(design_proposal): chef cli catalog

docs/Chef-CLI-Catalog.md

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+# Chef CLI (Catalog)
+
+Throughout the history of Chef, we have created and acquired a variety
+of tools that have grown to a point that, as a Chef Operator, it is
+hard to know, discover and understand all of them. A few of the tools
+that our users use (almost) every day are:
+
+* chef (CLI that includes Policyfiles management)
+* hab (Habitat CLI)
+* inspec
+* ohai
+* kitchen (Test-kitchen)
+* knife
+* berks (Berkshelf)
+* cookstyle
+* delivery
+* chef-client
+* chef-run/chef-apply
+* chef-shell
+* chef-solo
+
+Currently, inside the latest version of Chef Workstation (and since version `0.10.41`),
+the team has implemented a top-level `chef` command that acts as a wrapper around chef
+commands. In this design proposal we expand this scope to be a proxy/catalog of all the
+user facing cli tools we package inside Chef Workstation.
+
+Quick diagram that illustrates the new Chef CLI Catalog:
+
+![chef-cli-catalog](img/chef-top-level-command.jpg)
+
+With this architecture, we would be able to integrate and modularize multiple tools
+in a single place and make the chef command a first-class citizen of our development
+experience. We will also be able to gather immediate information from our users of
+all our tools so we can understand what parts of our tooling are the most used and
+which areas can we improve.
+
+Once detecting such areas of improvement, we can have the flexibility to improve
+tools entirely or sub-sections of the tool. Say for instance, that our users run
+`knife search` around 30-50 times a day, if the command takes around 10-15
+seconds to run, we are consuming ~10 minutes a day from our users waiting for value.
+With this approach we could rewrite that specific sub-command to run 10x faster and
+give that time back to our users.
+
+![mocked-chef-help-command](img/mocked-chef-help-command.png)
+
+[Gist with a few mocked help commands.](https://gist.github.com/afiune/1dc854089002e182288a0452eaa91908)
+
+## Goals
+* Have a single, unified way to discover tools to interact with Chef products
+* A path to have consistent/usable performance on all supported platforms
+* Gather data about how our users consume and interact with our tools (Telemetry)
+* Agreement to a common UX standards of our (CLI) tools
+* Have the flexibility to rename tools and commands within our ecosystem
+* Enable developers to develop tools in any supported programming languages at Chef
+
+## Motivation
+
+    As a Chef Operator,
+    I need a unified Command Line Interface (CLI) that lets me interact with every Chef product,
+    so I can easly discover the capabilities of the Chef ecosystem.
+
+    As a Chef Developer,
+    I need to be able to gather information about how our users consume and interact with our tools,
+    so I can identify which commands are used the most and measure the usability and performance on all supported platforms.
+
+## Specification
+
+### Refactor the `chef-cli` (Policyfiles)
+With the purpose of having a better sub-command organization, we need to extract
+the Policyfile logic out from the `chef-cli` binary. The commands that need to
+be extracted are:
+
+```
+  install                 Install cookbooks from a Policyfile and generate a locked cookbook set
+  update                  Updates a Policyfile.lock.json with latest run_list and cookbooks
+  push                    Push a local policy lock to a policy group on the Chef Infra Server
+  show-policy             Show policyfile objects on the Chef Infra Server
+  diff                    Generate an itemized diff of two Policyfile lock documents
+  export                  Export a policy lock as a Chef Infra Zero code repo
+  clean-policy-revisions  Delete unused policy revisions on the Chef Infra Server
+  clean-policy-cookbooks  Delete unused policyfile cookbooks on the Chef Infra Server
+  delete-policy-group     Delete a policy group on the Chef Infra Server
+  delete-policy           Delete all revisions of a policy on the Chef Infra Server
+  undelete                Undo a delete command
+```
+
+The new binary name proposed is `chef-policy` that could initially be the same policyfiles
+ruby code that lives inside the `chef-cli`. The rest of the sub-commands will continue to
+live inside the `chef-cli` binary.
+
+The new `chef-policy` should contain the following sub-commands:
+```
+$ chef-policy install
+$ chef-policy update
+$ chef-policy push (includes push-archive)
+$ chef-policy show
+$ chef-policy diff
+$ chef-policy export
+$ chef-policy delete
+$ chef-policy undelete
+$ chef-policy clean revisions
+$ chef-policy clean cookbooks
+$ chef-policy group delete (and more? maybe show a policy group)
+```
+These sub-commands map to the previous top level policy commands. As an example, the
+previous command `chef clean-policy-revisions` would map to the new command
+`chef-policy clean revisions`.
+
+Once the new `chef-policy` exists, we need to update the `chef` catalog to point to
+the new binary and add a section called "Relocated Commands".
+
+The new help command of the `chef` catalog should look like:
+```
+$ chef
+Usage:
+    chef -h/--help
+    chef -v/--version
+    chef command [arguments...] [options...]
