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Document updated on Oct 24, 2024

HTTP Server Settings

KrakenD starts an HTTP server to offer the API Gateway server. You can personalize some of the settings used to start the service and also override the default settings of the underlying Go standard library.

If you want to customize any of the settings below, they must be written at the top level of the configuration.

Fields of "_root"
* 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"
disable_rest boolean
Endpoints require in its endpoint definition the usage of a RESTful pattern. If you require unrestful patterns, like /file.{ext} (instead of its RESTful counterpart /file/{ext}), then you must set this parameter to true.

You can use multiple variables if needed, but only one can be in an unrestful position, and when you do, it must be in the last position of the definition. E.g.: you can declare an endpoint /file/{name}/base.{ext} but you cannot do /file.{ext}.json because the variable {ext} is not in the last position of the definitino, and therefore the remaining path after {ext} is ignored by the router.
Defaults to false
idle_timeout string
The maximum amount of time to wait for the next request when keep-alives are enabled. If idle_timeout is zero, the value of read_timeout is used. If both are zero, there is no timeout.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "0s"
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"
max_header_bytes integer
Allows overriding the maximum size of headers sent in bytes. It does not limit the request body. When the value is zero, the default is used instead (1MB)
Defaults to 1000000
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
read_header_timeout string
The amount of time allowed to read request headers. The connection’s read deadline is reset after reading the headers and the Handler can decide what is considered too slow for the body.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "0s"
read_timeout string
Is the maximum duration for reading the entire request, including the body. Because read_timeout does not let Handlers make per-request decisions on each request body’s acceptable deadline or upload rate, most users will prefer to use read_header_timeout. It is valid to use them both.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "0s"
sequential_start boolean
A sequential start registers all async agents in order, allowing you to have the starting logs in sequential order. A non-sequential start is much faster, but logs are harder to follow.
Defaults to false
use_h2c boolean
Enable the support for HTTP/2 with no TLS (clear text). This option is less secure and less performant, use with caution.
Defaults to false
write_timeout string
Maximum duration before timing out writes of the response.
Specify units using ns (nanoseconds), us or µs (microseconds), ms (milliseconds), s (seconds), m (minutes), or h (hours).
Defaults to "0s"

Override settings using environment vars

When you declare in the configuration file any of the HTTP server settings declared above, you can override its value through environment variables when starting the server.

All the environment variables have the same name are the same settings above in uppercase and with the KRAKEND_ preffix. For instance, looking at the list of settings above, you could override:

  • KRAKEND_PORT
  • KRAKEND_READ_TIMEOUT
  • KRAKEND_READ_HEADER_TIMEOUT
  • KRAKEND_WRITE_TIMEOUT
  • KRAKEND_IDLE_TIMEOUT
  • KRAKEND_USE_H2C
  • etc…

You can start KrakenD with the desired variables to override what you have in the configuration:

Term 

$KRAKEND_PORT=8000 KRAKEND_READ_TIMEOUT="1s" krakend run -c krakend.json

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