feat: streaming and polling deltas #712
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| @@ -401,13 +439,18 @@ Message: ${err.message}`, | |||
| } else if (res.ok) { | |||
| nextFetch = this.countSuccess(); | |||
| try { | |||
| const data: ClientFeaturesResponse = await res.json(); | |||
| const data = await res.json(); | |||
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it can be either full response type or delta type
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| export const SUPPORTED_SPEC_VERSION = '4.3.0'; | ||
| export const SUPPORTED_SPEC_VERSION = '5.2.0'; |
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this hasn't been updated for a while
| } else { | ||
| this.initialEventSourceConnected = true; | ||
| } | ||
| this.handleFlagsFromStream(event); |
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in streaming mode we always rely 100% on streaming. previously first request in streaming was a polling request
| @@ -97,7 +105,7 @@ export default class Repository extends EventEmitter implements EventEmitter { | |||
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| private eventSource: EventSource | undefined; | |||
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| private initialEventSourceConnected: boolean = false; | |||
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no need to check if first connection is different from another since all streaming goes with SSEs
| } catch (err) { | ||
| this.emit(UnleashEvents.Error, err); | ||
| } | ||
| } | ||
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| timedFetch(interval: number) { | ||
| if (interval > 0 && !this.eventSource) { | ||
| if (interval > 0 && this.mode.type === 'polling') { |
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we added explicit mode in the constructor params since we need more than eventSource (mode + format)
| @@ -192,7 +197,11 @@ export default class Repository extends EventEmitter implements EventEmitter { | |||
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| async start(): Promise<void> { | |||
| // the first fetch is used as a fallback even when streaming is enabled | |||
| await Promise.all([this.fetch(), this.loadBackup(), this.loadBootstrap()]); | |||
| await Promise.all([ | |||
| this.mode.type === 'streaming' ? Promise.resolve() : this.fetch(), | |||
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no need to fetch data on startup with HTTP call when streaming is enabled
| }); | ||
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| this.setReady(); | ||
| this.emit(UnleashEvents.Changed, Object.values(this.data)); |
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decided not to introduce new event in this PR. We may consider ChangedDelta later on
| @@ -379,7 +417,7 @@ Message: ${err.message}`, | |||
| if (this.tags) { | |||
| mergedTags = this.mergeTagsToStringArray(this.tags); | |||
| } | |||
| const url = getUrl(this.url, this.projectName, this.namePrefix, mergedTags); | |||
| const url = getUrl(this.url, this.projectName, this.namePrefix, mergedTags, this.mode); | |||
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fetch call need to be conditional
| ): string => { | ||
| const url = resolveUrl(base, './client/features'); | ||
| const isDeltaPolling = mode && mode.type === 'polling' && mode.format === 'delta'; | ||
| const url = resolveUrl(base, isDeltaPolling ? './client/delta' : './client/features'); |
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delta has to be opt in
| @@ -76,7 +76,7 @@ export class Unleash extends EventEmitter { | |||
| storageProvider, | |||
| disableAutoStart = false, | |||
| skipInstanceCountWarning = false, | |||
| experimentalMode = { type: 'polling' }, | |||
| experimentalMode = { type: 'polling', format: 'full' }, | |||
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by default keep doing what we have been doing so far
About the changes
Delta support for streaming and polling.
Our Mode type shows what options are possible
Mode = { type: 'polling'; format: 'delta' | 'full' } | { type: 'streaming' };. In streaming you have no choice and deltas is your only options. In polling mode you can choose and we default to full format.Important files
Discussion points