A simple example to demonstrate use of local variables in Jsonnet.

jsonnet_local_variables_example.jsonnet

local host = '10.0.0.120'; // Standard local variable ends with semicolon(;).
local http_port = 8080;

{
    local db_port = 3128, // A local variable next to JSON fields ends with comma(,).
    app_protocol:: 'http', // A special hidden variable next to fields use (::) instead of (=) or (:).
    environment_config: {
        app: {
            name: 'Sample app',
            url: $.app_protocol + '://' + host + ':' + http_port + 'app/'
        },
        database: {
            name: "mysql database",
            username: "user",
            password: "password",
            host: host,
            port: db_port,
        },
        rest_api: $.app_protocol + '://' + host + ':' + http_port + '/v2/api/'
    }
}