unleash-server
Version:
Unleash is an enterprise ready feature flag service. It provides different strategies for handling feature flags.
67 lines • 2.78 kB
JavaScript
import EventEmitter from 'events';
export const UPDATE_REVISION = 'UPDATE_REVISION';
export default class ConfigurationRevisionService extends EventEmitter {
constructor({ eventStore }, { getLogger, flagResolver, }) {
super();
this.maxRevisionId = new Map();
this.logger = getLogger('configuration-revision-service.ts');
this.eventStore = eventStore;
this.flagResolver = flagResolver;
this.revisionId = 0;
}
static getInstance({ eventStore }, { getLogger, flagResolver, }) {
if (!ConfigurationRevisionService.instance) {
ConfigurationRevisionService.instance =
new ConfigurationRevisionService({ eventStore }, { getLogger, flagResolver });
}
return ConfigurationRevisionService.instance;
}
async getMaxRevisionId(environment) {
if (environment) {
let maxEnvRevisionId = this.maxRevisionId.get(environment) ?? 0;
if (maxEnvRevisionId === 0) {
maxEnvRevisionId =
await this.updateMaxEnvironmentRevisionId(environment);
}
if (maxEnvRevisionId > 0) {
return maxEnvRevisionId;
}
}
if (this.revisionId > 0) {
return this.revisionId;
}
else {
return this.updateMaxRevisionId();
}
}
async updateMaxEnvironmentRevisionId(environment) {
let maxRevId = this.maxRevisionId.get(environment) ?? 0;
const actualMax = await this.eventStore.getMaxRevisionId(maxRevId, environment);
if (maxRevId < actualMax) {
this.maxRevisionId.set(environment, actualMax);
maxRevId = actualMax;
}
return maxRevId;
}
async updateMaxRevisionId(emit = true) {
if (this.flagResolver.isEnabled('disableUpdateMaxRevisionId')) {
return 0;
}
const revisionId = await this.eventStore.getMaxRevisionId(this.revisionId);
if (this.revisionId !== revisionId) {
const knownEnvironments = [...this.maxRevisionId.keys()];
this.logger.debug(`Updating feature configuration with new revision Id ${revisionId} and all envs: ${knownEnvironments.join(', ')}`);
await Promise.allSettled(knownEnvironments.map((environment) => this.updateMaxEnvironmentRevisionId(environment)));
this.revisionId = revisionId;
if (emit) {
this.emit(UPDATE_REVISION, revisionId);
}
}
return this.revisionId;
}
destroy() {
ConfigurationRevisionService.instance?.removeAllListeners();
ConfigurationRevisionService.instance = undefined;
}
}
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