Google Cloud Storage(Python): How to check when was file last modified?

Question

We have a job that checks if a file on the cloud storage has been modified. If so, then it reads the data from the file and processes it further.

I want to know if there is an API to check when a file on the cloud storage was last modified.

Answer 1

You can now do this using the official Python lib for Google Storage.

from google.cloud import storage


def blob_metadata(bucket_name, blob_name):
    """Prints out a blob's metadata."""
    # bucket_name = 'your-bucket-name'
    # blob_name = 'your-object-name'

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)
    blob = bucket.get_blob(blob_name)

    print("Blob: {}".format(blob.name))
    print("Bucket: {}".format(blob.bucket.name))
    print("Storage class: {}".format(blob.storage_class))
    print("ID: {}".format(blob.id))
    print("Size: {} bytes".format(blob.size))
    print("Updated: {}".format(blob.updated))
    print("Generation: {}".format(blob.generation))
    print("Metageneration: {}".format(blob.metageneration))
    print("Etag: {}".format(blob.etag))
    print("Owner: {}".format(blob.owner))
    print("Component count: {}".format(blob.component_count))
    print("Crc32c: {}".format(blob.crc32c))
    print("md5_hash: {}".format(blob.md5_hash))
    print("Cache-control: {}".format(blob.cache_control))
    print("Content-type: {}".format(blob.content_type))
    print("Content-disposition: {}".format(blob.content_disposition))
    print("Content-encoding: {}".format(blob.content_encoding))
    print("Content-language: {}".format(blob.content_language))
    print("Metadata: {}".format(blob.metadata))
    print("Temporary hold: ", "enabled" if blob.temporary_hold else "disabled")
    print(
        "Event based hold: ",
        "enabled" if blob.event_based_hold else "disabled",
    )
    if blob.retention_expiration_time:
        print(
            "retentionExpirationTime: {}".format(
                blob.retention_expiration_time
            )
        )

In your case you will have to look at blob.updated property

Answer 2

You can do this with boto:

>>> import boto
>>> conn = boto.connect_gs()
>>> bucket = conn.get_bucket('yourbucket')
>>> k = bucket.get_key('yourkey')
>>> k.last_modified
'Tue, 04 Dec 2012 17:44:57 GMT'

There is also an App Engine Python interface to cloud storage, but I don't think it exposes the metadata you want.