l.c.v.branchfs : module documentation

Part of lp.codehosting.vfs

The Launchpad code hosting file system.

The way Launchpad presents branches is very different from the way it stores them. Externally, branches are reached using URLs that look like <schema>://launchpad.net/~owner/product/branch-name. Internally, they are stored by branch ID. Branch 1 is stored at 00/00/00/01 and branch 10 is stored at 00/00/00/0A. Further, these branches might not be stored on the same physical machine.

This means that our services need to translate the external paths into internal paths.

We also want to let users create new branches on Launchpad simply by pushing them up.

This means our services must detect events like 'make directory' and 'unlock branch' and translate them into Launchpad operations like 'create branch' and 'request mirror' before performing those operations.

So, we have a LaunchpadServer which implements the core operations -- translate a path, make a branch and request a mirror -- in terms of virtual paths.

This server does most of its work by querying an XML-RPC server that provides the IBranchFileSystem interface and passing what that returns to a ITransportDispatch object.

We hook the LaunchpadServer into Bazaar by implementing a AsyncVirtualTransport, a bzrlib.transport.Transport that wraps all of its operations so that they are translated by an object that implements translateVirtualPath. See transport.py for more information.

This virtual transport isn't quite enough, since it only does dumb path translation. We also need to be able to interpret filesystem events in terms of Launchpad branches. To do this, we provide a LaunchpadTransport that hooks into operations like mkdir and ask the LaunchpadServer to make a branch if appropriate.

Class NotABranchPath Raised when we cannot translate a virtual URL fragment to a branch.
Class UnknownTransportType Raised when we don't know the transport type.
Function get_path_segments Break up the given path into segments.
Function is_lock_directory Is 'absolute_path' a Bazaar branch lock directory?
Function get_real_branch_path Return the on-disk location of a branch.
Interface ITransportDispatch Turns descriptions of transports into transports.
Class BranchTransportDispatch Turns BRANCH_TRANSPORT tuples into transports that point to branches.
Class TransportDispatch Make transports for hosted branch areas and virtual control dirs.
Class LaunchpadInternalServer Server for Launchpad internal services.
Class DirectDatabaseLaunchpadServer No class docstring; 2/4 methods documented
Class _BaseLaunchpadServer Bazaar Server for translating Lanuchpad paths via XML-RPC.
def get_path_segments(path, maximum_segments=-1):
Break up the given path into segments.

If 'path' ends with a trailing slash, then the final empty segment is ignored.

def is_lock_directory(absolute_path):
Is 'absolute_path' a Bazaar branch lock directory?
def get_real_branch_path(branch_id):
Return the on-disk location of a branch.

This should be used only when local filesystem operations are required. For branch access, get_rw_server should be used. :param branch_id: The integer id of the branch in the database.

API Documentation for Launchpad, generated by pydoctor at 2020-01-21 00:00:12.