Summary

When writing Python software, your code is usually one of:

1. Python Functions (part of a larger system) or Libraries
2. Python Scripts – to be executed at command line
3. Web Services – performers (servers) to be used by invokers (clients)

Unified Interactive Command Modules (ICM) is a framework that allows you to make your code be any or all of the above – with near zero extra effort.

ICM permits you to automatically map Python callables to command-line – similar to click. ICM also permits you to automatically map Python callables to Web Services operations – similar to Java’s DropWizard.

Since “Unified Commands” embed their full information about their arguments and outcomes within themselves, it is possible build to generic GUI’s for ICMs that can drived the formation of their command line.

Benefits Of This Commands Oriented Approach

Benefits Of Building On Top Of “Operations” and “Commands”

Augmenting Python at its most basic level with the concepts and abstractions of “Commands” and “Operations” has many benefits.

Scripting, Web Services And More Than Unit Testing

• Python code in the form of “Commands” becomes immediately invokable at command-line-interface. Python scripting is simplified and made consistent.
• Since “Commands” are derived from “Operations” and since they can be made “Remote Operations”, we can use Swagger (OpenApi) to build Web Services based on Commands.
• Since Commands are Python callables that are easily executable from outside of the code, they are easily testable.

Commands Are Abstract Expectations Complete

Abstract Expectations Of Commands

• Every Command “knows” with what options, parameters and arguments it may be called.
• Every Command “knows” the syntax of its results.

Command Expectations Are Emitable

• Every Command can emit its full parameter expectations.
• Every Command can emit its full results syntax information.

ICM-Players: User Interfaces That Fulfill Command Expectations

ICM-Players Are Generic Fancy UIs That Build Command-Lines Since each Command can fully tell us – “emit” – its full expectations, we can build different types of user interfaces that present these expectations to the user.

The user can then specify these inputs in stages to produce complex command-lines.

Precedence: Other Similar Approaches

There is ample precedence for each of the 3 aspects that the ICM model puts forward:

1. Automated Mapping Of Command-Line To Python Callables
2. Automated Building Of Web Services Based On Collection Of Callables
3. Generic UIs that Invoke The Command-Line Or The Web Service

Automated Mapping Of Command-Line To Python Callables

Argparse/Optparse/Getopt. Built into Python. Complex.
[Compago](https://github.com/jmohr/compago) Very nice, but
unmaintained. Also, does not run on Python 3.
[Docopt](http://docopt.org/)
[Clint](https://github.com/kennethreitz/clint)
[Click](http://click.pocoo.org/3/)
https://pypi.python.org/pypi/snakeshell/0.4.0

Automated Mapping Of Command-Line To Python Callables

The concept and terminology of “Command” and “interactive” come from elisp (emacs lisp). But they have been modified and enhanced. In elisp:

The (interactive) special form declares that a function is a command, and that it may therefore be called interactively (via M-x). The argument arg-descriptor declares how to compute the arguments to the command when the command is called interactively.

A command may be called from Lisp programs like any other function, but then the caller supplies the arguments and arg-descriptor has no effect.

Therefore, in elisp the concepts of “Command” and “interactive” are directly linked. We consider that a mistake.

With ICMs “Command” and “interactive” are independent concepts.

Automated Building Of Web Services Based On Collection Of Callables

Java's dropwizard

Generic UIs that Invoke The Command-Line Or The Web Service

Swagger-UI

Specialized ICMs – Libraries, Packages, APPs And Frameworks

ICM is a foundational building block.

Concept of ICM is language independent, a practical subset of the capabilities of Python-ICM has been implemented as BASH-ICM.

MARMEE and GOSSONoT are examples of ICM Based Packages and ICM higher level frameworks.

Related Documents

Remote Operations Interactive Command Modules (RO-ICM)
Best Current (2018) Practices For Web Services Development
http://www.by-star.net/PLPC/180056 — [2]

A Generalized Swagger (OpenAPI) Centered Web Services Invocations And Testing Framework
http://www.by-star.net/PLPC/180057 — [1]

Bash Interactive Command Modules (Bash-ICM)
http://www.by-star.net/PLPC/180058 — []

Obtaining The Software

You can obtain complete source-code for ICM from:

PyPi Pip Install

pip install unisos.icm
pip install unisos.icmExamples

Github Repos

https://github.com/unisos-pip/icm

https://github.com/unisos-pip/icmExamples

Part Of ByStar DE and BISOS

ICM is Part Of A Much Bigger Picture.

ICM Is Part Of: The Libre-Halaal ByStar Digital Ecosystem

And Part Of: BISOS: ByStar Internet Services OS

ICM is being used and developed in that context.

