This page describes some sample use cases for the Galaxy API and provides examples for these API calls. In addition to this page, there are functional examples of complete scripts in the docs/examples directory of the BioBlend source code repository.
To connect to a running Galaxy server, you will need an account on that Galaxy instance and an API key for the account. Instructions on getting an API key can be found at http://wiki.galaxyproject.org/Learn/API .
To open a connection call:
from bioblend.galaxy import GalaxyInstance
gi = GalaxyInstance(url='http://example.galaxy.url', key='your-API-key')
We now have a GalaxyInstance object which allows us to interact with the Galaxy server under our account, and access our data. If the account is a Galaxy admin account we also will be able to use this connection to carry out admin actions.
Methods for accessing histories and datasets are grouped under GalaxyInstance.histories.* and GalaxyInstance.datasets.* respectively.
To get information on the Histories currently in your account, call:
>>> gi.histories.get_histories()
[{u'id': u'f3c2b0f3ecac9f02',
u'name': u'RNAseq_DGE_BASIC_Prep',
u'url': u'/api/histories/f3c2b0f3ecac9f02'},
{u'id': u'8a91dcf1866a80c2',
u'name': u'June demo',
u'url': u'/api/histories/8a91dcf1866a80c2'}]
This returns a list of dictionaries containing basic metadata, including the id and name of each History. In this case, we have two existing Histories in our account, ‘RNAseq_DGE_BASIC_Prep’ and ‘June demo’. To get more detailed information about a History we can pass its id to the show_history method:
>>> gi.histories.show_history('f3c2b0f3ecac9f02', contents=False)
{u'annotation': u'',
u'contents_url': u'/api/histories/f3c2b0f3ecac9f02/contents',
u'id': u'f3c2b0f3ecac9f02',
u'name': u'RNAseq_DGE_BASIC_Prep',
u'nice_size': u'93.5 MB',
u'state': u'ok',
u'state_details': {u'discarded': 0,
u'empty': 0,
u'error': 0,
u'failed_metadata': 0,
u'new': 0,
u'ok': 7,
u'paused': 0,
u'queued': 0,
u'running': 0,
u'setting_metadata': 0,
u'upload': 0 },
u'state_ids': {u'discarded': [],
u'empty': [],
u'error': [],
u'failed_metadata': [],
u'new': [],
u'ok': [u'd6842fb08a76e351',
u'10a4b652da44e82a',
u'81c601a2549966a0',
u'a154f05e3bcee26b',
u'1352fe19ddce0400',
u'06d549c52d753e53',
u'9ec54455d6279cc7'],
u'paused': [],
u'queued': [],
u'running': [],
u'setting_metadata': [],
u'upload': []
}
}
This gives us a dictionary containing the History’s metadata. With contents=False (the default), we only get a list of ids of the datasets contained within the History; with contents=True we would get metadata on each dataset. We can also directly access more detailed information on a particular dataset by passing its id to the show_dataset method:
>>> gi.datasets.show_dataset('10a4b652da44e82a')
{u'data_type': u'fastqsanger',
u'deleted': False,
u'file_size': 16527060,
u'genome_build': u'dm3',
u'id': 17499,
u'metadata_data_lines': None,
u'metadata_dbkey': u'dm3',
u'metadata_sequences': None,
u'misc_blurb': u'15.8 MB',
u'misc_info': u'Noneuploaded fastqsanger file',
u'model_class': u'HistoryDatasetAssociation',
u'name': u'C1_R2_1.chr4.fq',
u'purged': False,
u'state': u'ok',
u'visible': True}
Methods for accessing Data Libraries are grouped under GalaxyInstance.libraries.*. Most Data Library methods are available to all users, but as only administrators can create new Data Libraries within Galaxy, the create_folder and create_library methods can only be called using an API key belonging to an admin account.
We can view the Data Libraries available to our account using:
>>> gi.libraries.get_libraries()
[{u'id': u'8e6f930d00d123ea',
u'name': u'RNA-seq workshop data',
u'url': u'/api/libraries/8e6f930d00d123ea'},
{u'id': u'f740ab636b360a70',
u'name': u'1000 genomes',
u'url': u'/api/libraries/f740ab636b360a70'}]
This gives a list of metadata dictionaries with basic information on each library. We can get more information on a particular Data Library by passing its id to the show_library method:
>>> gi.libraries.show_library('8e6f930d00d123ea')
{u'contents_url': u'/api/libraries/8e6f930d00d123ea/contents',
u'description': u'RNA-Seq workshop data',
u'name': u'RNA-Seq',
u'synopsis': u'Data for the RNA-Seq tutorial'}
We can get files into Data Libraries in several ways: by uploading from our local machine, by retrieving from a URL, by passing the new file content directly into the method, or by importing a file from the filesystem on the Galaxy server.
For instance, to upload a file from our machine we might call:
>>> gi.libraries.upload_file_from_local_path('8e6f930d00d123ea', '/local/path/to/mydata.fastq', file_type='fastqsanger')
Note that we have provided the id of the destination Data Library, and in this case we have specified the type that Galaxy should assign to the new dataset. The default value for file_type is ‘auto’, in which case Galaxy will attempt to guess the dataset type.
Methods for accessing workflows are grouped under GalaxyInstance.workflows.*.