+
+Available Commands:
+    env                     Prints environment variables used by Chef Workstation
+    gem                     Runs the 'gem' command in context of the embedded Ruby
+    exec                    Runs the command in context of the embedded ruby
+    shell-init              Initialize your shell to use Chef Workstation as your primary Ruby
+    generate                Generate a new repository, cookbook, or other component
+    describe-cookbook       Prints cookbook checksum information used for cookbook identifier
+    policy                  Manage Chef Policyfiles
+
+Renamed Commands:
+    install                 Use: chef policy install
+    update                  Use: chef policy update
+    push                    Use: chef policy push
+    push-archive            Use: chef policy push
+    show-policy             Use: chef policy show
+    diff                    Use: chef policy diff
+    export                  Use: chef policy export
+    clean-policy-revisions  Use: chef policy clean revisions
+    clean-policy-cookbooks  Use: chef policy clean cookbooks
+    delete-policy-group     Use: chef policy group delete
+    delete-policy           Use: chef policy delete
+    undelete                Use: chef policy undelete
+
+Experimental Commands:
+    analyze                 Analyze artifacts from a Chef Infra Server
+```
+
+#### Open questions for further discussion with UX:
+* How do we want to present these sections? What is the right order?
+
+### Implement Telemetry into the `chef` catalog
+
+To start gathering information from the `chef` catalog we need to create a telemetry
+Go library. The design of this work will be captured in a separate document.
+
+### Route tools and binaries through the `chef` catalog
+
+The last thing we propose is routing all our tools and binaries through the `chef`
+catalog. An example would be the `hab` and `inspec` binaries that will be routed
+as `chef hab` and `chef inspec` accordingly.
+
+The complete output of the `chef` catalog should look like:
+```
+$ chef
+Usage:
+    chef -h/--help
+    chef -v/--version
+    chef command [arguments...] [options...]
+
+Available Commands:
+    env                     Prints environment variables used by Chef Workstation
+    gem                     Runs the 'gem' command in context of the embedded Ruby
+    exec                    Runs the command in context of the embedded ruby
+    shell-init              Initialize your shell to use Chef Workstation as your primary Ruby
+    generate                Generate a new repository, cookbook, or other component
+    describe-cookbook       Prints cookbook checksum information used for cookbook identifier
+    policy                  Manage Chef Policyfiles
+    hab                     Commands relating to Chef Habitat
+    inspec                  Tests and auditing your applications and infrastructure
+    kitchen                 Test cookbooks across any combination of platforms and test suites
+    knife                   An interface between a local chef-repo and the Chef Infra Server
+    ohai                    Collect system configuration data
+    client                  Agent that runs locally on every node that is under management by Chef Infra Server
+    run                     Execute ad-hoc tasks using Chef
+    apply                   Executable program that runs a single recipe
+    shell                   A recipe debugging tool that allows the use of breakpoints within recipes
+    berks                   Dependency manager for Chef cookbooks
+    cookstyle               Code linting tool that helps you write better Chef Infra cookbooks
+
+Relocated Commands:
+    install                 Use now: chef policy install
+    update                  Use now: chef policy update
+    push                    Use now: chef policy push
+    push-archive            Use now: chef policy push
+    show-policy             Use now: chef policy show
+    diff                    Use now: chef policy diff
+    export                  Use now: chef policy export
+    clean-policy-revisions  Use now: chef policy clean revisions
+    clean-policy-cookbooks  Use now: chef policy clean cookbooks
+    delete-policy-group     Use now: chef policy group delete
+    delete-policy           Use now: chef policy delete
+    undelete                Use now: chef policy undelete
+
+Experimental Commands:
+    analyze                 Analyze artifacts from a Chef Infra Server
+```
+
+### Automation of reference documentation
+
+Motivation:
+
+    As a technical writer
+    I want to add examples to the chef catalog documentation
+    so that users will know the tricky bits and the documentation gets updated automatically as the code evolves
+
+The documentation team is working towards meaningful automation of our reference
+documentation, this includes our CLI tools. This proposal includes working with
+the documentation team to implement an automation inside our `chef` catalog by
+adding and example field that can handle command line examples.
+
+### EXTRA: Present correct usage of sub-binaries
+
+An additional task from this proposal is the use of an environment variable that
+can control the "Usage" message of sub-binaries. Currently, the `chef-analyze`
+binary displays the usage message `chef-analyze [command]` when it is run directly
+and also when it is run from the `chef` catalog. We would like the usage message
+to be consistent with the way users execute the commands so if you run `chef analyze`
+the usage sould be `chef analyze [command]`; and if you run `chef-analyze` the
+usage should continue to be `chef-analyze [command]`.
+
+## Open points for further discussion:
+* Are we discouraging the use of individual sub-binaries like `knife` or `chef-run`?
+* What happens when a user runs a sub-binary without the prefix `chef`?
+    * How do we capture telemetry on usage when users directly access tools? (EG, `berks`, `inspec` instead of `chef berks`, `chef inspec`)
+* How are we communicating deprecations? (UX)
+* How are we communicating reorganization of sub-commands? (UX)
+
+## Downstream Impact
+* Re organization of Policyfiles commands inside the `chef-cli`
+* Effortless will need to point to the new `chef-policy`