lsst.daf.persistence.storage.Storage Class Reference

Public Member Functions
def	__init__ (self)
def	getRepositoryCfg (self, uri)

Static Public Member Functions
def	registerStorageClass (scheme, cls)
def	putRepositoryCfg (cfg, uri)
def	getMapperClass (uri)
def	makeFromURI (uri, create=True)
def	isPosix (uri)
def	relativePath (fromUri, toUri)
def	absolutePath (fromUri, toUri)
def	search (uri, path)
def	storageExists (uri)

Public Attributes
	repositoryCfgs

Static Public Attributes
dictionary	storages = {}

Detailed Description

Base class for storages

Definition at line 29 of file storage.py.

Constructor & Destructor Documentation

__init__()

def lsst.daf.persistence.storage.Storage.__init__

(

self

)

Definition at line 34 of file storage.py.

    def __init__(self):
        self.repositoryCfgs = {}
 

Member Function Documentation

absolutePath()

def lsst.daf.persistence.storage.Storage.absolutePath (   fromUri,   toUri  )

static

Get an absolute path for the path from fromUri to toUri

Parameters
----------
fromUri : the starting location
    Description
toUri : the location relative to fromUri
    Description

Returns
-------
string
    URI that is absolutepath fromUri + toUri, if one exists. If toUri is absolute or if fromUri is not
    related to toUri (e.g. are of different storage types) then toUri will be returned.

Definition at line 220 of file storage.py.

    def absolutePath(fromUri, toUri):
        """Get an absolute path for the path from fromUri to toUri
 
        Parameters
        ----------
        fromUri : the starting location
            Description
        toUri : the location relative to fromUri
            Description
 
        Returns
        -------
        string
            URI that is absolutepath fromUri + toUri, if one exists. If toUri is absolute or if fromUri is not
            related to toUri (e.g. are of different storage types) then toUri will be returned.
        """
        fromUriParseRes = urllib.parse.urlparse(fromUri)
        toUriParseRes = urllib.parse.urlparse(toUri)
        if fromUriParseRes.scheme != toUriParseRes.scheme:
            return toUri
        storage = Storage.storages.get(fromUriParseRes.scheme, None)
        if not storage:
            return toUri
        return storage.absolutePath(fromUri, toUri)
 

getMapperClass()

def lsst.daf.persistence.storage.Storage.getMapperClass (   uri )

static

Get a mapper class cfg value from location described by uri.

Note that in legacy repositories the mapper may be specified by a file called _mapper at the uri
location, and in newer repositories the mapper would be specified by a RepositoryCfg stored at the uri
location.

.. warning::

    Storage is 'wet paint' and very likely to change during factorization of Butler back end and
    storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
    strongly discouraged.

Definition at line 103 of file storage.py.

    def getMapperClass(uri):
        """Get a mapper class cfg value from location described by uri.
 
        Note that in legacy repositories the mapper may be specified by a file called _mapper at the uri
        location, and in newer repositories the mapper would be specified by a RepositoryCfg stored at the uri
        location.
 
        .. warning::
 
            Storage is 'wet paint' and very likely to change during factorization of Butler back end and
            storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
            strongly discouraged.
 
        """
        ret = None
        parseRes = urllib.parse.urlparse(uri)
        if parseRes.scheme in Storage.storages:
            ret = Storage.storages[parseRes.scheme].getMapperClass(uri)
        else:
            raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
        return ret
 

getRepositoryCfg()

def lsst.daf.persistence.storage.Storage.getRepositoryCfg	(		self,
			uri
	)

Get a RepositoryCfg from a location specified by uri.

If a cfg is found then it is cached by the uri, so that multiple lookups
are not performed on storages that might be remote.

RepositoryCfgs are not supposed to change once they are created so this
should not lead to stale data.

Definition at line 70 of file storage.py.

    def getRepositoryCfg(self, uri):
        """Get a RepositoryCfg from a location specified by uri.
 
        If a cfg is found then it is cached by the uri, so that multiple lookups
        are not performed on storages that might be remote.
 
        RepositoryCfgs are not supposed to change once they are created so this
        should not lead to stale data.
        """
        cfg = self.repositoryCfgs.get(uri, None)
        if cfg:
            return cfg
        parseRes = urllib.parse.urlparse(uri)
        if parseRes.scheme in Storage.storages:
            cfg = Storage.storages[parseRes.scheme].getRepositoryCfg(uri)
            if cfg:
                self.repositoryCfgs[uri] = cfg
        else:
            raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
        return cfg
 

isPosix()

def lsst.daf.persistence.storage.Storage.isPosix (   uri )

static

Test if a URI is for a local filesystem storage.

