This example illustrates how to running makeflow with the help of umbrella.

The user can specify the umbrella binary through the `--umbrella-binary`
option; and specify the umbrella spec through the `--umbrella-spec` option,
which will be the default umbrella specifcation for each rule. You can also
specify an Umbrella specification for a group of rule(s) in the Makefile by
putting the following directives before the rule(s) you want to apply the Umbrella
spec to:
.MAKEFLOW CATEGORY 1
.UMBRELLA SPEC convert_S.umbrella

In this case, the specified Umbrella spec will be applied to all the following
rules until a new ".MAKEFLOW CATEGORY..." directive is declared. All the rules
before the first ".MAKEFLOW CATEGORY ..." directive will use the Umbrella spec
specified by the `--umbrella-spec` option. If the `--umbrella-spec` option is
not specified, these rules will run without being wrapped by Umbrella.

To test makeflow with umbrella using local execution engine:
$ makeflow --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow

To test makeflow with umbrella using wq execution engine:
$ makeflow -T wq --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow

To test makefile with umbrella (without a default umbrella spec):
$ makeflow example_in_makefile.makeflow

To test makefile with umbrella (with a default umbrella spec):
$ makeflow --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example_in_makefile.makeflow

Usage of the `--umbrella-log-prefix` option of makeflow:
$ makeflow --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella --umbrella-log-prefix myumbrella.log example.makeflow

The default value of the `--umbrella-log-prefix` option is "<makefile-name>.umbrella.log".
After the makeflow completes, the umbrella log file for each rule will be in the format of "<umbrella-log-prefix>.<ruleid>".


Usage of the `--umbrella-mode` option of makeflow:
$ makeflow --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella --umbrella-mode parrot example.makeflow

Currently, the `--umbrella-mode` option can be set to the following three modes: local, parrot, and docker.

The default value of the `--umbrella-mode` option is local, which first tries
to utilize the docker mode, and tries to utilize the parrot mode if the docker
mode is not available.
