How to start Azure Storage Emulator from within a program

Question

I have some unit tests that use Azure Storage. When running these locally, I want them to use the Azure Storage emulator which is part of the Azure SDK v1.5. If the emulator isn't running, I want it to be started.

To start the emulator from the command line, I can use this:

"C:\Program Files\Windows Azure SDK\v1.5\bin\csrun" /devstore

This works fine.

When I try to start it using this C# code, it crashes:

using System.IO;
using System.Diagnostics;
...
ProcessStartInfo processToStart = new ProcessStartInfo() 
{   
    FileName = Path.Combine(SDKDirectory, "csrun"),
    Arguments = "/devstore"
};
Process.Start(processToStart);

I've tried fiddling with a number of ProcessStartInfo settings, but nothing seems to work. Is anybody else having this problem?

I've checked the Application Event Log and found the following two entries:

Event ID: 1023 .NET Runtime version 2.0.50727.5446 - Fatal Execution Engine Error (000007FEF46B40D2) (80131506)

Event ID: 1000 Faulting application name: DSService.exe, version: 6.0.6002.18312, time stamp: 0x4e5d8cf3 Faulting module name: mscorwks.dll, version: 2.0.50727.5446, time stamp: 0x4d8cdb54 Exception code: 0xc0000005 Fault offset: 0x00000000001de8d4 Faulting process id: 0x%9 Faulting application start time: 0x%10 Faulting application path: %11 Faulting module path: %12 Report Id: %13

Answer 1

Updated 1/19/2015:

After doing more testing (i.e., running several builds), I've discovered that WAStorageEmulator.exe's status API is actually broken in a couple of significant ways (which may or may not have impact on how you use it).

The status reports False even when an existing process is running if the user differs between the existing running process and the user used to launch the status process. This incorrect status report will lead to a failure to launch the process that looks like this:

C:\Program Files (x86)\Microsoft SDKs\Azure\Storage Emulator>WAStorageEmulator.exe status

Windows Azure Storage Emulator 3.4.0.0 command line tool
IsRunning: False
BlobEndpoint: http://127.0.0.1:10000/
QueueEndpoint: http://127.0.0.1:10001/
TableEndpoint: http://127.0.0.1:10002/

C:\Program Files (x86)\Microsoft SDKs\Azure\Storage Emulator>WAStorageEmulator.exe start

Windows Azure Storage Emulator 3.4.0.0 command line tool
Error: Port conflict with existing application.

Additionally, the status command appears only to report the endpoints specified in WAStorageEmulator.exe.config, not those of the existing running process. I.e., if you start the emulator, then make a change to the config file, and then call status, it will report the endpoints listed in the config.

Given all of these caveats, it may, in fact, simply be better to use the original implementation as it appears to be more reliable.

I will leave both so others can choose whichever solution works for them.

Updated 1/18/2015:

I have fully rewritten this code to properly leverage WAStorageEmulator.exe's status API per @RobertKoritnik's request.

public static class AzureStorageEmulatorManager
{
    public static bool IsProcessRunning()
    {
        bool status;

        using (Process process = Process.Start(StorageEmulatorProcessFactory.Create(ProcessCommand.Status)))
        {
            if (process == null)
            {
                throw new InvalidOperationException("Unable to start process.");
            }

            status = GetStatus(process);
            process.WaitForExit();
        }

        return status;
    }

    public static void StartStorageEmulator()
    {
        if (!IsProcessRunning())
        {
            ExecuteProcess(ProcessCommand.Start);
        }
    }

    public static void StopStorageEmulator()
    {
        if (IsProcessRunning())
        {
            ExecuteProcess(ProcessCommand.Stop);
        }
    }

    private static void ExecuteProcess(ProcessCommand command)
    {
        string error;

        using (Process process = Process.Start(StorageEmulatorProcessFactory.Create(command)))
        {
            if (process == null)
            {
                throw new InvalidOperationException("Unable to start process.");
            }

