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: 2022-01-01
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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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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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// 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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// Read and extract the value
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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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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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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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}, 2000)
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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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maxctrl(argv, function(host) {
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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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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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// Remove the relationships
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_.set(res, path, [])
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// Remove unneeded data
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delete res.data.attributes
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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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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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