Name

ngx_http_expr_module - lazy computed complex variables.

Table of Contents

• Name
• Status
• Synopsis
• Description
• Configuration directives

Status

This library is production ready.

Description

Module makes possible declare complex variables with lazy computation. This is may be used to choose access_log format dynamically.

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Synopsis

http {
    log_format  main  $format;

    access_log  logs/access.log  main;

    expr_max_hash_size 10240;

    server {
        listen 4444;

        location /test1 {
            expr $format '1111 $remote_addr - $remote_user [$time_local] "$request" $status $request_time $upstream_addr';
            return 200 test1;
        }

        location /test2 {
            expr $format '2222 $remote_addr - $remote_user [$time_local] "$request" $status $request_time $upstream_addr';
            return 200 test2;
        }

        location /test3 {
            expr $format '3333 $remote_addr - $remote_user [$time_local] "$request" $status $request_time $upstream_addr';
            echo_exec @inner1;
        }

        location @inner1 {
            echo_exec @inner2;
        }

        location @inner2 {
            return 200 $uri;
        }
    }
}

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Configuration directives

expr_if_empty

• syntax: expr_if_empty $var <complex value>
• context: location

Declare complex variable with lazy computation.

In runtime set value if variable is empty.

Directive is not support inheritance.

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expr

• syntax: expr $var <complex value>
• context: location

Declare complex variable with lazy computation.

Directive is not support inheritance.

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expr_max_hash_size

• syntax: expr $var <complex value>
• default: 1024
• minimum: 256
• context: http,server,location

Maximum number of locations per variable.

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