To get information on the Workflows currently in your account, use:
>>> gi.workflows.get_workflows()
[{u'id': u'e8b85ad72aefca86',
u'name': u"TopHat + cufflinks part 1",
u'url': u'/api/workflows/e8b85ad72aefca86'},
{u'id': u'b0631c44aa74526d',
u'name': u'CuffDiff',
u'url': u'/api/workflows/b0631c44aa74526d'}]
This returns a list of metadata dictionaries. We can get the details of a particular Workflow, including its steps, by passing its id to the show_workflow method:
>>> gi.workflows.show_workflow('e8b85ad72aefca86')
{u'id': u'e8b85ad72aefca86',
u'inputs':
{u'252':
{u'label': u'Input RNA-seq fastq',
u'value': u''
}
},
u'name': u"TopHat + cufflinks part 1",
u'steps':
{u'250':
{u'id': 250,
u'input_steps':
{u'input1':
{u'source_step': 252,
u'step_output': u'output'
}
},
u'tool_id': u'tophat',
u'type': u'tool'
},
u'251':
{u'id': 251,
u'input_steps':
{u'input':
{u'source_step': 250,
u'step_output': u'accepted_hits'
}
},
u'tool_id': u'cufflinks',
u'type': u'tool'
},
u'252':
{u'id': 252,
u'input_steps': {},
u'tool_id': None,
u'type': u'data_input'
}
},
u'url': u'/api/workflows/e8b85ad72aefca86'
}
To run a Workflow, we need to tell Galaxy which datasets to use for which workflow inputs. We can use datasets from Histories or Data Libraries.
Examine the Workflow above. We can see that it takes only one input file. That is:
>>> wf = gi.workflows.show_workflow('e8b85ad72aefca86')
>>> wf['inputs']
{u'252':
{u'label':
u'Input RNA-seq fastq',
u'value': u''
}
}
There is one input, labelled ‘Input RNA-seq fastq’. This input is passed to the Tophat tool and should be a fastq file. We will use the dataset we examined above, under View Histories and Datasets, which had name ‘C1_R2_1.chr4.fq’ and id ‘10a4b652da44e82a’.
To specify the inputs, we build a data map and pass this to the run_workflow method. This data map is a nested dictionary object which maps inputs to datasets. We call:
>>> datamap = dict()
>>> datamap['252'] = { 'src':'hda', 'id':'10a4b652da44e82a' }
>>> gi.workflows.run_workflow('e8b85ad72aefca86', datamap, history_name='New output history')
{u'history': u'0a7b7992a7cabaec',
u'outputs': [u'33be8ad9917d9207',
u'fbee1c2dc793c114',
u'85866441984f9e28',
u'1c51aa78d3742386',
u'a68e8770e52d03b4',
u'c54baf809e3036ac',
u'ba0db8ce6cd1fe8f',
u'c019e4cf08b2ac94'
]}
In this case the only input id is ‘252’ and the corresponding dataset id is ‘10a4b652da44e82a’. We have specified the dataset source to be ‘hda’ (HistoryDatasetAssociation) since the dataset is stored in a History. See the Workflows API reference for allowed dataset specifications. We have also requested that a new History be created and used to store the results of the run, by setting history_name='New output history'.
The run_workflow call submits all the jobs which need to be run to the Galaxy workflow engine, with the appropriate dependencies so that they will run in order. The call returns immediately, so we can continue to submit new jobs while waiting for this workflow to execute. run_workflow returns the id of the output History and of the datasets that will be created as a result of this run. Note that these dataset ids are valid immediately, so we can specify these datasets as inputs to new jobs even before the files have been created, and the new jobs will be added to the queue with the appropriate dependencies.
If we view the output History after calling run_workflow, we will see something like:
>>> gi.histories.show_history('0a7b7992a7cabaec')
{u'annotation': u'',
u'contents_url': u'/api/histories/0a7b7992a7cabaec/contents',
u'id': u'0a7b7992a7cabaec',
u'name': u'New output history',
u'nice_size': u'0 bytes',
u'state': u'queued',
u'state_details': {u'discarded': 0,
u'empty': 0,
u'error': 0,
u'failed_metadata': 0,
u'new': 0,
u'ok': 0,
u'paused': 0,
u'queued': 8,
u'running': 0,
u'setting_metadata': 0,
u'upload': 0},
u'state_ids': {u'discarded': [],
u'empty': [],
u'error': [],
u'failed_metadata': [],
u'new': [],
u'ok': [],
u'paused': [],
u'queued': [u'33be8ad9917d9207',
u'fbee1c2dc793c114',
u'85866441984f9e28',
u'1c51aa78d3742386',
u'a68e8770e52d03b4',
u'c54baf809e3036ac',
u'ba0db8ce6cd1fe8f',
u'c019e4cf08b2ac94'],
u'running': [],
u'setting_metadata': [],
u'upload': []
}
}
In this case, because the submitted jobs have not had time to run, the output History contains 8 datasets in the ‘queued’ state and has a total size of 0 bytes. If we make this call again later we should instead see completed output files.
User management is only available to Galaxy administrators, that is, the API key used to connect to Galaxy must be that of an admin account.
To get a list of users, call:
>>> gi.users.get_users()
[{u'email': u'userA@unimelb.edu.au',
u'id': u'975a9ce09b49502a',
u'quota_percent': None,
u'url': u'/api/users/975a9ce09b49502a'},
{u'email': u'userB@student.unimelb.edu.au',
u'id': u'0193a95acf427d2c',
u'quota_percent': None,
u'url': u'/api/users/0193a95acf427d2c'}]