Document Outline:

• The Unified Commands Model, Concepts And Terminology
• The Model Of ICM-Players And ICM-Apps
• ICM Specializations
• Direct And Remote Operations – Direct ICMs, Remote ICM Invokers, Remote ICM Performers
• Direct ICMs Command-Line Structure And Model
• Overview Of The unisos.icm Package
• Current Status And Next Steps

Unified Commands

Command (Unified Command)

A “Command” is a user invokable execution entry point.

A Unified Command can be invoked from:

• The Command Line Interface – (Foreign, Local, Interactive)
• Through A Web Services (Remote Operations) Invoker – (Foreign, Remote)
• Python Code – (Native, Local)

Terminology Of Native vs Foreign, Local vs Remote, Interactive vs Non-Interactive

Native Vs Foreign

Invocation of Commands can be “Native” (an ordinary call) or “Foreign” (a framework call).

Local Vs Remote Invocation of Commands can be “Local” (same process and machine) or “Remote” (different process or different machine).

Interactive Vs Non-Interactive For the purposes of the invokation an abstract Human-User may exist (interactive) or an abstract Human-User does no exist (non-interactive).

Terminimogy Of Callables, Operations And Commands

Operations Are Special Forms Of Callables

Operations are Callables whose arguments and results are “foreignly” specified.

Commands Are Special Special Forms Of Operations

Commands are Operations which are expection complete

Commands Are Special Forms Of Operations

Commands As Operations

Each Command has:

• A cmndName (an opName)
• Operations Arguments In The Form Of:
  • Cmnd-Options
  • Cmnd-Parameters
  • Cmnd-Arguments
• Operation Results In The Form Of:
  • stdExit, stdOut, stdErr
  • opOutcome

Commands Are Patterned After Operations

Commands Are aware of Command-Line

Each Command expects to be invoked from the command-line and is aware of Command-Line to python-callable mappings.

Commands Have Embedded In Themselves Full Arguments And Results Information

class Cmnd

Each Cmnd, through its methods can output its:

• Cmnd-Name
• Cmnd-Description
• Expected Parameters (and description of each expected Parameter)
• Expected Arguments (and description of expected Arguments)
• Expected outcome

Commands Have Embedded In Themselves Full Arguments And Results Information

class Cmnd

Is aware of how it has been invoked (Command-Line, Web Services, Python) and can validate its expectations.

Commands Have Embedded In Themselves Full Arguments And Results Information

When Invoked As Interactive

Commands get their parameters from command-line.

Commands write to their stdout, stderr

When Invoked As Non-Interactive

Commands get their parameters to have been passed to them in full.

Comands may avoid writing to their stdout, stderr

Interactive Command Modules (ICMs) As Collections Of Related Commands

Collection Of Related Commands

When related Commands are grouped in a python module with a common __main__ entry, they for an “Interactive Commands Module (ICM)”.

Related And Common Parameters

Collection Of Related Commands

Parameters specification for different commands may be shared in an ICM.

An Overview Of ICM Framework, Modules And Players

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Figure 1: ICM Framework, Modules And Players

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Interactive Command Modules (ICMs) As Collections Of Related Commands

About ICM Players Based on the ICM’s self-contained info, ICM modules can be used at cmnd-line or through auto-generated User-Interfaces.

The Blee-ICM-Player (With Emacs and elisp)

Blee-ICM-Player

An emacs based ICM-Player has been implemented.

Abstraction Of ICM-Apps

ICM-Apps:

When a group of ICMs wish to have a UI which is more specialized than ICM-Players, custom UIs for their commands can be built.

That packaging of the custom UIs and the ICMs is called and ICM-App.

About BASH-ICMs

Concept of ICM is language independent.

In Python, Commands are implemented as a Class that encapsulates the expectations within the “Class Cmnd”.

In Bash, Commands are special forms of Bash functions.

A practical subset of the capabilities of Python-ICM has been implemented as Bash-ICM.

See BASH-ICMs for more details.

ICM Groupings

• ICM
• ICM.Packaged
• ICM.Packaged.basicPkg – Marme
• ICM.Packaged.toiimPkg
• ICM.Packaged.empnaPkg
• ICM.Grouped
• ICM.Grouped.Bisos
• ICM.Scattered(bxt)
• ICM.Scattered.mailingsProc
• ICM.Unitary – A Single ICM
• ICM.Standalone – A Single ICM With Library Included – Distributable

Frame Notes

About ICM Libraries – Collections Of Reusable ICMs

ICM “Commands” can be included in ICM-Libraries which can then be combined.

