Refactor Linux-specific options setup into ScriptApplicationHostOptionsSetup (#7366)

Author: pgombar

src/WebJobs.Script.WebHost/Configuration/LinuxScriptApplicationHostOptionsSetup.cs

@@ -3,8 +3,12 @@
 
 using System;
 using System.IO;
+using System.Threading;
+using Microsoft.Azure.Storage.Blob;
 using Microsoft.Azure.WebJobs.Script.Configuration;
+using Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics;
 using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using static Microsoft.Azure.WebJobs.Script.EnvironmentSettingNames;
 
@@ -65,14 +69,99 @@ public void Configure(string name, ScriptApplicationHostOptions options)
                 options.IsStandbyConfiguration = true;
             }
 
-            options.IsFileSystemReadOnly = IsZipDeployment();
+            options.IsFileSystemReadOnly = IsZipDeployment(out bool isScmRunFromPackage);
+            options.IsScmRunFromPackage = isScmRunFromPackage;
         }
 
-        private bool IsZipDeployment()
+        private bool IsZipDeployment(out bool isScmRunFromPackage)
         {
-            return Utility.IsValidZipSetting(_environment.GetEnvironmentVariable(AzureWebsiteZipDeployment)) ||
+            // Check app settings for run from package.
+            bool runFromPkgConfigured = Utility.IsValidZipSetting(_environment.GetEnvironmentVariable(AzureWebsiteZipDeployment)) ||
                 Utility.IsValidZipSetting(_environment.GetEnvironmentVariable(AzureWebsiteAltZipDeployment)) ||
                 Utility.IsValidZipSetting(_environment.GetEnvironmentVariable(AzureWebsiteRunFromPackage));
+
+            if (!_environment.IsLinuxConsumption())
+            {
+                isScmRunFromPackage = false;
+                // This check is strong enough for SKUs other than Linux Consumption.
+                return runFromPkgConfigured;
+            }
+
+            // The following logic only applies to Linux Consumption, since currently SCM_RUN_FROM_PACKAGE is always set even if we are not using it.
+            if (runFromPkgConfigured)
+            {
+                isScmRunFromPackage = false;
+                return true;
+            }
+
+            // If SCM_RUN_FROM_PACKAGE is set to a valid value and the blob exists, it's a zip deployment.
+            var url = _environment.GetEnvironmentVariable(ScmRunFromPackage);
+            if (string.IsNullOrEmpty(url))
+            {
+                LinuxContainerEventGenerator.LogEvent(message: $"{nameof(ScmRunFromPackage)} is empty.", source: nameof(ScriptApplicationHostOptionsSetup));
+                isScmRunFromPackage = false;
+                return false;
+            }
+
+            if (Utility.TryCleanUrl(url, out string cleanedUrl))
+            {
+                LinuxContainerEventGenerator.LogEvent(message: $"{nameof(ScmRunFromPackage)} = {cleanedUrl}", source: nameof(ScriptApplicationHostOptionsSetup));
+            }
+
+            var isValidZipSetting = Utility.IsValidZipSetting(url);
+            LinuxContainerEventGenerator.LogEvent(message: $"{nameof(ScmRunFromPackage)} isValidZipSetting = {isValidZipSetting}", source: nameof(ScriptApplicationHostOptionsSetup));
+
+            if (!isValidZipSetting)
+            {
+                isScmRunFromPackage = false;
+                // Return early so we don't call storage if it isn't absolutely necessary.
+                return false;
+            }
+
+            var blobExists = BlobExists(url);
+            LinuxContainerEventGenerator.LogEvent(message: $"{nameof(ScmRunFromPackage)} blobExists = {blobExists}", source: nameof(ScriptApplicationHostOptionsSetup));
+
+            bool scmRunFromPkgConfigured = isValidZipSetting && blobExists;
+            isScmRunFromPackage = scmRunFromPkgConfigured;
+            return scmRunFromPkgConfigured;
+        }
+
+        public virtual bool BlobExists(string url)
+        {
+            if (string.IsNullOrEmpty(url))
+            {
+                return false;
+            }
+
+            try
+            {
+                CloudBlockBlob blob = new CloudBlockBlob(new Uri(url));
+
+                int attempt = 0;
+                while (true)
+                {
+                    try
+                    {
+                        return blob.Exists();
+                    }
+                    catch (Exception ex) when (!ex.IsFatal())
+                    {
+                        LinuxContainerEventGenerator.LogEvent(message: $"Exception when checking if {nameof(ScmRunFromPackage)} blob exists", e: ex,
+                            logLevel: LogLevel.Error, source: nameof(ScriptApplicationHostOptionsSetup));
+                        if (++attempt > 2)
+                        {
+                            return false;
+                        }
+                        Thread.Sleep(TimeSpan.FromSeconds(0.3));
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                LinuxContainerEventGenerator.LogEvent(message: $"Failed to check status of {nameof(ScmRunFromPackage)}", e: ex,
+                    logLevel: LogLevel.Error, source: nameof(ScriptApplicationHostOptionsSetup));
+                return false;
+            }
         }
 
