Silence Usage When an Error Occurs

[danielhelfand]

This pull request partially addresses #183. It sets SilenceUsage: true in root.go so the help message for each command does not display when an error occurs.

Previously, when an error was displayed, the usage of the command would display. An example is below:

$ tkn pr ls -n 
Error: flag needs an argument: 'n' in -n
Usage:
  tkn pipelinerun list [flags]

Aliases:
  list, ls

Examples:

# List all PipelineRuns of Pipeline name 'foo'
tkn pipelinerun list foo -n bar

# List all pipelineruns in a namespaces 'foo'
tkn pr list -n foo",


Flags:
      --allow-missing-template-keys   If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. (default true)
  -h, --help                          help for list
  -o, --output string                 Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file.
      --template string               Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].

Global Flags:
  -k, --kubeconfig string   kubectl config file (default: $HOME/.kube/config)
  -n, --namespace string    namespace to use (default: from $KUBECONFIG)

With the change in this pr, the output would change to the following:

$ tkn pr ls -n 
Error: flag needs an argument: 'n' in -n

My opinion is that displaying all the --help information makes the error message difficult to find and is much more information than the user needs to solve the situation.

What is still needed is an elegant way to suggest to the user to run --help for the specific subcommand. I am open to any suggestions that can happen as part of this pr or can be discussed in #183. This is something that looks like it is being discussed in the Cobra project.

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Includes tests (if functionality changed/added)
• Includes docs (if user facing)
• Commit messages follow commit message best practices

Release Notes

Error messages no longer display the usage of the CLI command for which the error occurred. 

[tekton-robot]

Hi @danielhelfand. Thanks for your PR.

I'm waiting for a tektoncd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[chmouel]

/ok-to-test

[sthaha]

@danielhelfand looks good to me; did you see if there are any associated doc changes i.e. did you run make man docs ?

[danielhelfand]

@sthaha Just ran make man docs and not seeing any changes.

[sthaha]

/lgtm

[sthaha]

/lgtm

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: danielhelfand, sthaha

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