nginx-service-generator

A simple upstream service generator from zookeeper configuration metadata

Purpose

To dynamically generate nginx upstream proxy configuration based on your zookeeper service discovery meta-data

Features

• Checks in with Zookeeper every 10 seconds
• Hashes the configuration so as not to rewrite unless needed
• Can use a configuration file, as well as optionally overriding parameters via the command line
• Hot configuration file reloading via kill -s SIGHUP <PID> or supplying the -configUpdateInterval flag with a duration, ie. -configUpdateInterval=30s
• Removes services that have no end-points configured

Releases

• Version 0.3.1
• Version 0.3.0
• Version 0.2.0
• Version 0.1.0

Example

Given a zookeeper node information layout as

/services/<my-service-name>/instances
[my-services-server_port]

and a template file like the default

upstream {{.Service}} {
    {{range .UpstreamEndpoints}}server {{.}};{{end}}
}

server {
    listen {{.ListenPort}};
    server_name {{.HostFQDN}};

    location / {
        proxy_set_header HOST               $host;
        proxy_set_header X-Forwarded-Proto  $scheme;
        proxy_set_header X-Real-IP          $remote_addr;
        proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;

        proxy_pass http://{{.Service}};
    }
}

a config file that looks like

[default]
nginx-root = /etc/nginx
zookeeper-nodes = 127.0.0.1:2181
service-root = /services
service-check-interval = 10
nginx-reload-command = sv reload nginx
fqdn-subdomain = api
fqdn-postfix = example.com
listen-port = 80

running the following command

./service-generator -config example.config

will yield a service like

upstream my-service-name {
    server my-services-server:port;
}

server {
    listen 80;
    server_name my-service-name.api.example.com;

    location / {
        proxy_set_header HOST               $host;
        proxy_set_header X-Forwarded-Proto  $scheme;
        proxy_set_header X-Real-IP          $remote_addr;
        proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;

        proxy_pass http://my-service-name;
    }
}

If you wanted to override one or more of your configuration file flags, you can optionally specify a command line parameter, such as

./service-generator -config example.config -fqdn-postfix example2.com

# Will yield a service file looking like

upstream my-service-name {
    server my-services-server:port;
}

server {
    listen 80;
    server_name my-service-name.api.example2.com;

    location / {
        proxy_set_header HOST               $host;
        proxy_set_header X-Forwarded-Proto  $scheme;
        proxy_set_header X-Real-IP          $remote_addr;
        proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;

        proxy_pass http://my-service-name;
    }
}

The resultant configuration file will be soft-linked from sites-available to sites-enabled, and nginx will get reloaded so that the configuration is up to date.

This will continue running in the background, at the interval specified by service-check-interval in the configuration file, or as a command line parameter.

You can create your configuration file using the -dumpflags command line parameter.

./service-generator -dumpflags > default.config

License

2-clause BSD