113 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			113 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2016 MariaDB Corporation Ab
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|  *
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|  * Use of this software is governed by the Business Source License included
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|  * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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|  *
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|  * Change Date: 2025-01-18
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|  *
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|  * On the date above, in accordance with the Business Source License, use
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|  * of this software will be governed by version 2 or later of the General
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|  * Public License.
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|  */
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| require('./common.js')()
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| 
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| function waitUntilZero(host, target, path, timeout) {
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|     return new Promise((resolve, reject) => {
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|         const interval = 2 // How often we poll the value
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|         var total = 0 // Estimation of how long we've been waiting
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| 
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|         // Using a timer will slow down the initial check but given that the idea is to drain the
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|         // node, it shouldn't be that problematic
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|         var timer = setInterval(() => {
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|             total += interval
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| 
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|             // Read and extract the value
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| 
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|             // Note: It is possible that the interval between requests is less than the configured 2
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|             // seconds since doing the request itself takes some time. This means that it's also
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|             // possible that parallel requests are executed which could cause problems. Upgrading to
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|             // a newer Node.js would allow the use of async/await which should make these sorts of
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|             // things easier to deal with.
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|             doRequest(host, target, (res) => {
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|                 var v = _.get(res, path, -1)
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| 
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|                 if (v <= 0 || total >= timeout) {
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|                     // Value is zero or the timeout was hit
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|                     clearInterval(timer)
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| 
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|                     if (v == -1) {
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|                         // This should never happen as long as correct versions are used
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|                         reject('Invalid path: ' + path)
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|                     } else if (total >= timeout) {
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|                         reject('Drain timeout exceeded')
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|                     } else {
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|                         resolve()
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|                     }
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|                 }
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|             })
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|             .catch((err) => reject(err))
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| 
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|         }, 2000)
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|     })
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| }
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| 
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| exports.command = 'drain <command>'
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| exports.desc = 'Drain objects'
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| exports.handler = function() {}
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| exports.builder = function(yargs) {
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|     yargs
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|         .group(['drain-timeout'], 'Drain options:')
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|         .option('drain-timeout', {
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|             describe: 'Timeout for the drain operation in seconds. If exceeded, the server ' +
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|                 'is added back to all services without putting it into maintenance mode.',
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|             default: 90,
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|             type: 'number'
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|         })
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|         .command('server <server>', 'Drain a server of connections', function(yargs) {
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|             return yargs.epilog('This command drains the server of connections by first removing it ' +
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|                                 'from all services after which it waits until all connections are ' +
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|                                 'closed. When all connections are closed, the server is put into the ' +
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|                                 '`maintenance` state and added back to all the services where it was ' +
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|                                 'removed from. To take the server back into use, execute ' +
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|                                 '`clear server <server> maintenance`.')
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|                 .usage('Usage: drain server <server>')
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|         }, function(argv) {
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| 
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|             maxctrl(argv, function(host) {
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| 
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|                 var target = 'servers/' + argv.server
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|                 var path = 'data.relationships.services.data'
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|                 var timeout = argv['drain-timeout']
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| 
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|                 return doRequest(host, target, (res) => {
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|                     // Store the services, used later to add the server back into them
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|                     var services =_.get(res, path, [])
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| 
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|                     // Remove the relationships
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|                     _.set(res, path, [])
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| 
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|                     // Remove unneeded data
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|                     delete res.data.attributes
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| 
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|                     var addServersBack = () => {
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|                         _.set(res, path, services)
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|                         return doRequest(host, target, null, {method: 'PATCH', body: res})
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|                     }
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| 
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|                     return doRequest(host, target, null, {method: 'PATCH', body: res})
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|                         .then(() => waitUntilZero(host, target, 'data.attributes.statistics.connections', timeout))
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|                         .then(() => doRequest(host, target + '/set?state=maintenance', null, {method: 'PUT'}))
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|                         .then(addServersBack, addServersBack) // Try to add the servers back even if we receive an error
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|                 })
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|             })
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|         })
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|         .usage('Usage: drain <command>')
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|         .help()
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|         .command('*', 'the default command', {}, function(argv) {
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|             maxctrl(argv, function(host) {
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|                 return error('Unknown command. See output of `help drain` for a list of commands.')
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|             })
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|         })
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| }
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