.0.2.1 (IPv4), 2001:db8::68 (IPv6). The values :: and 0.0.0.0 listen to all addresses and both are valid for IPv4 and IPv6 simultaneously.
Examples: "172.12.1.1" , "::1"
Defaults to "0.0.0.0"
output_encoding

string
The encoding used to display the content to the end-user. This setting is the default for all endpoints, unless they have another output_encoding overrinding this value.
Possible values are: "json" , "fast-json" , "json-collection" , "xml" , "negotiate" , "string" , "no-op"
Defaults to "json"
port

integer
The TCP port where KrakenD is listening to. Recommended value is in the range 1024-65535 to run as an unpriviliged user
Defaults to 8080
timeout

string
Defines a default timeout for all endpoints. Can be overriden per endpoint.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "2s"
version  *

integer
The syntax version tells KrakenD how to read this configuration. This is not the KrakenD version. Each KrakenD version is linked to a syntax version, and since KrakenD v2.0 the version must be 3
Possible values are: 3

Other service-level settings you can add:

Scarf

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