Implements "ef dbcontext script"

and PS>Script-DbContext

fixes issue dotnet#10378

src/EFCore.Design/Design/Internal/DbContextOperations.cs

@@ -94,6 +94,20 @@ public virtual void DropDatabase([CanBeNull] string contextType)
             }
         }
 
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public virtual string ScriptDbContext([CanBeNull] string contextType)
+        {
+            using (var context = CreateContext(contextType))
+            {
+                return context.Database.GenerateCreateScript();
+            }
+        }
+
         /// <summary>
         ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
         ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.Design/Design/OperationExecutor.cs

@@ -508,6 +508,37 @@ public DropDatabase(
         private void DropDatabaseImpl(string contextType)
             => _contextOperations.Value.DropDatabase(contextType);
 
+        /// <summary>
+        ///     Represents an operation to generate a SQL script from the DbContext.
+        /// </summary>
+        public class ScriptDbContext : OperationBase
+        {
+            /// <summary>
+            ///     <para>Initializes a new instance of the <see cref="ScriptDbContext" /> class.</para>
+            ///     <para>The arguments supported by <paramref name="args" /> are:</para>
+            ///     <para><c>contextType</c>--The <see cref="DbContext" /> to use.</para>
+            /// </summary>
+            /// <param name="executor"> The operation executor. </param>
+            /// <param name="resultHandler"> The <see cref="IOperationResultHandler" />. </param>
+            /// <param name="args"> The operation arguments. </param>
+            public ScriptDbContext(
+                [NotNull] OperationExecutor executor,
+                [NotNull] object resultHandler,
+                [NotNull] IDictionary args)
+                : base(resultHandler)
+            {
+                Check.NotNull(executor, nameof(executor));
+                Check.NotNull(args, nameof(args));
+
+                var contextType = (string)args["contextType"];
+
+                Execute(() => executor.ScriptDbContextImpl(contextType));
+            }
+        }
+
+        private string ScriptDbContextImpl(string contextType)
+            => _contextOperations.Value.ScriptDbContext(contextType);
+
         /// <summary>
         ///     Represents an operation.
         /// </summary>

src/EFCore.Tools/EntityFrameworkCore.PowerShell2.psd1.in

@@ -64,6 +64,7 @@
         'Get-DbContext',
         'Remove-Migration',
         'Scaffold-DbContext',
+        'Script-DbContext',
         'Script-Migration',
         'Update-Database'
     )

src/EFCore.Tools/EntityFrameworkCore.psd1.in

@@ -67,6 +67,7 @@
         'Get-DbContext',
         'Remove-Migration',
         'Scaffold-DbContext',
+        'Script-DbContext',
         'Script-Migration',
         'Update-Database'
     )

src/EFCore.Tools/tools/EntityFrameworkCore.PowerShell2.psm1

@@ -37,6 +37,11 @@ function Scaffold-DbContext
     throw $versionErrorMessage
 }
 
+function Script-DbContext
+{
+    throw $versionErrorMessage
+}
+
 function Script-Migration
 {
     throw $versionErrorMessage

src/EFCore.Tools/tools/EntityFrameworkCore.psm1

@@ -366,6 +366,77 @@ function Scaffold-DbContext
     ShowConsole
 }
 
+#
+# Script-DbContext
+#
+
+Register-TabExpansion Script-DbContext @{
+    Context = { param($x) GetContextTypes $x.Project $x.StartupProject }
+    Project = { GetProjects }
+    StartupProject = { GetProjects }
+}
+
+<#
+.SYNOPSIS
+    Generates a SQL script from current DbContext.
+
+.DESCRIPTION
+    Generates a SQL script from current DbContext.
+
+.PARAMETER Output
+    The file to write the result to.
+
+.PARAMETER Context
+    The DbContext to use.
+
+.PARAMETER Project
+    The project to use.
+
+.PARAMETER StartupProject
+    The startup project to use. Defaults to the solution's startup project.
+
+.LINK
+    about_EntityFrameworkCore
+#>
+function Script-DbContext
+{
+    [CmdletBinding(PositionalBinding = $false)]
+    param(
+        [string] $Output,
+        [string] $Context,
+        [string] $Project,
+        [string] $StartupProject)
+
+    $dteProject = GetProject $Project
+    $dteStartupProject = GetStartupProject $StartupProject $dteProject
+
+    if (!$Output)
+    {
+        $intermediatePath = GetIntermediatePath $dteProject
+        if (![IO.Path]::IsPathRooted($intermediatePath))
+        {
+            $projectDir = GetProperty $dteProject.Properties 'FullPath'
+            $intermediatePath = Join-Path $projectDir $intermediatePath -Resolve | Convert-Path
+        }
+
+        $scriptFileName = [IO.Path]::ChangeExtension([IO.Path]::GetRandomFileName(), '.sql')
+        $Output = Join-Path $intermediatePath $scriptFileName
+    }
+    elseif (![IO.Path]::IsPathRooted($Output))
+    {
+        $Output = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($Output)
+    }
+
+    $params = 'dbcontext', 'script', '--output', $Output
+
+    $params += GetParams $Context
+
+    EF $dteProject $dteStartupProject $params
+
+    $DTE.ItemOperations.OpenFile($Output) | Out-Null
+    ShowConsole
+}
+
 #
 # Script-Migration
 #

src/EFCore.Tools/tools/about_EntityFrameworkCore.help.txt

@@ -30,6 +30,8 @@ LONG DESCRIPTION
 
         Scaffold-DbContext          Scaffolds a DbContext and entity types for a database.
 
