Expose Ports, Output Dockerfile without building the image (dry run)

DockerfileTemplate.cs

@@ -1,15 +1,22 @@
-namespace Brthor.Dockerize
+using System.Linq;
+
+// ReSharper disable once CheckNamespace
+namespace Brthor.Dockerize
 {
     public static class DockerfileTemplate
     {
         public static string Generate(DockerizeConfiguration config, string outputBinaryName)
         {
-            var addUser = config.Username == null 
+            var addUser = string.IsNullOrWhiteSpace(config.Username)
                 ? ""
                 : $@"RUN groupadd -r {config.Username} && useradd --no-log-init -r -g {config.Username} {config.Username}
 RUN chown {config.Username}:{config.Username} /projectBinaries
 USER {config.Username}:{config.Username}";
 
+            var ports = config.ExposedPorts == null
+                ? ""
+                : string.Join("\n", config.ExposedPorts.Select(port => $"EXPOSE {port}"));
+
             var chownOnAdd = config.Username == null
                 ? ""
                 : $"--chown={config.Username}:{config.Username} ";
@@ -22,6 +29,8 @@ RUN mkdir /projectBinaries
 ADD {chownOnAdd}./publish/ /projectBinaries/
 WORKDIR /projectBinaries/
 
+{ports}
+
 CMD /projectBinaries/{outputBinaryName}
 ";
             return dockerfileContent;

DockerizeConfiguration.cs

@@ -1,5 +1,7 @@
-using Microsoft.DotNet.Cli.Utils;
+using System.Collections.Generic;
+using Microsoft.DotNet.Cli.Utils;
 
+// ReSharper disable once CheckNamespace
 namespace Brthor.Dockerize
 {
     public class DockerizeConfiguration
@@ -22,22 +24,36 @@ public class DockerizeConfiguration
         public string BuildConfiguration { get; }
 
         public string Username { get; }
+
+        public List<string> ExposedPorts { get; }
+
+        public bool DryRun { get; }
 
-        public DockerizeConfiguration(string projectName, string configuration, string tag, string baseRid, string baseImage, 
-            string username=null)
+        public DockerizeConfiguration(
+            string projectName, 
+            string configuration, 
+            string tag, 
+            string baseRid, 
+            string baseImage, 
+            bool dryRun,
+            string username, 
+            List<string> exposedPorts)
         {
             GeneratedImageTag = tag ?? projectName;
             BaseRid = baseRid ?? "linux-x64";
             BaseImage = baseImage ?? "microsoft/dotnet:2.0-runtime";
             BuildConfiguration = configuration ?? "Release";
+
+            DryRun = dryRun;
             Username = username;
+            ExposedPorts = exposedPorts;
 
             Reporter.Output.WriteLine($"Dockerize.NET".Blue());
             Reporter.Output.WriteLine("Base Docker Image: ".White() +  $"{BaseImage}".Green());
             Reporter.Output.WriteLine("Base Rid of Docker Image: ".White() + $"{BaseRid}".Green());
             Reporter.Output.WriteLine("Tag: ".White() + $"{GeneratedImageTag}".Green());
 
-            if (Username != null)
+            if (!string.IsNullOrWhiteSpace(Username))
                 Reporter.Output.WriteLine("Username: ".White() + $"{Username}".Green());
         }
     }

Program.cs

@@ -5,11 +5,12 @@
 using Microsoft.DotNet.Cli.Utils;
 using Microsoft.Extensions.CommandLineUtils;
 
+// ReSharper disable once CheckNamespace
 namespace Brthor.Dockerize
 {
-    class Program
+    public static class Program
     {
-        static int Main(string[] args)
+        public static int Main(string[] args)
         {
             var commandLineApplication =
                 new CommandLineApplication(throwOnUnexpectedArg: false);
@@ -49,11 +50,29 @@ static int Main(string[] args)
                 "It is recommended to run production containers not as root for security.",
                 CommandOptionType.SingleValue);
 
+            var exposedPorts = commandLineApplication.Option(
+                "-p |--port <port>",
+                "Expose one or more ports in your docker container. Expose multiple by passing `-p` multiple times.",
+                CommandOptionType.MultipleValue);
+
+            var dryRun = commandLineApplication.Option(
+                "-n |--dry-run",
+                "Outputs the generated dockerfile to stdout. Does not call `docker build`. Still calls `dotnet publish`",
+                CommandOptionType.NoValue);
+
             commandLineApplication.HelpOption("-? | -h | --help");
             commandLineApplication.OnExecute(() =>
             {
                 var projectName = GetProjectName(Environment.CurrentDirectory, project);
-                var config = new DockerizeConfiguration(projectName, configuration.Value(), tag.Value(), baseRid.Value(), baseImage.Value(), username.Value());
+                var config = new DockerizeConfiguration(
+                    projectName, 
+                    configuration.HasValue() ? configuration.Value() : null, 
+                    tag.HasValue() ? tag.Value() : null, 
+                    baseRid.HasValue() ? baseRid.Value() : null, 
+                    baseImage.HasValue() ? baseImage.Value() : null, 
+                    dryRun.HasValue(),
+                    username.HasValue() ? username.Value() : null, 
+                    exposedPorts.HasValue() ? exposedPorts.Values : null);
 
                 return Run(config);
             });
@@ -83,8 +102,8 @@ private static string GetProjectName(string currentDirectory, CommandOption proj
             return Path.GetFileNameWithoutExtension(projectFilePath);
         }
 
-        static int Run(DockerizeConfiguration config){
-
+        private static int Run(DockerizeConfiguration config)
+        {
             var projectDirectory = Environment.CurrentDirectory;
             var dockerizeBaseDir = Path.Combine(projectDirectory, "bin", "dockerize");
             var publishOutDirectory = Path.Combine(dockerizeBaseDir, "publish");
@@ -121,6 +140,12 @@ static int Run(DockerizeConfiguration config){
                 Path.GetFileNameWithoutExtension(publishOutputDepsJsons.Single()).Replace(".deps", "");
 
             var dockerfile = DockerfileTemplate.Generate(config, outputBinaryName);
+
+            if (config.DryRun)
+            {
+                Console.WriteLine(dockerfile);
+                return 0;
+            }
 
             File.WriteAllText(dockerfilePath, dockerfile);