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RadosGW client for Ceph S3 storage

Project description

radula is a small utility to add some friendliness to RadosGW for our team working with Ceph for S3-like storage. Little more than a wrapper for boto radula saves us time and headache by using nice defaults.

The primary functions for the current version are

  • Inspect radosgw bucket/key ACLs

  • Spot differences between bucket and key ACLs

  • Allow or disallow user read/write to buckets and keys

  • When modifying a bucket ACL, modify the ACLs for keys as well

  • Verify uploads using checksums

  • Upload using multiple threads

The name, “radula”, is a cephalopod-related term that hit close to RADOS. It’s not a tongue, or really even teeth; it’s more like if your tongue had teeth. Spooky.


Install radula from pypi using pip.

pip install radula

The radula command should be available in your $PATH.


Install the pip packages listed in testing-requirements.txt and run nosetests.

$ pip install -U -r testing-requirements.txt
$ nosetests --with-coverage --cover-package=radula

The effort to increase code coverage is ongoing.


radula uses boto, so all configuration is really boto configuration, with some extensions to support streaming copy operations, see the Streaming Copy section below for those custom items. Notable changes are replacing the url to amazon aws with that of one of your gateways. Where applicable, you may have to disable SSL as a default option.

# example shared /etc/boto.cfg
host =

is_secure = False

To add your personal credentials, fill in the following in ~/.boto:

aws_access_key_id = abcdef...
aws_secret_access_key = 0123456...

[profile other_role]
aws_access_key_id = wxyz...
aws_secret_access_key = 9765432...


The command structure for radula is radula [flags] command subject [target]. The “subject” matter or “target” of a request could be a local resource or a remote one, depending on the command being executed. These could be read as “source” and “destination” in some cases, but the intent is simply to flow left to right.

$ usage: radula [-h] [--version] [-r] [-w] [-t THREADS] [-p PROFILE]
          [-d DESTINATION] [-f] [-y] [-c CHUNK_SIZE] [-l] [-L LOG_LEVEL]
          [-n] [-z] [-e]
              [subject] [target] ...

RadosGW client

positional arguments:
  } command
  subject               Subject
  target                Target
  remainder             Additional targets for supporting commands. See README

      optional arguments:
        -h, --help            show this help message and exit
        --version             Prints version number
        -r, --read            During a user grant, permission includes reads
        -w, --write           During a user grant, permission includes writes
        -t THREADS, --threads THREADS
                              Number of threads to use for uploads. Default=3
        -p PROFILE, --profile PROFILE
                              Boto profile. Overrides AWS_PROFILE environment var
        -d DESTINATION, --destination DESTINATION
                              Destination boto profile, required for streaming copy
        -f, --force           Overwrite local files without confirmation
        -y, --verify          Verify uploads after they complete. Uses --threads
        -c CHUNK_SIZE, --chunk CHUNK_SIZE
                              multipart upload chunk size in bytes.
        -l, --long-keys       prepends bucketname to key results.
        -n, --dry-run         Print would-be deletions without deleting
        -z, --resume          Resume uploads if needed.
        -e, --encrypt         Store content encrypted at rest


This is a quick walkthrough of the features so far. In these scenarios, we acting as the user bibby, who owns the rados bucket mybucket. In some of the examples, we’ll be manipulating the access to this bucket for a second user called fred.

Contained in the bucket are two regular files: hello and world.

List available profiles

See Boto docs for working with profiles.

[bibby@machine ~]$ radula profiles

Displaying bucket ACL

[bibby@machine ~]$ radula get-acl mybucket
ACL for bucket: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL

The command get-acl prints the acl. radula assumed that the term mybucket was a bucket, being that it was a lone term.

Displaying key ACL

[bibby@machine ~]$ radula get-acl mybucket/hello
ACL for key: mybucket/hello
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL

Because the term contained a slash, the subject is correctly identified as hello within the bucket mybucket.

Comparing ACLs - Keys in bucket

[bibby@machine ~]$ radula compare-acl mybucket
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL

Keys with identical ACL: 2
Keys with different ACL: 0

The compare-acl command on a bucket will report of the sameness of ACLs across the keys as compared to the bucket. We’ll see this again later in another example.

