nginx / current / reference / stream-ngx_stream_keyval_module.html

Module ngx_stream_keyval_module

The ngx_stream_keyval_module module (1.13.7) creates variables with values taken from key-value pairs managed by the API.

This module is available as part of our commercial subscription .

Example Configuration

http {

    server {
        location /api {
            api write=on;

stream {

    keyval_zone zone=one:32k state=/var/lib/nginx/state/one.keyval;
    keyval      $ssl_server_name $name zone=one;

    server {
        listen              12345 ssl;
        proxy_pass          $name;
        ssl_certificate     /usr/local/nginx/conf/cert.pem;
        ssl_certificate_key /usr/local/nginx/conf/cert.key;


Syntax: keyval key $variable zone=name;
Context: stream

Creates a new $variable whose value is looked up by the key in the key-value database. Matching rules are defined by the type parameter of the keyval_zone directive. The database is stored in a shared memory zone specified by the zone parameter.

Syntax: keyval_zone zone=name:size [state=file] [timeout=time] [type=string|ip|prefix] [sync];
Context: stream

Sets the name and size of the shared memory zone that keeps the key-value database. Key-value pairs are managed by the API.

The optional state parameter specifies a file that keeps the current state of the key-value database in the JSON format and makes it persistent across nginx restarts.


keyval_zone zone=one:32k state=/var/lib/nginx/state/one.keyval; # path for Linux
keyval_zone zone=one:32k state=/var/db/nginx/state/one.keyval;  # path for FreeBSD

The optional timeout parameter (1.15.0) sets the time after which key-value pairs are removed from the zone.

The optional type parameter (1.17.1) activates an extra index optimized for matching the key of a certain type and defines matching rules when evaluating a keyval $variable.

The index is stored in the same shared memory zone and thus requires additional storage.

default, no index is enabled; variable lookup is performed using exact match of the record key and a search key
the search key is the textual representation of IPv4 or IPv6 address or CIDR range; to match a record key, the search key must belong to a subnet specified by a record key or exactly match an IP address
variable lookup is performed using prefix match of a record key and a search key (1.17.5); to match a record key, the record key must be a prefix of the search key

The optional sync parameter (1.15.0) enables synchronization of the shared memory zone. The synchronization requires the timeout parameter to be set.

If the synchronization is enabled, removal of key-value pairs (no matter one or all) will be performed only on a target cluster node. The same key-value pairs on other cluster nodes will be removed upon timeout.