This module implements the default behavior for the FTS3 system for TPC and source SE selection
- class DIRAC.DataManagementSystem.private.FTS3Plugins.DefaultFTS3Plugin.DefaultFTS3Plugin(vo=None)
” Default FTS3 plugin.
For the TPC selection, it returns the list configured in the CS. For the source SE selection, it calls
It is used to document what are the requirements for a real TPC plugin. It is a good idea for your plugin to inherit from this one if you only want to change one specific behavior.
Such plugins are meant to alter the TPC protocols list that an FTS3 job will use to transfer between two SEs, and possibly make a smart selection of the source SE.
They are called by
The class name must be “<PluginName>FTS3Plugin”
The plugin is instanciated once per
FTS3Operation, so it is a good place to do global initialization
vo (str) – Virtual Organization
- findMultiHopSEToCoverUpForWLCGFailure(srcSE, destSE)
This will return the SEName to be used as intermediate hop for a multiHop transfer.
To find the matching rule, we look in this order:
For the specific SE Name
For its base SE name
For a rule named “Default”
We do apply this order to the couple
(source, destination), starting with
priorityList) until we find a match.
The best way not to have a multihop is to not define a route, however there are cases when you may want to factorize your configuration, and thus want to disable a config. For example, you can define a multihop for a specific source to a base SE destination, but do not want multihop for a specific child of this base SE. Use the value
A lot more examples and illustrations are available in the test module
- inferFTSActivity(ftsOperation, rmsRequest, rmsOperation)
This will try to find which FTS activity should be applied to the FTS3Operation.
If nothing can be found, it will return None.
Note that this is only called if there is no hardcoded Activity in the RMS Operation Arguments.
- selectSourceSE(ftsFile, replicaDict, allowedSources)
For a given FTS3file object, select a source.
Note that the replicaDict may already have been filtered (for example, only active replicas are taken into account), so if you want to do exotic things, you may want to recheck the replicas
allowedSourcesis what comes from the RMS, so possibly from the TS. So up to you to ignore it or not
In this default implementation, we only consider the allowed sources and the active replicas, preferably on disk (already filtered in replicaDict) and return a random choice. This may be suboptimal as the selected source may involve multihop transfer, but hey….
ftsFiles – list of FTS3File object
replicaDict – list of replicas for the file
allowedSources – list of allowed sources
one SE name
ValueError – in case the plugin cannot select a sourceSE
- selectTPCProtocols(ftsJob=None, sourceSEName=None, destSEName=None, **kwargs)
This method has to return an ordered list of protocols that will be used by the source/dest StorageElements to agree on a common TPC protocol.
There are two ways to invoke the plugin. Either with an FTS3Job instance, or with specific parameters.
The FTS3Job object passed as parameter can be used to make a choice based on various parameters.
Specific parameters are passed when there is access to an FTS3Job already, like in the
Thus, it is possible that there is not enough information to make a decision without the FTS3Job. In that case, it is up to the plugin to decide whether to return the best possible answer or to raise a
In this default implementation, we just return the preference list that we have in the CS
FTS3Jobthat will submit the transfer
sourceSEName – Name of the source StorageElement
destSEName – Name of the destination StorageElement
an ordered TPC protocols list
ValueError – in case the plugin cannot select a protocol with the given info