[LinuxConsumption] Support mounting Azure file share with Run-From-Package

   Currently either Azure File share can be mounted or app can use Run-From-Package but not both simultaneously. This PR adds support for this scenario but only for PowerShell apps. If AzureFiles are configured, it will be mounted at /home. If Run-From-Pkg is configured the contents will be made available at /home/site/wwwroot.
   Note: It is possible for /home/site/wwwroot to point to a shared remote share. So copying contents to /home/site/wwwroot can be disruptive for other running instances. As a workaround /local/sitepackages will be used as a per-instance local storage where the zip will extracted before it gets mounted to /home/site/wwwwroot.

   Fixes #7252

Author: balag0

src/WebJobs.Script.WebHost/Management/IMeshServiceClient.cs

@@ -19,5 +19,7 @@ public interface IMeshServiceClient
         Task PublishContainerActivity(IEnumerable<ContainerFunctionExecutionActivity> activities);
 
         Task NotifyHealthEvent(ContainerHealthEventType healthEventType, Type source, string details);
+
+        Task CreateBindMount(string sourcePath, string targetPath);
     }
 }

src/WebJobs.Script.WebHost/Management/InstanceManager.cs

@@ -0,0 +1,70 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.IO.Compression;
+using Microsoft.Azure.WebJobs.Script.Diagnostics;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Management.LinuxSpecialization
+{
+    public class BashCommandHandler : IBashCommandHandler
+    {
+        public const string FileCommand = "file";
+
+        private readonly IMetricsLogger _metricsLogger;
+        private readonly ILogger<BashCommandHandler> _logger;
+
+        public BashCommandHandler(IMetricsLogger metricsLogger, ILogger<BashCommandHandler> logger)
+        {
+            _metricsLogger = metricsLogger ?? throw new ArgumentNullException(nameof(metricsLogger));
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        }
+
+        public (string, string, int) RunBashCommand(string command, string metricName)
+        {
+            try
+            {
+                using (_metricsLogger.LatencyEvent(metricName))
+                {
+                    var process = new Process
+                    {
+                        StartInfo = new ProcessStartInfo
+                        {
+                            FileName = "bash",
+                            Arguments = $"-c \"{command}\"",
+                            RedirectStandardOutput = true,
+                            RedirectStandardError = true,
+                            UseShellExecute = false,
+                            CreateNoWindow = true
+                        }
+                    };
+                    _logger.LogInformation($"Running: {process.StartInfo.FileName} {process.StartInfo.Arguments}");
+                    process.Start();
+                    var output = process.StandardOutput.ReadToEnd().Trim();
+                    var error = process.StandardError.ReadToEnd().Trim();
+                    process.WaitForExit();
+                    _logger.LogInformation($"Output: {output}");
+                    if (process.ExitCode != 0)
+                    {
+                        _logger.LogError(error);
+                    }
+                    else
+                    {
+                        _logger.LogInformation($"error: {error}");
+                    }
+                    _logger.LogInformation($"exitCode: {process.ExitCode}");
+                    return (output, error, process.ExitCode);
+                }
+            }
+            catch (Exception e)
+            {
+                _logger.LogError("Error running bash", e);
+            }
+
+            return (string.Empty, string.Empty, -1);
+        }
+    }
+}

src/WebJobs.Script.WebHost/Management/LinuxSpecialization/BashCommandHandler.cs

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Management.LinuxSpecialization
+{
+    public interface IBashCommandHandler
+    {
+        (string, string, int) RunBashCommand(string command, string metricName);
+    }
+}

src/WebJobs.Script.WebHost/Management/LinuxSpecialization/IBashCommandHandler.cs

@@ -0,0 +1,18 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using Microsoft.Azure.WebJobs.Script.WebHost.Models;
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Management.LinuxSpecialization
+{
+    public interface IRunFromPackageHandler
+    {
+        Task<string> Download(RunFromPackageContext pkgContext);
+
+        Task<bool> MountAzureFileShare(HostAssignmentContext assignmentContext);
+
+        Task<bool> ApplyBlobPackageContext(RunFromPackageContext pkgContext, string targetPath, bool azureFilesMounted,
+            bool throwOnFailure = true);
+    }
+}

src/WebJobs.Script.WebHost/Management/LinuxSpecialization/IRunFromPackageHandler.cs

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Management.LinuxSpecialization
+{
+    public interface IUnZipHandler
+    {
+        void UnzipPackage(string filePath, string scriptPath);
+    }
+}

src/WebJobs.Script.WebHost/Management/LinuxSpecialization/IUnZipHandler.cs

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.Azure.Storage.Blob;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Management.LinuxSpecialization
+{
+    public class RunFromPackageCloudBlockBlobService
+    {
+        public virtual async Task<bool> BlobExists(string url, string environmentVariableName, ILogger logger)
+        {
+            return await BlobExistsAsync(url, environmentVariableName, logger);
+        }
+
+        private static async Task<bool> BlobExistsAsync(string url, string environmentVariableName, ILogger logger)
+        {
+            bool exists = false;
+            await Utility.InvokeWithRetriesAsync(async () =>
+            {
+                try
+                {
+                    CloudBlockBlob blob = new CloudBlockBlob(new Uri(url));
+                    exists = await blob.ExistsAsync();
+                }
+                catch (Exception e)
+                {
+                    logger.LogError(e, $"Failed to check if zip url blob exists");
+                    throw;
+                }
+            }, maxRetries: 2, retryInterval: TimeSpan.FromSeconds(0.3));
+
+            if (!exists)
+            {
+                logger.LogWarning($"{environmentVariableName} points to an empty location. Function app has no content.");
+            }
+
+            return exists;
+        }
+    }
+}