This can be run against one key, limiting the compared objects to the one key against its bucket

[bibby@machine ~]$ radula check-acl mybucket/hello
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL

Keys with identical ACL: 1
Keys with different ACL: 0

Set a canned ACL

Can set the ACL of a bucket or key to one of the four AWS “canned” policies using set-acl. In this scenario, the subject can be a bucket or a key, with the target being a canned policy name.

[bibby@machine ~]$ radula set-acl mybucket/hello public-read
<< prints the output of get-acl after completing the operation

Changing the ACL on a bucket will will be applied to the keys as well, potentially overwriting any custom access given to keys. Run compare-acl before setting the bucket ACL to discover any special differences, as they may need to be recreated after the set-acl operation completes.

Sync ACLs

Should a difference of ACL had appeared, we could forcefully replace all key ACLs with the bucket’s ACL using sync-acl.

[bibby@machine ~]$ radula sync-acl mybucket
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL

Setting bucket's ACL on hello
Setting bucket's ACL on world

This is a PUT command, so it doesn’t bother to look at the current ACL for the keys; it just puts a copy of the bucket’s own ACL.

sync-acl can be done on a single key as well.

[bibby@machine ~]$ radula sync-acl mybucket/world
Setting bucket's ACL on world

Granting access to a key

To grant access to another user, we’ll make use of some new flags. -r and/or -w to indicate read and write. A grant may have one or both of rw. If both are absent, read is assumed. Permissions are separate, so it is possible to have a write-only grant.

For permission grants the subject is the user (as far as the usage format in the help text goes), and the target is the key or bucket.

[bibby@machine ~]$ radula allow fred mybucket/hello
granting READ to fred on key hello

Multiple grants to the same user for the same permission are possible in rados and on s3, but radula will guard against that and ignore the duplicate entry. Here, we’ll add “read-write”:

[bibby@machine ~]$ radula -wr allow fred mybucket/hello
User fred already has READ for key hello, skipping
granting WRITE to fred on key hello

Granting access to a bucket

Granting access to a bucket works the same way.
When a bucket ACL is modified, so are all of its keys. That action is really the whole purpose behind radula.
[bibby@machine ~]$ radula -wr allow fred mybucket
granting READ to fred on bucket mybucket
granting WRITE to fred on bucket mybucket
User fred already has READ for key <Key: mybucket,hello>, skipping
User fred already has WRITE for key <Key: mybucket,hello>, skipping
granting READ to fred on key <Key: mybucket,world>
granting WRITE to fred on key <Key: mybucket,world>

With both allow and disallow, if an ACL difference exists between the bucket and a key, that difference may still exist after the modification. With these commands, we aren’t syncing a modified bucket ACL down to the keys; we’re applying the same singular change to each target individually.

Disallow (buckets and keys)

Removing permissions works similarly to granting access, but with some differences. One assumption is about the omission of the read-write flags; If neither are present, both permissions are removed.













ACLs for the keys are modified first. The user’s access cannot be taken away from the bucket if it still exists for one of its keys, so the changes take place from bottom up.

Creating an difference and syncing down

Starting with a blank slate:

[bibby@machine ~]$ radula -wr disallow fred mybucket
No change for <Key: mybucket,hello>
No change for <Key: mybucket,world>
No change for mybucket

Give fred read on the bucket

[bibby@machine ~]$ radula -r allow fred mybucket
granting READ to fred on bucket mybucket
granting READ to fred on key <Key: mybucket,hello>
granting READ to fred on key <Key: mybucket,world>

Give fred write on one key

[bibby@machine ~]$ radula -w allow fred mybucket/world
granting WRITE to fred on key world

Confirm the difference..

[bibby@machine ~]$ radula compare-acl mybucket
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL
[CanonicalUser] Fred Fredricks = READ

Difference in world:
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL
[CanonicalUser] Fred Fredricks = READ
[CanonicalUser] Fred Fredricks = WRITE

Keys with identical ACL: 1
Keys with different ACL: 1

Plow the keys with the bucket’s settings.