+        Script-DbContext            Generates a SQL script from the current DbContext. 
+
         Script-Migration            Generates a SQL script from migrations.
 
         Update-Database             Updates the database to a specified migration.
@@ -40,5 +42,6 @@ SEE ALSO
     Get-DbContext
     Remove-Migration
     Scaffold-DbContext
+    Script-DbContext
     Script-Migration
     Update-Database

src/ef/Commands/DbContextCommand.cs

@@ -15,6 +15,7 @@ public override void Configure(CommandLineApplication command)
             command.Command("info", new DbContextInfoCommand().Configure);
             command.Command("list", new DbContextListCommand().Configure);
             command.Command("scaffold", new DbContextScaffoldCommand().Configure);
+            command.Command("script", new DbContextScriptCommand().Configure);
 
             base.Configure(command);
         }

src/ef/Commands/DbContextScriptCommand.Configure.cs

@@ -0,0 +1,22 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.DotNet.Cli.CommandLine;
+using Microsoft.EntityFrameworkCore.Tools.Properties;
+
+namespace Microsoft.EntityFrameworkCore.Tools.Commands
+{
+    internal partial class DbContextScriptCommand : ContextCommandBase
+    {
+        private CommandOption _output;
+
+        public override void Configure(CommandLineApplication command)
+        {
+            command.Description = Resources.MigrationsScriptDescription;
+
+            _output = command.Option("-o|--output <FILE>", Resources.OutputDescription);
+
+            base.Configure(command);
+        }
+    }
+}

src/ef/Commands/DbContextScriptCommand.cs

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Text;
+using Microsoft.EntityFrameworkCore.Tools.Properties;
+
+namespace Microsoft.EntityFrameworkCore.Tools.Commands
+{
+    // ReSharper disable once ArrangeTypeModifiers
+    internal partial class DbContextScriptCommand
+    {
+        protected override int Execute()
+        {
+            var sql = CreateExecutor().ScriptDbContext(
+                Context.Value());
+
+            if (!_output.HasValue())
+            {
+                Reporter.WriteData(sql);
+            }
+            else
+            {
+                var output = _output.Value();
+                if (WorkingDir.HasValue())
+                {
+                    output = Path.Combine(WorkingDir.Value(), output);
+                }
+
+                var directory = Path.GetDirectoryName(output);
+                if (!string.IsNullOrEmpty(directory))
+                {
+                    Directory.CreateDirectory(directory);
+                }
+
+                Reporter.WriteVerbose(Resources.WritingFile(_output.Value()));
+                File.WriteAllText(output, sql, Encoding.UTF8);
+            }
+
+            return base.Execute();
+        }
+    }
+}

src/ef/IOperationExecutor.cs

@@ -30,5 +30,7 @@ IDictionary ScaffoldContext(
             bool useDatabaseNames);
 
         string ScriptMigration(string fromMigration, string toMigration, bool idempotent, string contextType);
+
+        string ScriptDbContext(string contextType);
     }
 }

src/ef/OperationExecutorBase.cs

@@ -179,5 +179,13 @@ public string ScriptMigration(
                     ["idempotent"] = idempotent,
                     ["contextType"] = contextType
                 });
+
+        public string ScriptDbContext(string contextType)
+            => InvokeOperation<string>(
+                "ScriptDbContext",
+                new Dictionary<string, object>
+                {
+                    ["contextType"] = contextType
+                });
     }
 }

src/ef/Properties/Resources.resx

@@ -315,4 +315,7 @@
   <data name="WorkingDirDescription" xml:space="preserve">
     <value>The working directory of the tool invoking this command.</value>
   </data>
+  <data name="DbContextScriptDescription" xml:space="preserve">
+    <value>Generate a script to create all tables for the DbContext.</value>
+  </data>
 </root>

test/ef.Tests/SimpleProjectTest.cs

@@ -140,6 +140,20 @@ public void ScriptMigration()
             }
         }
 
+        [Fact]
+        public void ScriptDbContext()
+        {
+            try
+            {
+                var sql = _project.Executor.ScriptDbContext("SimpleContext");
+                Assert.NotEmpty(sql);
+            }
+            catch (WrappedException ex)
+            {
+                throw new WrappedXunitException(ex);
+            }
+        }
+
         [Fact]
         public void GetContextTypes()
         {
@@ -229,6 +243,13 @@ protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
                                     {
                                         optionsBuilder.UseSqlServer(""Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=SimpleProject.SimpleContext;Integrated Security=True"");
                                     }
+
+                                    internal DbSet<Simple> Simples { get; set; }
+                                }
+
+                                internal class Simple
+                                {
+                                    public int Id { get; set; }
                                 }
 
                                 namespace Migrations