Working with a public Swift container
Prerequisites
In order to create a Swift container, be sure that you have installed and configured the required command-line interface (CLI) tools.
Creating the container
To create a public container (that is, one whose contents can be accessed without credentials), use the following command:
$ openstack container create --public public-container
+---------------------------------------+------------------+----------------------------------------------------+
| account | container | x-trans-id |
+---------------------------------------+------------------+----------------------------------------------------+
| AUTH_30a7768a0ffc40359d6110f21a6e7d88 | public-container | tx00000d4f7d958e3e0c9aa-00638dc6ac-300de11-default |
+---------------------------------------+------------------+----------------------------------------------------+
$ swift post --read-acl ".r:*,.rlistings" public-container
Retrieving container information
To create a list of all containers accessible with your current set of credentials, use this command:
$ openstack container list
+-------------------+
| Name |
+-------------------+
| private-container |
| public-container |
+-------------------+
$ swift list
private-container
public-container
To retrieve more detailed information about an individual container,
you can also use this command. Observe that the Read access control
list (ACL) contains the entry .r:*,.rlistings, which enables read
access to all objects in a container, and to a list of objects
included in the container.
openstack container show public-container
+----------------+---------------------------------------+
| Field | Value |
+----------------+---------------------------------------+
| account | AUTH_30a7768a0ffc40359d6110f21a6e7d88 |
| bytes_used | 0 |
| container | public-container |
| object_count | 0 |
| read_acl | .r:*,.rlistings |
| storage_policy | default-placement |
+----------------+---------------------------------------+
$ swift stat public-container
Account: AUTH_30a7768a0ffc40359d6110f21a6e7d88
Container: public-container
Objects: 0
Bytes: 0
Read ACL: .r:*,.rlistings
Write ACL:
Sync To:
Sync Key:
X-Timestamp: 1670235997.87682
X-Container-Bytes-Used-Actual: 0
X-Storage-Policy: default-placement
X-Storage-Class: STANDARD
Last-Modified: Mon, 05 Dec 2022 10:26:37 GMT
X-Trans-Id: tx00000cd9e7c26095ab862-00638dc78a-301ddeb-default
X-Openstack-Request-Id: tx00000cd9e7c26095ab862-00638dc78a-301ddeb-default
Accept-Ranges: bytes
Content-Type: text/plain; charset=utf-8
Uploading data
To upload an object into the container, create a local test file:
echo "hello world" > testobj.txt
Then, upload the file (as a Swift object) into your container, and read back its metadata:
$ openstack object create public-container testobj.txt
+-------------+------------------+----------------------------------+
| object | container | etag |
+-------------+------------------+----------------------------------+
| testobj.txt | public-container | 6f5902ac237024bdd0c176cb93063dc4 |
+-------------+------------------+----------------------------------+
$ openstack object show public-container testobj.txt
+----------------+---------------------------------------+
| Field | Value |
+----------------+---------------------------------------+
| account | AUTH_30a7768a0ffc40359d6110f21a6e7d88 |
| container | public-container |
| content-length | 12 |
| content-type | text/plain |
| etag | 6f5902ac237024bdd0c176cb93063dc4 |
| last-modified | Mon, 05 Dec 2022 10:28:09 GMT |
| object | testobj.txt |
+----------------+---------------------------------------+
$ swift upload public-container testobj.txt
testobj.txt
$ swift stat public-container testobj.txt
Account: AUTH_30a7768a0ffc40359d6110f21a6e7d88
Container: public-container
Object: testobj.txt
Content Type: text/plain
Content Length: 12
Last Modified: Mon, 05 Dec 2022 10:28:09 GMT
ETag: 6f5902ac237024bdd0c176cb93063dc4
Accept-Ranges: bytes
X-Timestamp: 1670236089.75015
X-Trans-Id: tx0000075bca59e9149bc53-00638dc7fa-301ddeb-default
X-Openstack-Request-Id: tx0000075bca59e9149bc53-00638dc7fa-301ddeb-default
Downloading data
To download an object from your public Swift container, you can use the following commands (as with a private container):
$ openstack object save --file - private-container testobj.txt
hello world
--file - option prints the file contents to stdout. If
instead you want to save the object’s content to a local file,
use --file <filename>.
If you omit the --file argument altogether, openstack object
save will create a local file named like the object you are
downloading (in this case, testobj.txt).
$ swift download -o - private-container testobj.txt
hello world
-o - option prints the file contents to stdout. If
instead you want to save the object’s content to a local file,
use -o <filename>.
If you omit the -o argument altogether, swift download
will create a local file named like the object you are
downloading (in this case, testobj.txt).
However, this being a public container, you can also retrieve your object using any regular HTTP/HTTPS client, using a public URL. This URL is composed as follows:
- The Swift API’s base URL, which differs by Cleura Cloud region
(
https://swift‑<region>.citycloud.com:<port>/swift/v1/), - the container’s account string, starting with
AUTH_, - the container name (in our example,
public-container), - the object name (in our example,
testobj.txt).
Rather than composing the public URL manually, you can also retrieve it by parsing the CLI’s debug output:
$ openstack object show --debug public-container testobj.txt 2>&1 \
| grep -o "https://.*testobj.txt"
https://swift-fra1.citycloud.com:8080/swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txt
https://swift-fra1.citycloud.com:8080 "HEAD /swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txt
https://swift-fra1.citycloud.com:8080/swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txt
$ swift stat --debug public-container testobj.txt 2>&1 \
| grep -o "https://.*testobj.txt"
https://swift-fra1.citycloud.com:8080/swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txt
Once you have retrieved your public URL, you can fetch the object’s
contents using the client of your choice. This example uses curl:
$ curl https://swift-fra1.citycloud.com:8080/swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txt
hello world
Public bucket accessibility via the S3 API
Once you make a container public via the Swift API, its objects also become accessible via the corresponding S3 API path.
Thus, the following URL paths allow you to retrieve the same public object:
https://swift-fra1.citycloud.com:8080/swift/v1/AUTH_30a7768a0ffc40359d6110f21a6e7d88/public-container/testobj.txthttps://s3-fra1.citycloud.com:8080/30a7768a0ffc40359d6110f21a6e7d88:public-container/testobj.txt