def getS3Object()

in scripts/cp4s_install.py [0:0]
20 lines of code
5 McCabe index (conditional complexity)

    def getS3Object(self, bucket=None, s3Path=None, destPath=None):
        """
        Return destPath which is the local file path provided as the destination of the download.
        
        A pre-signed URL is created and used to download the object from the given S3 bucket
        with the given S3 key (s3Path) to the given local file system destination (destPath).
        
        The destination path is assumed to be a full path to the target destination for 
        the object. 
        
        If the directory of the destPath does not exist it is created.
        It is assumed the objects to be gotten are large binary objects.
        
        For details on how to download a large file with the requests package see:
        https://stackoverflow.com/questions/16694907/how-to-download-large-file-in-python-with-requests-py
        """
        methodName = "getS3Object"
        
        if (not bucket):
            raise MissingArgumentException("An S3 bucket name (bucket) must be provided.")
        #endIf
        
        if (not s3Path):
            raise MissingArgumentException("An S3 object key (s3Path) must be provided.")
        #endIf
        
        if (not destPath):
            raise MissingArgumentException("A file destination path (destPath) must be provided.")
        #endIf
        
        TR.info(methodName, "STARTED download of object: %s from bucket: %s, to: %s" % (s3Path,bucket,destPath))
        
        s3url = self.s3.generate_presigned_url(ClientMethod='get_object',Params={'Bucket': bucket, 'Key': s3Path},ExpiresIn=60)
        TR.fine(methodName,"Getting S3 object with pre-signed URL: %s" % s3url)
        #endIf
        
        destDir = os.path.dirname(destPath)
        if (not os.path.exists(destDir)):
            os.makedirs(destDir)
        TR.info(methodName,"Created object destination directory: %s" % destDir)
        #endIf
        
        r = requests.get(s3url, stream=True)
        with open(destPath, 'wb') as destFile:
            shutil.copyfileobj(r.raw, destFile)
        #endWith

        TR.info(methodName, "COMPLETED download from bucket: %s, object: %s, to: %s" % (bucket,s3Path,destPath))
        
        return destPath