datalad get
Synopsis
datalad get [-h] [-s LABEL] [-d PATH] [-r] [-R LEVELS] [-n] [-D DESCRIPTION]
[--reckless [auto|ephemeral|shared-...]] [-J NJOBS] [--version]
[PATH ...]
Description
Get any dataset content (files/directories/subdatasets).
This command only operates on dataset content. To obtain a new independent dataset from some source use the CLONE command.
By default this command operates recursively within a dataset, but not across potential subdatasets, i.e. if a directory is provided, all files in the directory are obtained. Recursion into subdatasets is supported too. If enabled, relevant subdatasets are detected and installed in order to fulfill a request.
Known data locations for each requested file are evaluated and data are obtained from some available location (according to git-annex configuration and possibly assigned remote priorities), unless a specific source is specified.
Getting subdatasets
Just as DataLad supports getting file content from more than one location, the same is supported for subdatasets, including a ranking of individual sources for prioritization.
The following location candidates are considered. For each candidate a cost is given in parenthesis, higher values indicate higher cost, and thus lower priority:
A datalad URL recorded in .gitmodules (cost 590). This allows for datalad URLs that require additional handling/resolution by datalad, like ria-schemes (ria+http, ria+ssh, etc.)
A URL or absolute path recorded for git in .gitmodules (cost 600).
URL of any configured superdataset remote that is known to have the desired submodule commit, with the submodule path appended to it. There can be more than one candidate (cost 650).
In case .gitmodules contains a relative path instead of a URL, the URL of any configured superdataset remote that is known to have the desired submodule commit, with this relative path appended to it. There can be more than one candidate (cost 650).
In case .gitmodules contains a relative path as a URL, the absolute path of the superdataset, appended with this relative path (cost 900).
Additional candidate URLs can be generated based on templates specified as configuration variables with the pattern
datalad.get.subdataset-source-candidate-<name>
where NAME is an arbitrary identifier. If name starts with three digits (e.g. ‘400myserver’) these will be interpreted as a cost, and the respective candidate will be sorted into the generated candidate list according to this cost. If no cost is given, a default of 700 is used.
A template string assigned to such a variable can utilize the Python format mini language and may reference a number of properties that are inferred from the parent dataset’s knowledge about the target subdataset. Properties include any submodule property specified in the respective .gitmodules record. For convenience, an existing datalad-id record is made available under the shortened name ID.
Additionally, the URL of any configured remote that contains the respective submodule commit is available as remoteurl-<name> property, where NAME is the configured remote name.
Hence, such a template could be http://example.org/datasets/{id} or http://example.org/datasets/{path}, where {id} and {path} would be replaced by the datalad-id or PATH entry in the .gitmodules record.
If this config is committed in .datalad/config, a clone of a dataset can look up any subdataset’s URL according to such scheme(s) irrespective of what URL is recorded in .gitmodules.
Lastly, all candidates are sorted according to their cost (lower values first), and duplicate URLs are stripped, while preserving the first item in the candidate list.
- NOTE
Power-user info: This command uses git annex get to fulfill file handles.
Examples
Get a single file:
% datalad get <path/to/file>
Get contents of a directory:
% datalad get <path/to/dir/>
Get all contents of the current dataset and its subdatasets:
% datalad get . -r
Get (clone) a registered subdataset, but don’t retrieve data:
% datalad get -n <path/to/subds>
Options
PATH
path/name of the requested dataset component. The component must already be known to a dataset. To add new components to a dataset use the ADD command. Constraints: value must be a string or value must be NONE
-h, --help, --help-np
show this help message. –help-np forcefully disables the use of a pager for displaying the help message
-s LABEL, --source LABEL
label of the data source to be used to fulfill requests. This can be the name of a dataset sibling or another known source. Constraints: value must be a string or value must be NONE
-d PATH, --dataset PATH
specify the dataset to perform the add operation on, in which case PATH arguments are interpreted as being relative to this dataset. If no dataset is given, an attempt is made to identify a dataset for each input path. Constraints: Value must be a Dataset or a valid identifier of a Dataset (e.g. a path) or value must be NONE
-r, --recursive
if set, recurse into potential subdatasets.
-R LEVELS, --recursion-limit LEVELS
limit recursion into subdataset to the given number of levels. Alternatively, ‘existing’ will limit recursion to subdatasets that already existed on the filesystem at the start of processing, and prevent new subdatasets from being obtained recursively. Constraints: value must be convertible to type ‘int’ or value must be one of (‘existing’,) or value must be NONE
-n, --no-data
whether to obtain data for all file handles. If disabled, GET operations are limited to dataset handles. This option prevents data for file handles from being obtained.
-D DESCRIPTION, --description DESCRIPTION
short description to use for a dataset location. Its primary purpose is to help humans to identify a dataset copy (e.g., “mike’s dataset on lab server”). Note that when a dataset is published, this information becomes available on the remote side. Constraints: value must be a string or value must be NONE
-J NJOBS, --jobs NJOBS
how many parallel jobs (where possible) to use. “auto” corresponds to the number defined by ‘datalad.runtime.max-annex-jobs’ configuration item NOTE: This option can only parallelize input retrieval (get) and output recording (save). DataLad does NOT parallelize your scripts for you. Constraints: value must be convertible to type ‘int’ or value must be NONE or value must be one of (‘auto’,) [Default: ‘auto’]
--version
show the module and its version which provides the command