         public void Dispose()

src/WebJobs.Script.WebHost/Configuration/ScriptApplicationHostOptionsSetup.cs

@@ -9,6 +9,7 @@ namespace Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics
     internal class LinuxContainerEventGenerator : LinuxEventGenerator
     {
         private const int MaxDetailsLength = 10000;
+        private static readonly Lazy<LinuxContainerEventGenerator> _Lazy = new Lazy<LinuxContainerEventGenerator>(() => new LinuxContainerEventGenerator(SystemEnvironment.Instance));
         private readonly Action<string> _writeEvent;
         private readonly bool _consoleEnabled = true;
         private readonly IEnvironment _environment;
@@ -37,6 +38,8 @@ public LinuxContainerEventGenerator(IEnvironment environment, Action<string> wri
 
         public static string AzureMonitorEventRegex { get; } = $"{ScriptConstants.LinuxAzureMonitorEventStreamName} (?<Level>[0-6]),(?<ResourceId>[^,]*),(?<OperationName>[^,]*),(?<Category>[^,]*),(?<RegionName>[^,]*),\"(?<Properties>[^,]*)\",(?<ContainerName>[^,\"]*),(?<TenantId>[^,\"]*),(?<EventTimestamp>[^,]+)";
 
+        public static LinuxContainerEventGenerator LinuxContainerEventGeneratorInstance { get { return _Lazy.Value; } }
+
         private string StampName
         {
             get
@@ -116,5 +119,26 @@ public static void LogUnhandledException(Exception e)
                 SystemEnvironment.Instance.GetSlotName() ?? string.Empty,
                 DateTime.UtcNow);
         }
+
+        public static void LogEvent(string message, Exception e = null, LogLevel logLevel = LogLevel.Debug, string source = null)
+        {
+            LinuxContainerEventGeneratorInstance.LogFunctionTraceEvent(
+                level: logLevel,
+                subscriptionId: SystemEnvironment.Instance.GetSubscriptionId() ?? string.Empty,
+                appName: SystemEnvironment.Instance.GetAzureWebsiteUniqueSlotName() ?? string.Empty,
+                functionName: string.Empty,
+                eventName: string.Empty,
+                source: source ?? nameof(LogEvent),
+                details: e?.ToString() ?? string.Empty,
+                summary: message,
+                exceptionType: e?.GetType().ToString() ?? string.Empty,
+                exceptionMessage: e?.ToString() ?? string.Empty,
+                functionInvocationId: string.Empty,
+                hostInstanceId: string.Empty,
+                activityId: string.Empty,
+                runtimeSiteName: SystemEnvironment.Instance.GetRuntimeSiteName() ?? string.Empty,
+                slotName: SystemEnvironment.Instance.GetSlotName() ?? string.Empty,
+                eventTimestamp: DateTime.UtcNow);
+        }
     }
 }

src/WebJobs.Script.WebHost/Diagnostics/LinuxContainerEventGenerator.cs

@@ -163,15 +163,6 @@ public static void AddWebJobsScriptHost(this IServiceCollection services, IConfi
 
             // Configuration
             services.ConfigureOptions<ScriptApplicationHostOptionsSetup>();
-            services.AddSingleton<IConfigureOptions<ScriptApplicationHostOptions>>(p =>
-            {
-                var environment = p.GetService<IEnvironment>();
-                if (environment.IsLinuxConsumption())
-                {
-                    return new LinuxScriptApplicationHostOptionsSetup(environment);
-                }
-                return LinuxScriptApplicationHostOptionsSetup.NullInstance;
-            });
             services.ConfigureOptions<StandbyOptionsSetup>();
             services.ConfigureOptions<LanguageWorkerOptionsSetup>();
             services.ConfigureOptionsWithChangeTokenSource<AppServiceOptions, AppServiceOptionsSetup, SpecializationChangeTokenSource<AppServiceOptions>>();