Name

ngx_lua_upstream - Nginx C module to expose Lua API to ngx_lua for Nginx upstreams

Table of Contents

• Name
• Status
• Synopsis
• Functions
  • get_upstreams
  • get_servers
  • get_primary_peers
  • get_backup_peers
  • set_peer_down
  • add_server
  • add_peer
  • remove_server
  • remove_peer
• TODO
• Compatibility
• Installation
• Author
• Copyright and License
• See Also

Status

This module is still under active development and is considered production ready.

Synopsis

http {
    upstream foo.com {
        server 127.0.0.1 fail_timeout=53 weight=4 max_fails=100;
        server agentzh.org:81;
    }

    upstream bar {
        server 127.0.0.2;
    }

    server {
        listen 8080;

        # sample output for the following /upstream interface:
        # upstream foo.com:
        #     addr = 127.0.0.1:80, weight = 4, fail_timeout = 53, max_fails = 100
        #     addr = 106.187.41.147:81, weight = 1, fail_timeout = 10, max_fails = 1
        # upstream bar:
        #     addr = 127.0.0.2:80, weight = 1, fail_timeout = 10, max_fails = 1

        location = /upstreams {
            default_type text/plain;
            content_by_lua '
                local concat = table.concat
                local upstream = require "ngx.upstream"
                local get_servers = upstream.get_servers
                local get_upstreams = upstream.get_upstreams

                local us = get_upstreams()
                for _, u in ipairs(us) do
                    ngx.say("upstream ", u, ":")
                    local srvs, err = get_servers(u)
                    if not srvs then
                        ngx.say("failed to get servers in upstream ", u)
                    else
                        for _, srv in ipairs(srvs) do
                            local first = true
                            for k, v in pairs(srv) do
                                if first then
                                    first = false
                                    ngx.print("    ")
                                else
                                    ngx.print(", ")
                                end
                                if type(v) == "table" then
                                    ngx.print(k, " = {", concat(v, ", "), "}")
                                else
                                    ngx.print(k, " = ", v)
                                end
                            end
                            ngx.print("\\n")
                        end
                    end
                end
            ';
        }
    }
}

Functions

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get_upstreams

syntax: names = upstream.get_upstreams()

Get a list of the names for all the named upstream groups (i.e., explicit upstream {} blocks).

Note that implicit upstream groups created by proxy_pass and etc are excluded.

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get_servers

syntax: servers = upstream.get_servers(upstream_name)

Get configurations for all the servers in the specified upstream group. Please one server may take multiple addresses when its server name can be resolved to multiple addresses.

The return value is an array-like Lua table. Each table entry is a hash-like Lua table that takes the following keys:

• addr

  socket address(es). can be either a Lua string or an array-like Lua table of Lua strings.

• backup

• fail_timeout

• max_fails

• weight

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get_primary_peers

syntax: peers = upstream.get_primary_peers(upstream_name)

Get configurations for all the primary (non-backup) peers in the specified upstream group.

The return value is an array-like Lua table for all the primary peers. Each table entry is a (nested) hash-like Lua table that takes the following keys:

• current_weight

• effective_weight

• fail_timeout

• fails

• id

  Identifier (ID) for the peer. This ID can be used to reference a peer in a group in the peer modifying API.

• max_fails

• name

  Socket address for the current peer

• weight

• accessed

  Timestamp for the last access (in seconds since the Epoch)

• checked

  Timestamp for the last check (in seconds since the Epoch)

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get_backup_peers

syntax: peers = upstream.get_backup_peers(upstream_name)

Get configurations for all the backup peers in the specified upstream group.

The return value has the same structure as get_primary_peers function.

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set_peer_down

syntax: ok, err = upstream.set_peer_down(upstream_name, is_backup, peer_id, down_value)

Set the "down" (boolean) attribute of the specified peer.

To uniquely specify a peer, you need to specify the upstream name, whether or not it is a backup peer, and the peer id (starting from 0).

Note that this method only changes the peer settings in the current Nginx worker process. You need to synchronize the changes across all the Nginx workers yourself if you want a server-wide change (for example, by means of ngx_lua's ngx.shared.DICT).

Below is an example. Consider we have a "bar" upstream block in nginx.conf:

upstream bar {
    server 127.0.0.2;
    server 127.0.0.3 backup;
    server 127.0.0.4 fail_timeout=23 weight=7 max_fails=200 backup;
}

then

upstream.set_peer_down("bar", false, 0, true)

will turn down the primary peer corresponding to server 127.0.0.2.