            error = GetError(process);
            process.WaitForExit();
        }

        if (!String.IsNullOrEmpty(error))
        {
            throw new InvalidOperationException(error);
        }
    }

    private static class StorageEmulatorProcessFactory
    {
        public static ProcessStartInfo Create(ProcessCommand command)
        {
            return new ProcessStartInfo
            {
                FileName = @"C:\Program Files (x86)\Microsoft SDKs\Azure\Storage Emulator\WAStorageEmulator.exe",
                Arguments = command.ToString().ToLower(),
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                UseShellExecute = false,
                CreateNoWindow = true
            };
        }
    }

    private enum ProcessCommand
    {
        Start,
        Stop,
        Status
    }

    private static bool GetStatus(Process process)
    {
        string output = process.StandardOutput.ReadToEnd();
        string isRunningLine = output.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries).SingleOrDefault(line => line.StartsWith("IsRunning"));

        if (isRunningLine == null)
        {
            return false;
        }

        return Boolean.Parse(isRunningLine.Split(':').Select(part => part.Trim()).Last());
    }

    private static string GetError(Process process)
    {
        string output = process.StandardError.ReadToEnd();
        return output.Split(':').Select(part => part.Trim()).Last();
    }
}

And the corresponding tests:

[TestFixture]
public class When_starting_process
{
    [Test]
    public void Should_return_started_status()
    {
        if (AzureStorageEmulatorManager.IsProcessRunning())
        {
            AzureStorageEmulatorManager.StopStorageEmulator();
            Assert.That(AzureStorageEmulatorManager.IsProcessRunning(), Is.False);
        }

        AzureStorageEmulatorManager.StartStorageEmulator();
        Assert.That(AzureStorageEmulatorManager.IsProcessRunning(), Is.True);
    }
}

[TestFixture]
public class When_stopping_process
{
    [Test]
    public void Should_return_stopped_status()
    {
        if (!AzureStorageEmulatorManager.IsProcessRunning())
        {
            AzureStorageEmulatorManager.StartStorageEmulator();
            Assert.That(AzureStorageEmulatorManager.IsProcessRunning(), Is.True);
        }

        AzureStorageEmulatorManager.StopStorageEmulator();
        Assert.That(AzureStorageEmulatorManager.IsProcessRunning(), Is.False);
    }
}

Original post:

I took Doug Clutter's and Smarx's code one step further and created a utility class:

The code below has been updated to work on both Windows 7 and 8 and now points at the new storage emulator path as of SDK 2.4.**

public static class AzureStorageEmulatorManager
{
    private const string _windowsAzureStorageEmulatorPath = @"C:\Program Files (x86)\Microsoft SDKs\Azure\Storage Emulator\WAStorageEmulator.exe";
    private const string _win7ProcessName = "WAStorageEmulator";
    private const string _win8ProcessName = "WASTOR~1";

    private static readonly ProcessStartInfo startStorageEmulator = new ProcessStartInfo
    {
        FileName = _windowsAzureStorageEmulatorPath,
        Arguments = "start",
    };

    private static readonly ProcessStartInfo stopStorageEmulator = new ProcessStartInfo
    {
        FileName = _windowsAzureStorageEmulatorPath,
        Arguments = "stop",
    };

    private static Process GetProcess()
    {
        return Process.GetProcessesByName(_win7ProcessName).FirstOrDefault() ?? Process.GetProcessesByName(_win8ProcessName).FirstOrDefault();
    }

    public static bool IsProcessStarted()
    {
        return GetProcess() != null;
    }

    public static void StartStorageEmulator()
    {
        if (!IsProcessStarted())
        {
            using (Process process = Process.Start(startStorageEmulator))
            {
                process.WaitForExit();
            }
        }
    }

    public static void StopStorageEmulator()
    {
        using (Process process = Process.Start(stopStorageEmulator))
        {
            process.WaitForExit();
        }
    }
}