Read command to run with Bolt from a file

[nicklewis]

Use Case

On certain systems, particularly network devices, files can't be written and therefore bolt script run doesn't work. In that case, it's useful to be able to run a long, multi-line script as a command.

Describe the Solution You Would Like

bolt command run @file.txt should read the command run a file named file.txt. If the file doesn't exist or can't be read, it should error.

[jpogran]

Testing this approach in PowerShell proves we can't use @ without escaping it because that's the spaltting operator :

➜ function bolt { param($command) "I'm reading content of $Command"; gc $command }
➜ bolt @foo.txt
ParserError:
Line |
   1 |  bolt @foo.txt
     |        ~~~~
     | The splatting operator '@' cannot be used to reference variables in an expression. '@foo' can be used
     | only as an argument to a command. To reference variables in an expression use '$foo'.

You can use the backtick escape character to get PowerShell to skip using @ and have it successfully pass down:

➜ bolt `@foo.txt
I'm reading content of @foo.txt
Get-Content: Cannot find path 'C:\Users\james\src\puppetlabs\bolt\@foo.txt' because it does not exist.
➜

That suffices the raw bolt command, if leaves a little to be desired in UX.

Using PowerShell Language features, we could have the cmdlet handle it without using @. A super naïve approach follows:

➜ function bolt {
>>   param(
>>     $command
>>   )
>>   if(Test-Path $command){
>>     "I'm reading content of $Command";
>>     $text = gc $command
>>     # invoke bolt
>>   }else{
>>     # invoke bolt
>>   }
>> }