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ConsulWatcher/config/index.example.js

121 lines
2.7 KiB
JavaScript

const winston = require('winston');
const setIndent = require('./setindent');
const config = {
/*
Consul agent configuration
Determines the agent or server which will be queried and
monitored for the service catalog.
Recommended to be a local agent connected to the cluster.
Passed to the initialization of the Node Consul client.
For all options, see: https://github.com/silas/node-consul#init
*/
consul: {
host: 'pc-mvrenswoude'
},
/*
Logging
See: https://github.com/winstonjs/winston#transports
*/
logging: {
transports: [
new winston.transports.Console({
level: 'debug',
timestamp: true,
format: winston.format.combine(
winston.format.colorize(),
winston.format.simple()
)
})
]
},
onUpdate: [],
afterUpdate: null
};
/*
onUpdate handlers
When a change occurs in the Consul catalog, each handler is called in order.
Callbacks may return a Promise. Note that when using multiple handlers,
they are not awaited immediately but at the end using Promise.all(), which
means the handlers effectively run in parallel.
The catalog parameter has a services property to enumerate the registered
services. See the Readme for the documentation of the ConsulCatalog class.
For more information about a service, including it's address and health,
an additional call to Consul is required. Calling these methods will result
in the service being watched for changes as well.
The second parameter is a reference to the Winston logger instance.
*/
const fs = require('fs').promises;
config.onUpdate.push(async (catalog, logger) =>
{
// Use catalog parameter to generate output
let output = '';
for (const service of catalog.services)
{
let instances = '';
for (const instance of await service.getInstances())
{
instances += setIndent(2, `
Address: ${instance.address}
Port: ${instance.port}
`);
}
output += setIndent(`
Service: ${service.name}
Tags: ${JSON.stringify(service.tags)}
`);
output += instances + '\n';
};
await fs.writeFile('example-output.txt', output);
});
// Example on how to split the update handlers into a separate file
config.onUpdate.push(require('./included.example'));
/*
afterUpdate handler
This is a single handler which is called after all the onUpdate handlers
have finished, including any Promises returned.
It can be used for example to reload a proxy server after the configuration
changes have been written in onUpdate.
*/
config.afterUpdate = (catalog, logger) =>
{
// Call a reload script
}
module.exports = config;