[TW] Add docstrings for Dockerfile generator (#120)

* Add docstrings.

* Update DevKit image for Ubuntu agent.

configs/devkit/linux/agent/Ubuntu.devkit.Dockerfile

@@ -10,7 +10,18 @@ FROM ${teamCityImage}
 
 USER root
 
-RUN rm -rf /opt/buildagent/*
+# Remove agent code sequentially to work around the inability to delete volumes from the base image.
+RUN rm -rf '/opt/buildagent/bin' && \
+    rm -rf '/opt/buildagent/tools' && \
+    rm -rf '/opt/buildagent/system' && \
+    rm -rf '/opt/buildagent/plugins' && \
+    rm -rf '/opt/buildagent/temp' && \
+    rm -rf '/opt/buildagent/work' && \
+    rm -rf '/opt/buildagent/lib' && \
+    rm -rf '/opt/buildagent/conf' && \
+    rm -rf '/opt/buildagent/launcher' && \
+    rm -rf '/data/teamcity_agent/conf'
+
 USER buildagent
 
 CMD ["sleep", "infinity"]

tool/TeamCity.Docker/ConfigurationExplorer.cs

@@ -9,6 +9,9 @@ namespace TeamCity.Docker
     using IoC;
     using Model;
 
+    /// <summary>
+    /// Locates configuration files for Docker Images.
+    /// </summary>
     internal class ConfigurationExplorer : IConfigurationExplorer
     {
         [NotNull] private readonly ILogger _logger;
@@ -21,7 +24,7 @@ public ConfigurationExplorer(
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
             _fileSystem = fileSystem ?? throw new ArgumentNullException(nameof(fileSystem));
         }
-
+        
         public Result<IEnumerable<Template>> Explore(string sourcePath, IEnumerable<string> configurationFiles)
         {
             if (sourcePath == null)
@@ -95,9 +98,10 @@ private IEnumerable<Template> GetConfigurations([NotNull] string sourcePath, [No
                     var ignore = new List<string>();
                     if (_fileSystem.IsFileExist(dockerignoreTemplatePath))
                     {
+                        // Add .Dockerignore files
                         ignore.AddRange(_fileSystem.ReadLines(dockerignoreTemplatePath));
                     }
-
+                    
                     yield return new Template(_fileSystem.ReadLines(dockerfileTemplate).ToImmutableList(), variants.AsReadOnly(), ignore.AsReadOnly());
                 }
             }

tool/TeamCity.Docker/DockerGraphFactory.cs

@@ -49,6 +49,7 @@ public Result<IGraph<IArtifact, Dependency>> Create(IEnumerable<Template> templa
             var nodeDict = new Dictionary<string, INode<IArtifact>>();
             foreach (var template in templates)
             {
+                // "variants" are different Dockerfile.config files for the template
                 foreach (var variant in template.Variants)
                 {
                     var lines = _contentParser.Parse(template.Lines, variant.Variables).ToImmutableList();

tool/TeamCity.Docker/IConfigurationExplorer.cs

@@ -4,8 +4,17 @@
     using IoC;
     using Model;
 
+    /// <summary>
+    /// Describes the contract for locating template files for Docker images.
+    /// </summary>
     internal interface IConfigurationExplorer
     {
+        /// <summary>
+        /// Locates configuration files within the given path.
+        /// </summary>
+        /// <param name="sourcePath">path to directory with the templates of Dockerfiles (configs)</param>
+        /// <param name="configurationFiles">list of files with configuration properties within source path (.config files)</param>
+        /// <returns>list of templates (templates, config values)</returns>
         Result<IEnumerable<Template>> Explore([NotNull] string sourcePath, [NotNull] IEnumerable<string> configurationFiles);
     }
 }

tool/TeamCity.Docker/Model/Template.cs

@@ -10,6 +10,12 @@ internal readonly struct Template
         [NotNull] public readonly IEnumerable<Variant> Variants;
         [NotNull] public readonly IReadOnlyCollection<string> Ignore;
 
+        /// <summary>
+        /// Creates object describing configuration for Dockerfile.
+        /// </summary>
+        /// <param name="lines">Content of the template Dockerfile.</param>
+        /// <param name="variants">Different configuration options (.config files)</param>
+        /// <param name="ignore">Content of .Dockerignore</param>
         public Template([NotNull] IReadOnlyCollection<string> lines, [NotNull] IReadOnlyCollection<Variant> variants, [NotNull] IReadOnlyCollection<string> ignore)
         {
             Lines = lines ?? throw new ArgumentNullException(nameof(lines));