Integrate with GitHub job summaries (closes #7)

README.md

@@ -60,6 +60,8 @@ If you have multiple kickflip flows in the same workflow (for example deploying
     kickflip github pull-request --repo <owner>/<repo> --ref <ref> --token <token> --action-name staging
     kickflip github pull-request --repo <owner>/<repo> --ref <ref> --token <token> --action-name production
 
+When running inside GitHub Actions, kickflip also writes the deployment change summary to the [job summary](https://github.blog/2022-05-09-supercharging-github-actions-with-job-summaries/) so it appears on the workflow run page. This happens automatically whenever the `GITHUB_STEP_SUMMARY` environment variable is present (which GitHub Actions sets for every step), in addition to posting the pull request comment.
+
 ## Github Actions
 
 Github Actions `actions/checkout@v4` by default performs a shallow clone of the repo. In order for kickflip to work out all the changes it requires that a full clone be made. This can be achieve by:

src/kickflip.Tests/GithubJobSummaryServiceTests.cs

@@ -0,0 +1,71 @@
+using kickflip.Services;
+
+namespace kickflip.Tests;
+
+public class GithubJobSummaryServiceTests
+{
+    [Fact]
+    public void IsAvailable_ReturnsFalse_WhenPathIsNullOrEmpty()
+    {
+        Assert.False(new GithubJobSummaryService(null).IsAvailable);
+        Assert.False(new GithubJobSummaryService("").IsAvailable);
+        Assert.False(new GithubJobSummaryService("   ").IsAvailable);
+    }
+
+    [Fact]
+    public void IsAvailable_ReturnsTrue_WhenPathProvided()
+    {
+        Assert.True(new GithubJobSummaryService("/tmp/summary.md").IsAvailable);
+    }
+
+    [Fact]
+    public async Task AppendSummaryAsync_WritesContentToFile()
+    {
+        var path = Path.GetTempFileName();
+        try
+        {
+            var service = new GithubJobSummaryService(path);
+            var result = await service.AppendSummaryAsync("## Hello\ncontent");
+
+            Assert.True(result);
+            var written = await File.ReadAllTextAsync(path);
+            Assert.Contains("## Hello", written);
+            Assert.Contains("content", written);
+        }
+        finally
+        {
+            File.Delete(path);
+        }
+    }
+
+    [Fact]
+    public async Task AppendSummaryAsync_AppendsToExistingContent()
+    {
+        var path = Path.GetTempFileName();
+        try
+        {
+            await File.WriteAllTextAsync(path, "existing\n");
+
+            var service = new GithubJobSummaryService(path);
+            await service.AppendSummaryAsync("added");
+
+            var written = await File.ReadAllTextAsync(path);
+            Assert.Contains("existing", written);
+            Assert.Contains("added", written);
+            Assert.True(written.IndexOf("existing", StringComparison.Ordinal) <
+                        written.IndexOf("added", StringComparison.Ordinal));
+        }
+        finally
+        {
+            File.Delete(path);
+        }
+    }
+
+    [Fact]
+    public async Task AppendSummaryAsync_ReturnsFalse_WhenNotAvailable()
+    {
+        var service = new GithubJobSummaryService(null);
+        var result = await service.AppendSummaryAsync("content");
+        Assert.False(result);
+    }
+}

src/kickflip/Program.cs

@@ -230,6 +230,13 @@ private static async Task<int> HandleGithubPullRequest(string localPath, FindMod
             }
 
             Console.WriteLine("Github Pull Request Comment Successful!");
+
+            var jobSummaryService = new GithubJobSummaryService(Environment.GetEnvironmentVariable("GITHUB_STEP_SUMMARY"));
+            if (await jobSummaryService.AppendSummaryAsync(sectionContent))
+            {
+                Console.WriteLine("Github Job Summary updated!");
+            }
+
             return (int) ExitCodes.Success;
         }
     }

src/kickflip/Services/GithubJobSummaryService.cs

@@ -0,0 +1,40 @@
+namespace kickflip.Services;
+
+/// <summary>
+/// Writes deployment change summaries to the GitHub Actions job summary.
+/// GitHub Actions exposes the summary as a file via the GITHUB_STEP_SUMMARY
+/// environment variable. Anything appended to that file (as markdown) is
+/// rendered on the workflow run's summary page.
+/// See https://github.blog/2022-05-09-supercharging-github-actions-with-job-summaries/
+/// </summary>
+public class GithubJobSummaryService
+{
+    private readonly string? _summaryFilePath;
+
+    public GithubJobSummaryService(string? summaryFilePath)
+    {
+        _summaryFilePath = summaryFilePath;
+    }
+
+    /// <summary>
+    /// Whether a job summary file is available to write to. This is only the
+    /// case when running inside GitHub Actions.
+    /// </summary>
+    public bool IsAvailable => !string.IsNullOrWhiteSpace(_summaryFilePath);
+
+    /// <summary>
+    /// Appends the given markdown content to the GitHub Actions job summary.
+    /// Returns false when no job summary is available (i.e. not running in
+    /// GitHub Actions).
+    /// </summary>
+    public async Task<bool> AppendSummaryAsync(string content)
+    {
+        if (!IsAvailable)
+        {
+            return false;
+        }
+
+        await File.AppendAllTextAsync(_summaryFilePath!, content + Environment.NewLine);
+        return true;
+    }
+}