Similarly,

upstream.set_peer_down("bar", true, 1, true)

will turn down the backup peer corresponding to server 127.0.0.4 ....

You can turn on a peer again by providing a false value as the 4th argument.

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add_server

syntax: ok,err = upstream.add_server(upstream_name,ip:port,weight,max_fails,fail_timeout,is_backup)

Add a server to upstream. if the server is exist will return err and notes the server is exist.
Note that this method only add a server in the current Nginx worker process. You need to synchronize the changes across all the Nginx workers if you want a server-wide change. Please useing ngx_lua_upstream_dyusc

Warning:
`it also to add server to ngx_http_upstream_server_t structure ,so you should call add_peer.
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add_peer

syntax: ok,err = upstream.add_peer(upstream,ip:port)

Add a server to back-end peers. if back-end peers is exist will return err and notes the peer is exist. it's suitable for ip_hash or round_robin hash and least_conn. Note that this method only add a peer in the current Nginx worker process. You need to synchronize the changes across all the Nginx workers if you want a server-wide change. Please useing ngx_lua_upstream_dyusc
Warning:
if you are using a least_conn and you should update something to below

Modified macro variable 'NGX_HTTP_UPSTREAM_LEAST_CONN' 1 ,it's default 0 at 'lua-upstream-nginx-module/src/ngx_http_lua_upstream_module.h' file.

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remove_server

syntax: ok,err = upstream.remove_server(upstream,ip:port)

Remove a server from upstream. if the server is not exist will return err and notes the server is not found.
Note that this method only remove a server in the current Nginx worker process. You need to synchronize the changes across all the Nginx workers if you want a server-wide change. Please useing ngx_lua_upstream_dyusc Warning:
`it also to add server to ngx_http_upstream_server_t structure ,so you should call add_peer.

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remove_peer

syntax: ok,err = upstream.remove_peer(upstream,ip:port)

Remove a server to back-end peers. if back-end peers not exist will return err and notes the peer is not found. it's suitable for ip_hash or round_robin hash and least_conn.
Note that this method only remove a peer in the current Nginx worker process. You need to synchronize the changes across all the Nginx workers if you want a server-wide change. Please useing ngx_lua_upstream_dyusc Warning:
if you are using a least_conn and you should update something to below

Modified macro variable 'NGX_HTTP_UPSTREAM_LEAST_CONN' 1 ,it's default 0 at 'lua-upstream-nginx-module/src/ngx_http_lua_upstream_module.h' file.

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TODO

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Compatibility

The following versions of OpenResty should work with this module:

• 1.7.10.x (last tested: 1.7.10.2)
• 1.7.7.x (last tested: 1.7.7.2)
• 1.7.4.1
• 1.7.2.1

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Installation

This module is bundled and enabled by default in the OpenResty bundle. And you are recommended to use OpenResty.

1. Grab the nginx source code from nginx.org, for example, the version 1.5.12 (see nginx compatibility),
2. then grab the source code of the ngx_lua as well as its dependencies like LuaJIT.
3. and finally build the source with this module:

wget 'http://nginx.org/download/nginx-1.5.12.tar.gz'
tar -xzvf nginx-1.5.12.tar.gz
cd nginx-1.5.12/

# assuming your luajit is installed to /opt/luajit:
export LUAJIT_LIB=/opt/luajit/lib

# assuming you are using LuaJIT v2.1:
export LUAJIT_INC=/opt/luajit/include/luajit-2.1

# Here we assume you would install you nginx under /opt/nginx/.
./configure --prefix=/opt/nginx \
    --with-ld-opt="-Wl,-rpath,$LUAJIT_LIB" \
    --add-module=/path/to/lua-nginx-module \
    --add-module=/path/to/lua-upstream-nginx-module

make -j2
make install

If you are using ngx_openresty, then you can just add this module to OpenResty like this:

./configure --add-module=/path/to/lua-upstream-nginx-module
make -j2
make install

And you are all set. This module will get bundled into OpenResty in the near future.

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Author

Yichun "agentzh" Zhang (章亦春) [email protected], CloudFlare Inc.

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Copyright and License

This module is licensed under the BSD license.

Copyright (C) 2014-2015, by Yichun "agentzh" Zhang, CloudFlare Inc.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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See Also

• the ngx_lua module: http://github.com/openresty/lua-nginx-module#readme
• the lua-resty-upstream-healthcheck library which makes use of the Lua API provided by this module.

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