usage: caom2-repo visit [-h]
                        [--cert CERT | -n | --netrc-file NETRC_FILE | -u USER]
                        [--host HOST] [--resource-id RESOURCE_ID]
                        [-d | -q | -v] --plugin PLUGIN [--start START]
                        [--end END] [--halt-on-error]
                        collection

Visit observations in a collection

positional arguments:
  collection            data collection in CAOM2 repo

optional arguments:
  --cert CERT           location of your X509 certificate to use for
                        authentication (unencrypted, in PEM format)
  -d, --debug           debug messages
  --end END             latest observation to visit (UTC IVOA format: YYYY-mm-
                        ddTH:M:S)
  --halt-on-error       stop visitor on first update exception raised by
                        plugin
  -h, --help            show this help message and exit
  --host HOST           base hostname for services - used mainly for testing
                        (default: www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca)
  -n                    use .netrc in $HOME for authentication
  --netrc-file NETRC_FILE
                        netrc file to use for authentication
  --plugin PLUGIN       plugin class to update each observation
  -q, --quiet           run quietly
  --resource-id RESOURCE_ID
                        resource identifier (default
                        ivo://cadc.nrc.ca/caom2repo)
  --start START         earliest observation to visit (UTC IVOA format: YYYY-
                        mm-ddTH:M:S)
  -u, --user USER       name of user to authenticate. Note: application
                        prompts for the corresponding password!
  -v, --verbose         verbose messages

        Minimum plugin file format:
        ----
           from caom2 import Observation

           class ObservationUpdater:

            def update(self, observation):
                assert isinstance(observation, Observation), (
                    'observation {} is not an Observation'.format(observation))
                # custom code to update the observation
        ----
        
