* chore: Update help messages and adding examples.
This commit introduces fixes for the top-level help message as described in #187.
It does not address:
* #216 - Use `kn function` in help message when run as a plugin to kn
* #215 - Group main help message to put important commands to the top
* #214 - Make examples in usage message parameterizable
Uses the Cobra "Long" configuration for each command to provide more
descriptive text.
Example:
```console
faas help create 1.3m Mon 21 Sep 2020 09:55:40 PM EDT
Create a new Function, including initialization of local files and deployment
Creates a new Function project at 'path'. If 'path' does not exist, it is
created. The function name is the name of the leaf directory at path. After
creating the project, a container image is created and is deployed. This
command wraps 'init', 'build' and 'deploy' all up into one command.
The runtime, trigger, image name, image repository, and namespace may all be
specified as flags on the command line, and will subsequently be the default
values when an image is built or a Function is deployed. If the image name and
image repository are both unspecified, the user will be prompted for a
repository name, and the image name can be inferred from that plus the function
name. The function name, namespace, image name and repository name are all
persisted in the project configuration file .faas.yaml.
Usage:
faas create <path> [options] [flags]
Flags:
-c, --confirm Prompt to confirm all configuration options - $FAAS_CONFIRM
-h, --help help for create
-i, --image string Optional full image name, in form [registry]/[namespace]/[name]:[tag] for example quay.io/myrepo/project.name:latest (overrides --repository) - $FAAS_IMAGE
-n, --namespace string Override namespace into which the Function is deployed (on supported platforms). Default is to use currently active underlying platform setting - $FAAS_NAMESPACE
-r, --repository string Repository for built images, ex 'docker.io/myuser' or just 'myuser'. Optional if --image provided. - $FAAS_REPOSITORY
-l, --runtime string Function runtime language/framework. - $FAAS_RUNTIME (default "go")
--templates string Extensible templates path. - $FAAS_TEMPLATES (default "/home/lanceball/.config/faas/templates")
-t, --trigger string Function trigger (ex: 'http','events') - $FAAS_TRIGGER (default "http")
Global Flags:
--config string config file path (default "~/.faas/config")
-v, --verbose print verbose logs
```
The cobra package, magically appends "[flags]" to the usage string
if a command has flags. By adding "[options]" to the usage string,
we end up with help text that looks like this.
```
faas init <name> [options] [flags]
```
This commit fixes that.
- Replaces globally-scoped formatter function with methods
- Defines enumerated Format types
- Renames the 'output' flag 'format' due to confusion with command file descriptors
- FunctionDescription now Function
- Global verbose flag replaced with config struct based value throughout