pg_querier_manager

README

Database load balancer

General overview

The call of the app is to route requests between nodes that performs requests, processes them and responds with processed data. All these nodes have an API interface for performing DB requests and the main goal of the Database load balancer is determinate which node is the most stress-free and route request to it otherwise the load balancer should send a request to the service which will build a new node's instance up and then the balancer will route the request to the new node. Other words, it's kind of nginx but for database request. Also, the balancer uses the database, it stores there the info about current node's allocations and the list of the available nodes.

Configurations

The database load balancer is a configurable application. Here's the default config file which locates at the app's root directory:

config.json

{
  "database": {
    "vendor" : "postgres",
    "host": "localhost",
    "port": 5432,
    "user": "test",
    "password": "test",
    "db_name": "querier_manager",
    "ssl_mode": "disable"
  },
  "web_server": {
    "port": 8080
  },
  "instances_master": {
    "ip_address": "10.0.0.1",
    "port": 80
  }
}

The config file includes three general sections: database, web_server and instances_master.

The database's section includes the general info about how to connect to the database such as:

• vendor - means the database's vendor
• host - the ip address on which run the database
• port - the database port
• user and password - the database's credentials
• db_name - the name of the database which will be used for storing current node's allocations and the list of available nodes

The web server's section has only one configurable parameter - port, this option is determinate on which port will be spun web server up.

The instances master's section has two parameters: ip_address and port. This section uses for configuring the connection to service which deploys new nodes

Building and spinning the application up

To download the app perform the following command:

go get github.com/Andry75/PG_querier_manager

Then navigate to the app's dir:

cd $GOPATH/src/github.com/Andry75/PG_querier_manager

To build the app perform the following command:

go build main.go

To start the app perform the following command:

./main