Virtualization Plugins

  "diskFormat": {
    "enum": ["LATIN-1", "UTF-8"]
  }​

@plugin.linked.post_snapshot()
def linked_post_snapshot(staged_source, repository, source_config, snapshot_parameters):

  # Create a new snapshot data object
  snapshot = SnapshotDefinition()

  # Learn the current format of the data
  learn_format_command = "mydbms --get-disk-format"
  result = libs.run_bash(staged_source.connection, learn_format_command)
  format = result.stdout

  # Save the current format to the new data object
  snapshot.disk_format = format

  # <do any other work you need for your snapshot data here>

  return snapshot
​

@plugin.virtual.configure()
def configure(virtual_source, repository, snapshot):
  # Learn the on-disk format of the data we are provisioning from
  format = snapshot.disk_format

  # Tell our DBMS about the new dataset
  command = "mydbms add_dataset --path {} --format {}".format(virtual_source.parameters.mount_path, format)
  libs.run_bash(virtual_source.connection, command)

  # <do any other work required here>
​

So, now suppose this series of events happens:
1) User syncs a new dsource from a LATIN-1 dataset (this creates snapshot A on the dsource)
2) User provisions VDB1 from that new dsource (this creates snapshot B on the VDB)
3) User changes the disk format of VDB1 to be UTF-8
4) User provisions VDB2 from VDB1 using snapshot B

Even though VDB1 is currently using the UTF-8 format, it had been using LATIN-1 when the snapshot was taken.  So, the new VDB2's data will be starting out in LATIN-1 format.  The above strategy would let step 4 proceed correctly, because the snapshot data will tell your plugin code about the correct format.​

  "diskFormat": {    "enum": ["LATIN-1", "UTF-8"]  }​

@plugin.linked.post_snapshot()def linked_post_snapshot(staged_source, repository, source_config, snapshot_parameters):  # Create a new snapshot data object  snapshot = SnapshotDefinition()  # Learn the current format of the data  learn_format_command = "mydbms --get-disk-format"  result = libs.run_bash(staged_source.connection, learn_format_command)  format = result.stdout  # Save the current format to the new data object  snapshot.disk_format = format  # <do any other work you need for your snapshot data here>  return snapshot​

@plugin.virtual.configure()def configure(virtual_source, repository, snapshot):  # Learn the on-disk format of the data we are provisioning from  format = snapshot.disk_format  # Tell our DBMS about the new dataset  command = "mydbms add_dataset --path {} --format {}".format(virtual_source.parameters.mount_path, format)  libs.run_bash(virtual_source.connection, command)  # <do any other work required here>​

So, now suppose this series of events happens:
1) User syncs a new dsource from a LATIN-1 dataset (this creates snapshot A on the dsource)
2) User provisions VDB1 from that new dsource (this creates snapshot B on the VDB)
3) User changes the disk format of VDB1 to be UTF-8
4) User provisions VDB2 from VDB1 using snapshot B

Even though VDB1 is currently using the UTF-8 format, it had been using LATIN-1 when the snapshot was taken.  So, the new VDB2's data will be starting out in LATIN-1 format.  The above strategy would let step 4 proceed correctly, because the snapshot data will tell your plugin code about the correct format.​

• Who is in charge of deleting /tmp/folder1/file1?  Does it get deleted with VDB1? If so, does that cause problems for VDB2?  Or do the various VDBs need to coordinate with one another so that the last-deleted VDB will handle this cleanup?
• What happens when VDB1 is controlled by a different remote user than VDB2?  How will permissions/ownership work so that both users can access this same directory?
• What happens when VDB1 is migrated to a different remote host?  If there is data specific to VDB1 in /tmp/folder1/file1, will this need to be moved to the new host?  If there is shared VDB1/VDB2 data, will that need to be copied? How/when will your plugin code do that?
• Maybe you could outline what the problem is you're trying to solve?  Perhaps we could help explore other options that might work?

  "diskFormat": {    "enum": ["LATIN-1", "UTF-8"]  }​

@plugin.linked.post_snapshot()def linked_post_snapshot(staged_source, repository, source_config, snapshot_parameters):  # Create a new snapshot data object  snapshot = SnapshotDefinition()  # Learn the current format of the data  learn_format_command = "mydbms --get-disk-format"  result = libs.run_bash(staged_source.connection, learn_format_command)  format = result.stdout  # Save the current format to the new data object  snapshot.disk_format = format  # <do any other work you need for your snapshot data here>  return snapshot​

@plugin.virtual.configure()def configure(virtual_source, repository, snapshot):  # Learn the on-disk format of the data we are provisioning from  format = snapshot.disk_format  # Tell our DBMS about the new dataset  command = "mydbms add_dataset --path {} --format {}".format(virtual_source.parameters.mount_path, format)  libs.run_bash(virtual_source.connection, command)  # <do any other work required here>​

So, now suppose this series of events happens:
1) User syncs a new dsource from a LATIN-1 dataset (this creates snapshot A on the dsource)
2) User provisions VDB1 from that new dsource (this creates snapshot B on the VDB)
3) User changes the disk format of VDB1 to be UTF-8
4) User provisions VDB2 from VDB1 using snapshot B

Even though VDB1 is currently using the UTF-8 format, it had been using LATIN-1 when the snapshot was taken.  So, the new VDB2's data will be starting out in LATIN-1 format.  The above strategy would let step 4 proceed correctly, because the snapshot data will tell your plugin code about the correct format.​