Development Workflow

Python Invocation Inputs: Complex Arguments Python Invocation Outputs: Complex Return Values

Command-Line Invocation Inputs: Options And Args Command-Line Invocation Outputs: stdout, stderr

Remote-Operation Invocation Inputs: parameters Remote-Operation Outputs: Results, Errors

You just write your python code, the CLI and Remote Operations are fully auto generated.

Benefits And Powers Of The ICM Unified Model

Most of your development life-cycle is in a local and single process environment.

At will you map to command line.

At will you can split the functionality to remote-operations (Web Services).

You can switch between the three models by maintaining a single code base.

ICM Performer Responders

ICM-Commands are directly invoked.

In a single process model where parameters and arguments and results are through the command line and file system.

An Overview Of Direct-Operations ICMs and ICM-Players

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Figure 2: Direct Operations Interactive Command Modules (DO-ICM)

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Frame Notes

Convertable To Web Services Performer

Auto Generation Of Web Services Performer

Since ICMs are expectation complete, their expectations can be converted to a swagger-file.

The swagger-code-generator will then use the swagger-file to generate web-services code.

Commands within the ICM then become “controllers” that the generated code uses.

All of this can be fully automated such that an ICM becomes a web-service performer without any coding.

Web Services ICM With Swagger Code Generators

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Figure 3: Web Services Interactive Command Module (WS-ICM) Using Swagger Code Generators

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Frame Notes

Common Direct ICMs Command Syntax And Model – Python And Bash Specific Features

Model And Terminology of Direct-ICM Command-Line is based on:

1. CmndsModule – icmCmndsModule
2. Cmnds – cmndName
3. Cmnd Options – optionName1 ... optionNameN
4. Cmnd Params – parmName1 ... paramNameN
5. Cmnd Args – arg1 ... argN

Which leads to the common ICMs command-line invocation syntax of

icmCmndsModule --optionNameN --parmNameN=paramValueN -i cmndName arg1 argN

Python and Bash ICMs, each have their own specific additional features.

Python DO-ICM Features

1. –examples – Frequently Invoked Menu Examples
2. –help – Usage – getopt Summary
3. Logging
4. Tracing and Debugging
5. –load – Run time additional code loading

Frequently Invoked Menu Example

Running the ICM with no options, params, cmnds or args or using the 
--examples option produces frequently invoked menu examples.

The examples menu is often tailored to desired usage patterns.
This is the best way of getting started.

Usage –help

Running the ICM with --help provides the usual getopt usage information.

Logging

With -v 30 -- default -- ICM results go to stdout.

With -v 20, ICMs also report Swagger specified inputs and output
with -v 15, ICMs also report http traffic as seen by requests
with -v 1, ICMs also report digestion of the swagger file

Tracing And Debugging

You can enable run time tracing of key callables 
(those decorated with @icm.subjectToTracking) by including:

 -v 1 --callTrackings monitor+ --callTrackings invoke+ 

Plugins – Loading Of Additional Python Code

Additional code can be added to an ICM at run time with the 

--load additionalCode.py

Python Method Invocations Of Commands

Commands can also be invoked from python. The cmnd() method of the icm.Cmnd() class needs to be called with interactive=False. Below is a demonstrational simple example.

icm.cmndList_mainsMethods().cmnd(
            interactive=False,
            importedCmnds=g_importedCmnds,
            mainFileName=__file__,
    )

See unisos.icmExamples pip package for more details.

ICM-Performers

Remote Operations Interactive Command Modules (RO-ICM)
Best Current (2018) Practices For Web Services Development
http://www.by-star.net/PLPC/180056 — [2]

ICM-Invokers

A Generalized Swagger (OpenAPI) Centered Web Services Invocations And Testing Framework
http://www.by-star.net/PLPC/180057 — [1]

Wrappers And Streams

pip install unisos.ucf

Wrappers And Streams

Add to warpers ICM-Instantiate

Common ICM Parameter – Out Stream Consumer/Usage Context –oUsage=icmPlayerBlee

Wrappers And Streams

pip install unisos.ucf

Wrappers And Streams

Python’s Abstract Syntax Tree (AST) is searched to locate all class Cmnd declarations, through which the mapping to the cmnd method is facilitated.

ICM-Invokers

In the context of ByStar and BISOS, both Python-ICMs and Bash-ICMs have been in use for more than a decade.

With the exception of full automation of web services conversion all features and capabilities mentioned in this document have been implemented.

Next Steps

ICM is now ready for general use.

If you use it, please send us your feedback.