[bibby@machine ~]$ radula sync-acl mybucket
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL
[CanonicalUser] Fred Fredricks = READ

Setting bucket's ACL on hello
Setting bucket's ACL on world

[bibby@machine ~]$ radula check-acl mybucket
Bucket ACL for: mybucket
[CanonicalUser:OWNER] Andrew Bibby = FULL_CONTROL
[CanonicalUser] Fred Fredricks = READ

Keys with identical ACL: 2
Keys with different ACL: 0

Upload and Download

These functions are similar for moving files in and out of the radosgw. Its intention is not to replace better tools like s3cmd, but rather to cover some very common use cases so that the installation and configuration of additional libraries might not be needed.

put, up, upload

The commands put, up, and upload are equivalent. For these examples, I’ve chosen to use up.

The syntax is radula up {source} {target}, where source is a local file or a glob. The target is a in radosgw path, and its behavior depends on the singularity or plurality of the source given.

If the target path ends with a slash (/), then the key is presumed to be the basename of the object appended at that path. See table below.

If multiple source files are given, the key will always assume it is part of a path, making an ending slash wholly optional.

When using globs, it’s important to know that the argument must be quoted to avoid shell expansion. For example to upload all files starting with the letter a from path, the command would be

radula up 'path/a*' bucket/path


















bucket/named/file, bucket/named/file2



bucket/named/file, bucket/named/file2

For faster multipart uploads, the default number of threads used is 3, but this can be set during upload using the -t option.

# upload a large file using 16 threads
radula -t 16 up large_file bucket

Upload verification via checksum can be enabled by adding the -y, --verify flag.

As of radula v0.6.6, uploads to a remote key that already exists will abort if -f, –force is not also given. The reason is to guard against accidentally loss of data in ceph.

Should portions of a multipart upload fail, there is a chance that it can be resumed. A reattempt at upload should abort citing the presence of a lingering multipart upload in progress. The multipart-list command should confirm as much. Adding the -z,--resume flag to the original upload command will inspect the uploaded parts and upload those that are absent or differ in checksum. The resume will be slower for each part, as the local parts are hashed and compared to the uploaded parts. Adding a verification step with -y,--verify is recommended.

# an upload resumation with verification
radula -t 16 -zy up large_file bucket

get, dl, download

The commands get, dl, and downlaod are equivalent. For these examples, I’ve chosen to use dl.

The the syntax is radula dl {source} [{target}]. The target is optional, and will default to the basename of the remote file to be stored in the current working directory.

Unlike up, the download commands do not support globs.















No attempt is made to create local paths that do not exist prior to download; in the table above dir is an existing directory.

If a file with the target name already exists, radula will ask if you wish to overwrite it unless the -f, --force flag is enabled.

As of radula v0.6.6, downloads are multi-threaded using 10 processes by default, which can be controlled with the -t, --threads flag. This is known to have issues writing to glusterfs, so -t 1 is recommended in that instance.

In radula v0.7.1, default threads was reduced to 3.

As of radula v0.7.9, uploads may include the -e,--encrypt flag to instruct Rados to store the data encrypted at rest, using its own internal mechanisms. When encrypted data is copied to another cluster, the remote copy should take on this setting without explicitly being told to.


An alternative to download is cat, which prints the contents of a remote subject to stdout.

$ echo "Hello there you" > hello
$ radula up hello mybucket/hello
INFO:radula:Finished uploading 16.00 B in 0.08s (188.82 Bps)
$ radula cat mybucket/hello
Hello there you

In radula 0.7+, cat accept the -c,`–chunk-size` parameter to print part of the remote file. Unique to this command is that the chunk param can be a range of integers or humanized units. If humanized units (ie, 2kb) are used, they’ll be converted into integer to conform with the [HTTP Range header spec](

When using a range query, the end of the range may be omitted to include everything from the starting position to the end of the file.

Omitting the first argument is not supported. Starting a range with zero (0-n) does work, but it is recommended to simply provide n by itself, because the range in inclusive. The range 0-100 would output 101 bytes, while input 100 returns 100.

A ValueError will be raised if end of the range is before the starting position.

# first two bytes
$ radula -c 2 cat mybucket/hello

# 2 bytes in until the end
$ radula -c '2-' cat mybucket/hello

# first byte to second byte (inclusive)
$ radula -c '1-2' cat mybucket/hello

verify uploads

Checksums can be obtained using local-md5 and remote-md5, and easily compared with verify.