This is mostly for backward compatibility; Butler V1 repositories were only ever on the local
filesystem. They may exist but not have a RepositoryCfg class. This enables conditional checking for a
V1 Repository.

This function treats 'file' and '' (no scheme) as posix storages, see
the class docstring for more details.

Parameters
----------
uri : string
    URI to the root of a Repository.

Returns
-------
Bool
    True if the URI is associated with a posix storage, else false.

Definition at line 168 of file storage.py.

    def isPosix(uri):
        """Test if a URI is for a local filesystem storage.
 
        This is mostly for backward compatibility; Butler V1 repositories were only ever on the local
        filesystem. They may exist but not have a RepositoryCfg class. This enables conditional checking for a
        V1 Repository.
 
        This function treats 'file' and '' (no scheme) as posix storages, see
        the class docstring for more details.
 
        Parameters
        ----------
        uri : string
            URI to the root of a Repository.
 
        Returns
        -------
        Bool
            True if the URI is associated with a posix storage, else false.
        """
        parseRes = urllib.parse.urlparse(uri)
        if parseRes.scheme in ('file', ''):
            return True
        return False
 

makeFromURI()

def lsst.daf.persistence.storage.Storage.makeFromURI (   uri,   create = True  )

static

Instantiate a StorageInterface sublcass from a URI.

.. warning::

    Storage is 'wet paint' and very likely to change during factorization of Butler back end and
    storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
    strongly discouraged.

Parameters
----------
uri : string
    The uri to the root location of a repository.
create : bool, optional
    If True The StorageInterface subclass should create a new
    repository at the root location. If False then a new repository
    will not be created.

Returns
-------
A Storage subclass instance, or if create is False and a repository
does not exist at the root location then returns None.

Raises
------
RuntimeError
    When a StorageInterface subclass does not exist for the scheme
    indicated by the uri.

Definition at line 126 of file storage.py.

    def makeFromURI(uri, create=True):
        '''Instantiate a StorageInterface sublcass from a URI.
 
        .. warning::
 
            Storage is 'wet paint' and very likely to change during factorization of Butler back end and
            storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
            strongly discouraged.
 
        Parameters
        ----------
        uri : string
            The uri to the root location of a repository.
        create : bool, optional
            If True The StorageInterface subclass should create a new
            repository at the root location. If False then a new repository
            will not be created.
 
        Returns
        -------
        A Storage subclass instance, or if create is False and a repository
        does not exist at the root location then returns None.
 
        Raises
        ------
        RuntimeError
            When a StorageInterface subclass does not exist for the scheme
            indicated by the uri.
        '''
        ret = None
        parseRes = urllib.parse.urlparse(uri)
        if parseRes.scheme in Storage.storages:
            theClass = Storage.storages[parseRes.scheme]
            try:
                ret = theClass(uri=uri, create=create)
            except NoRepositroyAtRoot:
                pass
        else:
            raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
        return ret
 

putRepositoryCfg()

def lsst.daf.persistence.storage.Storage.putRepositoryCfg (   cfg,   uri  )

static

Write a RepositoryCfg object to a location described by uri

Definition at line 92 of file storage.py.

    def putRepositoryCfg(cfg, uri):
        """Write a RepositoryCfg object to a location described by uri"""
        ret = None
        parseRes = urllib.parse.urlparse(uri)
        if parseRes.scheme in Storage.storages:
            ret = Storage.storages[parseRes.scheme].putRepositoryCfg(cfg, uri)
        else:
            raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
        return ret
 

registerStorageClass()

def lsst.daf.persistence.storage.Storage.registerStorageClass (   scheme,   cls  )

static

Register derived classes for lookup by URI scheme.

A scheme is a name that describes the form a resource at the beginning of a URI
e.g. 'http' indicates HTML and related code, such as is found in http://www.lsst.org

The only currently supported schemes are:
* 'file' where the portion of the URI after the // indicates an absolute locaiton on disk.
  for example: file:/my_repository_folder/
* '' (no scheme) where the entire string is a relative path on the local system
  for example "my_repository_folder" will indicate a folder in the current working directory with the
  same name.

See documentation for the urlparse python library for more information.

.. warning::

    Storage is 'wet paint' and very likely to change during factorization of Butler back end and
    storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
    strongly discouraged.

Parameters
----------
scheme : str
    Name of the `scheme` the class is being registered for, which appears at the beginning of a URI.
cls : class object
    A class object that should be used for a given scheme.

Definition at line 38 of file storage.py.

    def registerStorageClass(scheme, cls):
        """Register derived classes for lookup by URI scheme.
 
