prescript

About

prescript is an automation tool to run other interactive clis and respond to their output. Using a script file, it will watch the output of a cli application, responding with its own input.

Current Status: Early alpha

Installation

go get github.com/rjnienaber/prescript/cmd/prescript

Example

{
  "version": "0.1",
  "runs": [{
    "executable": "vintbas",
    "arguments": ["examples/dice/dice.bas"],
    "exitCode": 0,
    "steps": [{
      "line": "HOW MANY ROLLS? ",
      "input": "5000"
    }, {
      "line": "TRY AGAIN? ",
      "input": "N"
    }]
  }]
}

We'll execute a BASIC computer program called dice.bas by running it against the Vintage BASIC interpreter. When executed by itself, it prompts the user twice: Once for the number of rolls and then again to find out if the user wants to roll again. Both steps are automated in the above script and the program exits successfully:

$ time ./prescript play examples/dice/dice.json 
                                  DICE
               CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY



THIS PROGRAM SIMULATES THE ROLLING OF A
PAIR OF DICE.
YOU ENTER THE NUMBER OF TIMES YOU WANT THE COMPUTER TO
'ROLL' THE DICE.  WATCH OUT, VERY LARGE NUMBERS TAKE
A LONG TIME.  IN PARTICULAR, NUMBERS OVER 5000.

HOW MANY ROLLS? 5000

TOTAL SPOTS   NUMBER OF TIMES
 2             147 
 3             302 
 4             426 
 5             565 
 6             668 
 7             811 
 8             683 
 9             558 
 10            444 
 11            243 
 12            153 


TRY AGAIN? N

real	0m0.026s
user	0m0.028s
sys	0m0.000s

The script acts effectively like a state machine, with each step the next state that is being waited on. Since prescript doesn't use a timing mechanism to know when to input data, the automation script should finish as quickly as the cli can execute its work.

Commands & Options

play

Runs prescripted responses against an interactive cli

prescript play [script file] [optional executable] [flags]

Option	Description	Type	Default	Required?
[script file]	the script to use that contains the automated steps	bool		Yes
[executable]	an executable to run the script against	bool		No
-d	dont fail on external command failures	bool	false	No
-l	log level to use with logs (e.g. none, debug, info)	enum	none	No
-q	no output	bool	false	No
-t	timeout waiting for output from external command	bool	30s	No

record

Runs an interactive cli, records responses and generates a script for use with play

prescript record [script file] [executable] [flags] -- [args]

Option	Description	Type	Default	Required?
[script file]	the script to use that contains the automated steps	bool		Yes
[executable]	an executable to run the script against	bool		Yes

N.B. The -- convention is used to stop processing arguments for prescript. Any arguments after this point are passed to the executable.

Get in touch

• Slack: Find me as @rjnienaber on https://gophers.slack.com/
• Twitter: @rjnienaber