export async function readExport()

in src/qldb/JournalS3ExportReader.ts [126:176]
44 lines of code
2 McCabe index (conditional complexity)

export async function readExport(
    describeJournalExportResult: JournalS3ExportDescription,
    s3Client: S3
): Promise<JournalBlock[]> {
    const exportConfiguration: S3ExportConfiguration = describeJournalExportResult.S3ExportConfiguration;
    const prefix: string = exportConfiguration.Prefix;
    const bucketName: string = exportConfiguration.Bucket;
    const request: ListObjectsV2Request = {
        Bucket: bucketName,
        Prefix: prefix
    };
    const response: ListObjectsV2Output = await s3Client.listObjectsV2(request).promise();
    const objects: ObjectList = response.Contents;
    log("Found the following objects for list from S3:");
    objects.forEach(function(object) {
        log(object.Key);
    });

    // Validate initial manifest file was written.
    const expectedManifestKey: string = (`${prefix}${describeJournalExportResult.ExportId}.started.manifest`);
    const initialManifest: string = filterForInitialManifest(objects, expectedManifestKey);
    log(`Found the initial manifest with key: ${initialManifest}.`);

    // Find the final manifest file, it should contain the exportId in it.
    const completedManifestFileKey: string = filterForCompletedManifest(objects);
    let getObjectRequest: GetObjectRequest = {
        Bucket: bucketName,
        Key: completedManifestFileKey
    };
    const completedManifestObject: string = (await s3Client.getObject(getObjectRequest).promise()).Body.toString();
    const dataFileKeys: string[] = getDataFileKeysFromManifest(completedManifestObject);

    log(`Found the following keys in the manifest files: ${JSON.stringify(dataFileKeys)}`);
    const journalBlocks: JournalBlock[] = [];
    
    for (const dataFileKey of dataFileKeys) {
        log(`Reading file with S3 key ${dataFileKey} from bucket: ${bucketName}`);
        getObjectRequest = {
            Bucket: bucketName,
            Key: dataFileKey
        };
        const s3Object: string = (await s3Client.getObject(getObjectRequest).promise()).Body.toString();
        const blocks: JournalBlock[] = getJournalBlocks(s3Object);

        compareKeyWithContentRange(dataFileKey, blocks[0], blocks[blocks.length-1]);
        blocks.forEach(function(block) {
            journalBlocks.push(block);
        });
    }
    return journalBlocks;
}