        A scheme is a name that describes the form a resource at the beginning of a URI
        e.g. 'http' indicates HTML and related code, such as is found in http://www.lsst.org
 
        The only currently supported schemes are:
        * 'file' where the portion of the URI after the // indicates an absolute locaiton on disk.
          for example: file:/my_repository_folder/
        * '' (no scheme) where the entire string is a relative path on the local system
          for example "my_repository_folder" will indicate a folder in the current working directory with the
          same name.
 
        See documentation for the urlparse python library for more information.
 
        .. warning::
 
            Storage is 'wet paint' and very likely to change during factorization of Butler back end and
            storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
            strongly discouraged.
 
        Parameters
        ----------
        scheme : str
            Name of the `scheme` the class is being registered for, which appears at the beginning of a URI.
        cls : class object
            A class object that should be used for a given scheme.
        """
        if scheme in Storage.storages:
            raise RuntimeError("Scheme '%s' already registered:%s" % (scheme, Storage.storages[scheme]))
        Storage.storages[scheme] = cls
 

relativePath()

def lsst.daf.persistence.storage.Storage.relativePath (   fromUri,   toUri  )

static

Get a relative path from a location to a location, if a relative path for these 2 locations exists.

Parameters
----------
fromPath : string
    A URI that describes a location at which to start.
toPath : string
    A URI that describes a target location.

Returns
-------
string
    A relative path that describes the path from fromUri to toUri, provided one exists. If a relative
    path between the two URIs does not exist then the entire toUri path is returned.

Definition at line 194 of file storage.py.

    def relativePath(fromUri, toUri):
        """Get a relative path from a location to a location, if a relative path for these 2 locations exists.
 
        Parameters
        ----------
        fromPath : string
            A URI that describes a location at which to start.
        toPath : string
            A URI that describes a target location.
 
        Returns
        -------
        string
            A relative path that describes the path from fromUri to toUri, provided one exists. If a relative
            path between the two URIs does not exist then the entire toUri path is returned.
        """
        fromUriParseRes = urllib.parse.urlparse(fromUri)
        toUriParseRes = urllib.parse.urlparse(toUri)
        if fromUriParseRes.scheme != toUriParseRes.scheme:
            return toUri
        storage = Storage.storages.get(fromUriParseRes.scheme, None)
        if not storage:
            return toUri
        return storage.relativePath(fromUri, toUri)
 

search()

def lsst.daf.persistence.storage.Storage.search (   uri,   path  )

static

Look for the given path in a storage root at URI; return None if it can't be found.

If the path contains an HDU indicator (a number in brackets before the
dot, e.g. 'foo.fits[1]', this will be stripped when searching and so
will match filenames without the HDU indicator, e.g. 'foo.fits'. The
path returned WILL contain the indicator though, e.g. ['foo.fits[1]'].


Parameters
----------
root : string
    URI to the the root location to search
path : string
    A filename (and optionally prefix path) to search for within root.

Returns
-------
string or None
    The location that was found, or None if no location was found.

Definition at line 246 of file storage.py.

    def search(uri, path):
        """Look for the given path in a storage root at URI; return None if it can't be found.
 
        If the path contains an HDU indicator (a number in brackets before the
        dot, e.g. 'foo.fits[1]', this will be stripped when searching and so
        will match filenames without the HDU indicator, e.g. 'foo.fits'. The
        path returned WILL contain the indicator though, e.g. ['foo.fits[1]'].
 
 
        Parameters
        ----------
        root : string
            URI to the the root location to search
        path : string
            A filename (and optionally prefix path) to search for within root.
 
        Returns
        -------
        string or None
            The location that was found, or None if no location was found.
        """
        parseRes = urllib.parse.urlparse(uri)
        storage = Storage.storages.get(parseRes.scheme, None)
        if storage:
            return storage.search(uri, path)
        return None
 

storageExists()

def lsst.daf.persistence.storage.Storage.storageExists (   uri )

static

Ask if a storage at the location described by uri exists

Parameters
----------
root : string
    URI to the the root location of the storage

Returns
-------
bool
    True if the storage exists, false if not

Definition at line 274 of file storage.py.

    def storageExists(uri):
        """Ask if a storage at the location described by uri exists
 
        Parameters
        ----------
        root : string
            URI to the the root location of the storage
 
        Returns
        -------
        bool
            True if the storage exists, false if not
        """
        parseRes = urllib.parse.urlparse(uri)
        storage = Storage.storages.get(parseRes.scheme, None)
        if storage:
            return storage.storageExists(uri)
        return None

Member Data Documentation

repositoryCfgs

lsst.daf.persistence.storage.Storage.repositoryCfgs

Definition at line 35 of file storage.py.

storages

dictionary lsst.daf.persistence.storage.Storage.storages = {}

static

Definition at line 32 of file storage.py.

---

The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-0.7.0/Linux64/daf_persistence/22.0.1-4-g243d05b+871c1b8305/python/lsst/daf/persistence/storage.py