332 lines
6.8 KiB
JavaScript
332 lines
6.8 KiB
JavaScript
const debounce = require('debounce');
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// TODO support multiple instances of the same service name
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function sameTags(a, b)
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{
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if (a.length != b.length)
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return false;
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for (let i = 0, l = a.length; i < l; i++)
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{
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if (!b.includes(a[i]))
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return false;
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}
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return true;
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}
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class ConsulCatalog
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{
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constructor(logger, config)
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{
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const self = this;
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self.rawData = null;
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// Always use promises, the code relies on it
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config.consul.promisify = true;
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self._config = config;
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self._logger = logger;
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self._consul = require('consul')(config.consul);
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self._services = [];
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self._updating = false;
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self._requireUpdate = false;
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self._debouncedUpdate = null;
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this._logger.info('Starting watch for catalog service list');
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self._watch = self._consul.watch({
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method: self._consul.catalog.service.list,
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options: {}
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});
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self._watch.on('change', (data, res) =>
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{
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if (self._applyCatalogData(data))
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self._doUpdate();
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});
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self._watch.on('error', err =>
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{
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// TODO better exception handling
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self._logger.error('Error while watching catalog service list', err);
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});
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}
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get services()
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{
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return this._services;
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}
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serviceByName(name)
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{
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return this._services.find(service => service.name == name) || null;
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}
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servicesByTag(tag)
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{
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return this._services.filter(service => service.tags.includes(tag));
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}
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servicesByTags(tags)
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{
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return this._services.filter(service => tags.every(tag => service.tags.includes(tag)));
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}
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_applyCatalogData(data)
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{
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const self = this;
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self.rawData = data;
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let changed = false;
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// Remove services that no longer exist
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const serviceNames = Object.keys(data);
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self._services = self._services.filter(service =>
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{
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const serviceIndex = serviceNames.indexOf(service.name);
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if (serviceIndex == -1)
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{
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// Previously detected service no longer appears in Consul, remove
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// any watches that may be present and remove it from the list
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service._delete();
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changed = true;
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return false;
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}
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if (service._applyCatalogData(data[service.name]))
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changed = true;
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// Remove from serviceNames to indicate it has already been applied
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serviceNames.splice(serviceIndex, 1);
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return true;
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});
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// All remaining entries in serviceNames are new
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serviceNames.forEach(name =>
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{
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self._logger.debug(`Found new service: ${name}`)
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self._services.push(new ConsulService(self, name, data[name]));
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changed = true;
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});
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return changed;
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}
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_doUpdate()
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{
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const self = this;
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if (self._updating)
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{
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self._logger.debug('Update already running, will re-run after it is finished');
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self._requireUpdate = true;
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return;
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}
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if (self._debouncedUpdate == null)
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{
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self._debouncedUpdate = debounce(() =>
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{
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self._updating = true;
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self._requireUpdate = false;
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self._logger.info('Running update handlers');
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const handlerPromises = [];
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self._config.onUpdate.forEach(handler =>
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{
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const handlerPromise = Promise.resolve(handler(self, self._logger));
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handlerPromises.push(handlerPromise);
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});
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Promise.all(handlerPromises)
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.then(() =>
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{
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self._logger.info('Running after-update handler');
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Promise.resolve(self._config.afterUpdate(self, self._logger))
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.then(() =>
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{
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self._logger.info('Update completed');
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self._updating = false;
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if (self._requireUpdate)
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{
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self._logger.debug('Update re-run requested');
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self._doUpdate();
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}
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});
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});
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}, 500);
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}
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self._debouncedUpdate();
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}
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}
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class ConsulService
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{
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constructor(catalog, name, tags)
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{
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this._catalog = catalog;
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this._consul = catalog._consul;
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this._logger = catalog._logger;
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this._watch = null;
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this._rawData = null;
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this._rawDataPromise = null;
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this.name = name;
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this.tags = tags;
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}
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async getAddress()
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{
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var rawData;
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try
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{
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rawData = await this._getRawData();
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}
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catch(e)
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{
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// TODO better exception handling
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this._logger.error('Error while retrieving service status', err);
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return null;
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}
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if (rawData.length == 0)
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return null;
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if (rawData[0].Service.Address != '')
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return rawData[0].Service.Address;
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return rawData[0].Node.Address;
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}
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async getPort()
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{
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var rawData;
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try
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{
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rawData = await this._getRawData();
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}
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catch(e)
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{
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// TODO better exception handling
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this._logger.error('Error while retrieving service status', err);
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return null;
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}
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return rawData.length > 0 ? rawData[0].Service.Port : null;
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}
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// TODO getHealth
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_getRawData()
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{
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const self = this;
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if (self._rawDataPromise !== null)
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return self._rawDataPromise;
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// Get status information for the service and start watching it
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self._rawDataPromise = new Promise((resolve, reject) =>
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{
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let firstResponse = true;
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self._logger.debug(`Starting watch for service: ${this.name}`);
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self._watch = self._consul.watch({
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method: self._consul.health.service,
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options: { service: self.name }
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});
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self._watch.on('change', (data, res) =>
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{
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if (self._applyHealthData(data))
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self._catalog._doUpdate();
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if (firstResponse)
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{
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firstResponse = false;
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resolve(self._rawData);
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}
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});
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self._watch.on('error', err =>
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{
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// TODO better error handling
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self._logger.error(`Error while watching status for service: ${this.name}`, err);
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if (firstResponse)
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{
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firstResponse = false;
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reject(err);
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}
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// Try again the next time
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self._rawDataPromise = null;
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});
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});
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return self._rawDataPromise;
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}
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_delete()
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{
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if (this._watch !== null)
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{
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this._logger.debug(`Stopping watch for service: ${this.name}`);
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this._watch.end();
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}
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}
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_applyCatalogData(data)
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{
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if (sameTags(this.tags, data))
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return false;
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this._logger.info(`${this.name}: tags changed from ${JSON.stringify(this.tags)} to ${JSON.stringify(data)}`);
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this.tags = data;
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return true;
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}
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_applyHealthData(data)
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{
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if (data == this._rawData)
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return false;
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const isUpdate = this._rawData != null;
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this._rawData = data;
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// If this is the first time we've received data, it is guaranteed to be the result of
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// an update handler requesting this data and the handlers do not need to be called again.
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return isUpdate;
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}
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}
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module.exports = ConsulCatalog; |