The local-md5 command expects one local file argument, and will generate the same hash that is expected to be found on the remote. Multipart upload size matters, so the output hash may differ if uploaded by another mechanism.

The remote-md5 command expects one remote file uri, ie mybucket/path/myfile. It will return the etag attribute associated with the key, which will typically be a file md5 or conglomeration of multipart upload hashs with a number tacked at the end.

Calling verify [local_file] [remote_file] simply runs the operations mentioned above and tests their outputs for likeness.

To view raw metadata about a remote target, use info [remote_file]. The output will contain the etag and other data in JSON format. For quick access to size and hash data, commands etag and size are available to provide this data from the larger info set.


Remote objects can be deleted using the commands rm or remove. While the majority of radula commands follow the position pattern of subject, target, the deletion command operates exclusively on remote objects. Therefore, it is one of the few that accept an arbitrary number of arguments. Globs are supported if they are quoted so as not to expand in the shell.

Use the -n,`–dry-run` flag to preview deletions without making any changes.

[bibby@machine ~]$ radula --dry-run rm mybucket/x
DRY-RUN: rm mybucket/x

[bibby@machine ~]$ radula rm mybucket/x 'mybucket/y*'

Cleaning up messes

If multipart uploads go awry, they can leave behind some unfinished artifacts in the form of orphaned upload parts. radula can now list these can clean up.

The commands multipart-list, mp-list, and mpl are equivalent. For these examples, I’ve chosen to use mp-list.

Listing can be done by bucket or for a key:

# list multipart uploads for a bucket
$ radula mp-list mybucket
bibby    ones.img        2~Q8r-pWTmMTbx_rhHa8-u3I3m-vjCF5F       Andrew Bibby    2015-09-23T19:39:14.000Z
bibby    zeros.img       2~MvM7KTr2sMcS_SfVzWO7T0chzJRUqvm       Andrew Bibby    2015-09-23T19:35:44.000Z

# list multipart uploads for a key
$ radula mp-list mybucket/zeros.img
bibby    zeros.img       2~MvM7KTr2sMcS_SfVzWO7T0chzJRUqvm       Andrew Bibby    2015-09-23T19:35:44.000Z

Cleaning up a failed multi-part upload is as easy using a clean command in place of list.

The commands multipart-clean, mp-clean, and mpc are equivalent. For these examples, I’ve chosen to use mp-clean.

# clean multipart uploads for a key
$ radula mp-clean mybucket/zeros.img
INFO:root:Canceling zeros.img 2~MvM7KTr2sMcS_SfVzWO7T0chzJRUqvm

# clean multipart uploads for a bucket
$ radula mp-list mybucket
INFO:root:Canceling ones.img 2~Q8r-pWTmMTbx_rhHa8-u3I3m-vjCF5F

Streaming Copy

Since radula 0.5.0, users are able to copy between different ceph installations, or different buckets within the same installation, without copying to the local disk. To facilitate this in the friendliest possible manner, we’ve extended the boto configuration slightly to be able to specify a separate s3 host for a particular profile.

The profile sections of ~/.boto or /etc/boto.cfg can now accept the following items that are not supported by regular boto:

  • host (string)

  • port (int)

  • is_secure (bool)

An example extended profile

[profile second_ceph]
aws_access_key_id = wxyz...
aws_secret_access_key = 9765432...
host = second.ceph.of.mine
port = 8184

The commans streaming-copy and sc are equivalent. For these example, I’ve chosen to use sc.

When copying, the -p flag will apply the aws_profile for the source/subject. Omitting this flag will use the default boto credentials for the source.

The -d flag will specify the profile used for the destination/target to receive the files. Naming -d Default will use the default boto credentials for the destination.

Copy a file from first-ceph to second-ceph

radula -d second sc mybucket/file other_bucket/file

The above command used the default boto profile to send file from mybucket located on the default ceph to the ceph defined in the profile named second.

Copy a file from second-ceph to first-ceph

radula -p second -d Default sc other_bucket/file mybucket/file

This is the inverse of the previous example. Using the second profile as the source/subject (as specified by -p second), we’re transfering a file to mybucket/file located on the default s3 using the default profile (as specified by -d Default).

Copy profile to profile

Avoiding the use of default profiles all together, you can copy using both -p and -d flags.

radula -p here -d there sc here/stuff there/stuff

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