@azure/cosmos
Version:
Microsoft Azure Cosmos DB Service Node.js SDK for NOSQL API
151 lines • 6.77 kB
JavaScript
import { ChangeFeedIteratorResponse } from "./ChangeFeedIteratorResponse.js";
import { Constants, copyObject, ResourceType, StatusCodes } from "../../common/index.js";
import { ErrorResponse } from "../../request/index.js";
import { ContinuationTokenForPartitionKey } from "./ContinuationTokenForPartitionKey.js";
import { convertToInternalPartitionKey } from "../../documents/index.js";
import { getEmptyCosmosDiagnostics, withDiagnostics } from "../../utils/diagnostics.js";
import { buildFeedOptions, decryptChangeFeedResponse } from "./changeFeedUtils.js";
import { computePartitionKeyRangeId } from "../ClientUtils.js";
/**
* @hidden
* Provides iterator for change feed for one partition key.
*
* Use `Items.getChangeFeedIterator()` to get an instance of the iterator.
*/
export class ChangeFeedForPartitionKey {
clientContext;
container;
resourceId;
resourceLink;
partitionKey;
changeFeedOptions;
continuationToken;
startTime;
rId;
isInstantiated;
startFromNow;
/**
* @internal
*/
constructor(clientContext, container, resourceId, resourceLink, partitionKey, changeFeedOptions) {
this.clientContext = clientContext;
this.container = container;
this.resourceId = resourceId;
this.resourceLink = resourceLink;
this.partitionKey = partitionKey;
this.changeFeedOptions = changeFeedOptions;
this.continuationToken = changeFeedOptions.continuationToken
? JSON.parse(changeFeedOptions.continuationToken)
: undefined;
this.isInstantiated = false;
// startTime is used to store and specify time from which change feed should start reading new changes. StartFromNow flag is used to indicate fetching changes from now.
if (changeFeedOptions.startFromNow) {
this.startFromNow = true;
}
else if (changeFeedOptions.startTime) {
this.startTime = changeFeedOptions.startTime.toUTCString();
}
}
async instantiateIterator(diagnosticNode) {
await this.setIteratorRid(diagnosticNode);
if (this.clientContext.enableEncryption) {
await this.container.checkAndInitializeEncryption();
// returns copy of object to avoid encryption of original partition key passed
this.partitionKey = copyObject(this.partitionKey);
diagnosticNode.beginEncryptionDiagnostics(Constants.Encryption.DiagnosticsEncryptOperation);
const { partitionKeyList, encryptedCount } = await this.container.encryptionProcessor.getEncryptedPartitionKeyValue(convertToInternalPartitionKey(this.partitionKey));
this.partitionKey = partitionKeyList;
diagnosticNode.endEncryptionDiagnostics(Constants.Encryption.DiagnosticsEncryptOperation, encryptedCount);
}
if (this.continuationToken) {
if (!this.continuationTokenRidMatchContainerRid()) {
throw new ErrorResponse("The continuation is not for the current container definition.");
}
}
else {
this.continuationToken = new ContinuationTokenForPartitionKey(this.rId, this.partitionKey, "");
}
this.isInstantiated = true;
}
continuationTokenRidMatchContainerRid() {
if (this.continuationToken.rid !== this.rId) {
return false;
}
return true;
}
async setIteratorRid(diagnosticNode) {
const { resource } = await this.container.readInternal(diagnosticNode);
this.rId = resource._rid;
}
/**
* Change feed is an infinite feed. hasMoreResults is always true.
*/
get hasMoreResults() {
return true;
}
/**
* Gets an async iterator which will yield change feed results.
*/
async *getAsyncIterator() {
do {
const result = await this.readNext();
yield result;
} while (this.hasMoreResults);
}
/**
* Returns the result of change feed from Azure Cosmos DB.
*/
async readNext() {
return withDiagnostics(async (diagnosticNode) => {
if (!this.isInstantiated) {
await this.instantiateIterator(diagnosticNode);
}
const result = await this.fetchNext(diagnosticNode);
if (result.statusCode === StatusCodes.Ok) {
if (this.clientContext.enableEncryption) {
await decryptChangeFeedResponse(result, diagnosticNode, this.changeFeedOptions.changeFeedMode, this.container.encryptionProcessor);
}
}
return result;
}, this.clientContext);
}
/**
* Read feed and retrieves the next set of results in Azure Cosmos DB.
*/
async fetchNext(diagnosticNode) {
const response = await this.getFeedResponse(diagnosticNode);
this.continuationToken.Continuation = response.headers[Constants.HttpHeaders.ETag];
response.headers[Constants.HttpHeaders.ContinuationToken] = JSON.stringify(this.continuationToken);
return response;
}
async getFeedResponse(diagnosticNode) {
const feedOptions = buildFeedOptions(this.changeFeedOptions, this.continuationToken?.Continuation, this.startFromNow, this.startTime);
if (this.clientContext.enableEncryption) {
feedOptions.containerRid = this.container._rid;
}
try {
const isPartitionLevelFailOverEnabled = this.clientContext.isPartitionLevelFailOverEnabled();
const partitionKeyRangeId = await computePartitionKeyRangeId(diagnosticNode, convertToInternalPartitionKey(this.partitionKey), this.clientContext.partitionKeyRangeCache, isPartitionLevelFailOverEnabled, this.container);
const response = await this.clientContext.queryFeed({
path: this.resourceLink,
resourceType: ResourceType.item,
resourceId: this.resourceId,
resultFn: (result) => (result ? result.Documents : []),
diagnosticNode,
query: undefined,
options: feedOptions,
partitionKey: this.partitionKey,
partitionKeyRangeId,
});
return new ChangeFeedIteratorResponse(response.result, response.result ? response.result.length : 0, response.code, response.headers, getEmptyCosmosDiagnostics());
}
catch (err) {
// If any errors are encountered, throw the error.
const errorResponse = new ErrorResponse(err.message);
errorResponse.code = err.code;
errorResponse.headers = err.headers;
throw errorResponse;
}
}
}
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