Changes to um-setup to allow GCOM to install with Cylc 8

[theabro]

Following from GCOM:#242, GCOM will only be able to be installed with Cylc 8. As the um-setup script installs from the head of the GCOM trunk by default, this will cause problems when running this script after GCOM:#242 is commited unless Cylc 8 can be used.

The changes in um-setup have been made to:

1. Maintain the directory structure of the GCOM install as done under Cylc 7, to minimise changes needed elsewhere in the script.
2. Keep Cylc 7 as an option when needing to install older versions of GCOM (the -c 7 option)
3. Provide Cylc 8 as the default behaviour (although running with -c 8 will also make use of Cylc 8)

After Cylc 8 is used to install GCOM, the Cylc version is set back to 7 for use with ShumLib.

It may be best to not commit this pull request until GCOM:#242 has been commited, but to do so as soon as possible thereafter.

UM ticket um:#7839 will update UMDP X10 documentation on how to install and run the UM on the VM.

When Cylc 8 is used, additional information is given when the um-setup script is run:

INSTALLED gcom_install from /tmp/tmp.nxxEAXDBBI/wc/rose-stem
INFO - Workflow: gcom_install
INFO - Scheduler: url=tcp://vagrant:43001 pid=169780
INFO - Workflow publisher: url=tcp://vagrant:43092
INFO - Run: (re)start number=1, log rollover=1
INFO - Cylc version: 8.3.6
INFO - Run mode: live
INFO - Initial point: 1
INFO - Final point: 1
INFO - Workflow shutting down - AUTOMATIC

This has been tested with Andy Malcolm's vn8.3_cylc8 branch with UM13.7. This has been tested with rose-stem and all jobs completed successfully.

The command

um-setup -s fcm:shumlib.x_tr@um13.7 -g fcm:gcom.x_br/dev/andymalcolm/vn8.3_cylc8

was used to install GCOM. To install the current GCOM head of trunk, the following command was tested, and GCOM installed successfully

um-setup -s fcm:shumlib.x_tr@um13.7 -c 7

[r-sharp]

Just checking, as I was looking as part of SR for UM:7839...
Does this logic work if "-c" is not the last argument provided ? becasue if it's not the last argument, after 'shift' surely $1 will be the next argument - so users will get the message "Cylc version for GCOM must be 7 or 8", but it won't be clear what was read and 'used' as the cylc version.
I mean, it's not significantly worse than the rest of the argument parsing stuff here (they all seem to check to see if there's a $1, but none of them have a default if there isn't, they just die on the spot.
Also, as the script drops out of the case statement (assuming it survived ingesting the next arg as a value for cylc_version).
Assuming the other values are sanity checked further down, by all means keep the sanity check on the value being 7 or 8, but add "got $cylc_version" to the error message so at least the user gets a clue as to what it's ingested.
I think however it would be safer to also remove the "else cylc_version='8'" and just give the same error as everything else if no supplementary arg was provided. Otherwise "um-setup -c -s <some/path/somewhere>" is just going to cause headaches all round when it returns with "unrecognised argument: <some/path/somewhere>"

[theabro]

Many thanks. I have updated in 23ad19b.

I have tested this and the -c can come first and behaves correctly unless there is no argument given, when the error is then, e.g.

vagrant@vagrant:~$ um-setup -c -s fcm:shumlib.x_tr@um13.7 -g fcm:gcom.x_br/dev/andymalcolm/vn8.3_cylc8
./um-setup: line 43: [: -s: integer expression expected
Unrecognised argument: fcm:shumlib.x_tr@um13.7
Usage: um-setup [-g gcom_path] [-s shumlib_path] [-c GCOM Cylc version]

Options:
  -c [7/8]   Cylc version to use (7 or 8) for GCOM install (default=8)
  -g path    GCOM source location (working copy or repository location)
  -h         Show this help and exit
  -s path    Shumlib source location (working copy or repository location)

The error message has been updated so that the Cylc version is returned if it isn't 7 or 8, e.g.

vagrant@vagrant:~$ um-setup -c 9 -s fcm:shumlib.x_tr@um13.7 -g fcm:gcom.x_br/dev/andymalcolm/vn8.3_cylc8
Cylc version for GCOM must be 7 or 8, provided 9
Usage: um-setup [-g gcom_path] [-s shumlib_path] [-c GCOM Cylc version]

Options:
  -c [7/8]   Cylc version to use (7 or 8) for GCOM install (default=8)
  -g path    GCOM source location (working copy or repository location)
  -h         Show this help and exit
  -s path    Shumlib source location (working copy or repository location)

If the -c is at the end of the line then the error message is slightly nicer, as it would be for the other arguments

vagrant@vagrant:~$ um-setup -s fcm:shumlib.x_tr@um13.7 -c
Cylc version not provided
Usage: um-setup [-g gcom_path] [-s shumlib_path] [-c GCOM Cylc version]

Options:
  -c [7/8]   Cylc version to use (7 or 8) for GCOM install (default=8)
  -g path    GCOM source location (working copy or repository location)
  -h         Show this help and exit
  -s path    Shumlib source location (working copy or repository location)

[theabro]

GCOM:#242 has now been committed, so can this pull request be committed to enable VM system to keep in line with the head of GCOM trunk?