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Module ngx-dynamic-resolver-module

Instructions

System will resolver domain in dynamic resolver every few seconds configured.

The module will return addr whose domain is resolved in dynamic resolver, otherwise, the module will add domain into dynamic resolver, resolv domain by event resolver, and call callback when resolved.

Directives

Syntax  : dynamic_refresh_interval time;
Default : dynamic_refresh_interval 5m;
Context : events

Set time interval for DNS query frequency, 0 for shutdown this function.

Syntax  : dynamic_domain_buckets number;
Default : dynamic_domain_buckets 101;
Context : events

Bucket for dynamic resolver domain hash table. Use prime key is Recommended.

Example:

events {
	resolver                  192.168.84.254 valid=1m;
	dynamic_refresh_interval  5m;
	dynamic_domain_buckets    1001;
}

API

header file

For using this API, You should include the header file as below:

#include "ngx_dynamic_resolver.h"

start resolver

void ngx_dynamic_resolver_start_resolver(ngx_str_t *domain,
    ngx_dynamic_resolver_handler_pt h, void *data);

return value:
- None
paras:
- domain: domain for DNS query
- h : callback handler
- data : data for callback

h's protype is:

typedef void (* ngx_dynamic_resolver_handler_pt)(void *data,
    struct sockaddr *sa, socklen_t socklen);

return value:
- None
paras:
- data : user private data set in ngx_dynamic_resolver_start_resolver
- sa : sock address get
- socklen: sock address len, 0 for get none address

gethostbyname

socklen_t ngx_dynamic_resolver_gethostbyname(ngx_str_t *domain, struct sockaddr *sa);

return value:
- socklen for successd
- 0 for failed
paras:
- domain: domain for query
- sa : sock address get

add domain

void ngx_dynamic_resolver_add_domain(ngx_str_t *domain);

return value:
- None
paras:
- domain: domain for query

del domain

void ngx_dynamic_resolver_del_domain(ngx_str_t *domain);

return value:
- None
paras:
- domain: domain for DNS query

Build

cd to NGINX source directory & run this:

./configure --add-module=/path/to/nginx-toolkit-module/
make && make install

Example

See t/ngx_dynamic_resolver_test_module.c as reference

Build:

./configure --with-debug --add-module=/path/to/nginx-toolkit-module/ --add-module=/path/to/nginx-toolkit-module/t
make && make install

Configure:

events {
	resolver                  192.168.84.254 valid=1m;
	dynamic_refresh_interval  5m;
}

http {

	...

	server {

		...

		location /dynamic_resolver_test/ {
			dynamic_resolver_test  192.168.84.4  www.test1.com;
		}
	}
}

Test:

sync resolver

  curl -v 'http://127.0.0.1/dynamic_resolver_test/resolver?domain=www.test1.com&sync=1'

start resolver

  curl -v 'http://127.0.0.1/dynamic_resolver_test/resolver?domain=www.test.com'

del domain

  curl -XDELETE -v 'http://127.0.0.1/dynamic_resolver_test/resolver?domain=www.test.com'

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