Downloading objects

Now that we have configured OpenStack Object Storage, we can also retrieve the stored objects using our swift client.

Getting ready

Ensure you are logged in to a Ubuntu host that has access to our OpenStack environment on the 192.168.100.0/24 public network. This host will be used to run client tools against the OpenStack environment created. If you are using the accompanying Vagrant environment, as described in the Preface, you can use the controller node. This has the python-swiftclient package installed that provides the swift command-line client.

If you created this node with Vagrant, you can execute the following command:

vagrant ssh controller

Ensure you have set the following credentials (adjust the path to your certificates and key file to match your environment if not using the Vagrant environment):

export OS_TENANT_NAME=cookbook
export OS_USERNAME=admin
export OS_PASSWORD=openstack
export OS_AUTH_URL=https://192.168.100.200:5000/v2.0/
export OS_NO_CACHE=1
export OS_KEY=/vagrant/cakey.pem
export OS_CACERT=/vagrant/ca.pem

How to do it...

We will download objects from our OpenStack Object Storage environment using different swift client options.

Downloading objects

To download the tmp/test/test1 object, we issue the following command:

swift download test tmp/test/test1

The preceding command downloads the object to our filesystem. As we downloaded a file with the full path, this directory structure is preserved. So, we end up with a new directory structure of tmp/test with a file called test1.

Downloading objects with the -o parameter

To download the file without preserving the file structure, or to simply rename it to something else, we specify the -o parameter:

swift download test tmp/test/test1 -o test1

Downloading all objects from a container

We can also download complete containers to our local filesystem. To do this, we simply specify the container we want to download:

swift download test

The preceding command will download all objects found under the test container.

Downloading all objects from our OpenStack Object Storage account

We can download all objects that reside under our OpenStack Object Storage account. If we have multiple containers, all objects from all containers will be downloaded. We do this with the --all parameter:

swift download --all

The preceding command will download all objects with full paths preceded by the container name, as shown here:

Downloading all objects from our OpenStack Object Storage account

How it works...

The swift client is a basic but versatile tool that allows us to do many of the things we want to do with files. You can download objects and containers using the following syntax:

swift download container_name {object … }

To download an object and rename the file on the local filesystem, we use the -o parameter to specify a different local filename:

swift download container_name object -o renamed_object

To download all objects from our account (for example, from all containers), we specify the following syntax:

swift download --all
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