Summary links SideCarCLI

One of the feature is to let the original process execute just a limited amount of time. For this, I have defined an option

var maxSeconds = app.Option(“-mS|–maxSeconds”, “max seconds for the StartApp to run”, CommandOptionType.SingleOrNoValue);

and the code for waiting is

Process p = new Process()
{
StartInfo = pi
};

//code

var res=p.WaitForExit(this.MaxSeconds);

//code

if (res)
{
exitCode = p.ExitCode;
RunFinishInterceptors(exitCode);
}
else
{
Console.WriteLine($”timeout {MaxSeconds} elapsed”);
exitCode = int.MinValue;
}

where the default value for this.MaxSeconds is –1 – wait undefinetely

Summary links SideCarCLI

For the SideCarCLI I have the concept of Line Interceptors. That means for each line from the original program another program will be start .

The json looks like this

“LineInterceptors”: [
{
“Name”: “WindowsStandardWindowsOutputInterceptor”,
“Arguments”: “/c echo \”{site} {line}\””,
“FullPath”: “cmd.exe”,
“FolderToExecute”: null,
“InterceptOutput”: true
},
{
“Name”: “NextInterceptor”,
“Arguments”: “/c echo {line}”,
“FullPath”: “cmd.exe”,
“FolderToExecute”: null,
“InterceptOutput”: true
}
]

and you can activate by command line

-aLi WindowsStandardWindowsOutputInterceptor

Pretty simple , right ? For the code , means intercepting each line

p.OutputDataReceived += P_OutputDataReceived;
p.ErrorDataReceived += P_ErrorDataReceived;

and then run the process

foreach(var item in runningInterceptors.LineInterceptors)
{
try
{

var local = item;
var dataToBeParsed=new Dictionary<string, string>();

if(this.argsRegex.Count>0)
{
foreach (var reg in argsRegex)
{
dataToBeParsed.Add(“{“+reg.Key+”}”, reg.Value);
}
}
dataToBeParsed[“{line}”]= e.Data;
allProcesses.TryAdd(local.Name, local.RunLineInterceptor(local.Name,dataToBeParsed));

}
catch (Exception ex)
{
Console.WriteLine($”LineInterceptor:{item?.Name} error:!!!” + ex.Message);
}
}

Every time it is interesting how a simple specification means multiple lines of code….

Summary links SideCarCLI

There are those days a great deal of command line applications that performs a variety of things. The problem is that you cannot control them . The command line performs their duty well – but , from time to time, you need something else integrated with this.

The pattern for this is https://docs.microsoft.com/en-us/azure/architecture/patterns/sidecar – it is applied to microservices , but why not applied to command lines ?

So – let’s start this project  with specifications.

Let’s suppose that I want to run an command line application – let name it StartApp. But I want also:

1. Intercept every line of the StartApp that is outputting to the console and run something with that with the line ( send to HTTP endpoint, log somewhere, and so on).
2. Intercept the finish of the StartApp and run something with the output ( either all lines, either with the result of the application)
3. Timers:
   • Do not let the StartApp to run more than an maximum amount of time
   • Run something periodically  with arguments  from the StartApp arguments

The solution is to make another application ( let’s name SideCarCLI ) that runs the  StartApplication.

What it is complicated her is how we pass the arguments of the SideCarCLI versus the arguments of the StartApp .