Get collection usage size with ARM metrics call (#327)

- Removed `readCollectionQuotaInfo` call. The only data we need is the usage size which we can get via the ARM metrics call instead.
- Added `getCollectionUsageSize` which fetches the `DataUsage` and `IndexUsage` metrics, converts them to KB, and returns the sum as the total usage size

src/Common/dataAccess/getCollectionDataUsageSize.ts

@@ -0,0 +1,87 @@
+import { armRequest } from "../../Utils/arm/request";
+import { configContext } from "../../ConfigContext";
+import { handleError } from "../ErrorHandlingUtils";
+import { userContext } from "../../UserContext";
+
+interface TimeSeriesData {
+  data: {
+    timeStamp: string;
+    total: number;
+  }[];
+  metadatavalues: {
+    name: {
+      localizedValue: string;
+      value: string;
+    };
+    value: string;
+  };
+}
+
+interface MetricsData {
+  displayDescription: string;
+  errorCode: string;
+  id: string;
+  name: {
+    value: string;
+    localizedValue: string;
+  };
+  timeseries: TimeSeriesData[];
+  type: string;
+  unit: string;
+}
+
+interface MetricsResponse {
+  cost: number;
+  interval: string;
+  namespace: string;
+  resourceregion: string;
+  timespan: string;
+  value: MetricsData[];
+}
+
+export const getCollectionUsageSizeInKB = async (databaseName: string, containerName: string): Promise<number> => {
+  const subscriptionId = userContext.subscriptionId;
+  const resourceGroup = userContext.resourceGroup;
+  const accountName = userContext.databaseAccount.name;
+  const filter = `DatabaseName eq '${databaseName}' and CollectionName eq '${containerName}'`;
+  const metricNames = "DataUsage,IndexUsage";
+  const path = `/subscriptions/${subscriptionId}/resourceGroups/${resourceGroup}/providers/Microsoft.DocumentDB/databaseAccounts/${accountName}/providers/microsoft.insights/metrics`;
+
+  try {
+    const metricsResponse: MetricsResponse = await armRequest({
+      host: configContext.ARM_ENDPOINT,
+      path,
+      method: "GET",
+      apiVersion: "2018-01-01",
+      queryParams: {
+        filter,
+        metricNames
+      }
+    });
+
+    if (metricsResponse?.value?.length !== 2) {
+      return undefined;
+    }
+
+    const dataUsageData: MetricsData = metricsResponse.value[0];
+    const indexUsagedata: MetricsData = metricsResponse.value[1];
+    const dataUsageSizeInKb: number = getUsageSizeInKb(dataUsageData);
+    const indexUsageSizeInKb: number = getUsageSizeInKb(indexUsagedata);
+
+    return dataUsageSizeInKb + indexUsageSizeInKb;
+  } catch (error) {
+    handleError(error, "getCollectionUsageSize");
+    throw error;
+  }
+};
+
+const getUsageSizeInKb = (metricsData: MetricsData): number => {
+  if (metricsData?.errorCode !== "Success") {
+    throw Error(`Get collection usage size failed: ${metricsData.errorCode}`);
+  }
+
+  const timeSeriesData: TimeSeriesData = metricsData?.timeseries?.[0];
+  const usageSizeInBytes: number = timeSeriesData?.data?.[0]?.total;
+
+  return usageSizeInBytes ? usageSizeInBytes / 1024 : 0;
+};