Async install of Portable Git

[StanleyGoldman]

Note: This pull request targets enhancements/async-git-setup-rollup #561

Presently

The installation of portable git is currently a synchronous process initiated from ApplicationManagerBase.

Unity/src/GitHub.Api/Application/ApplicationManagerBase.cs

Lines 46 to 82 in a1ec1cb

	public void Run(bool firstRun)
	{
	new ActionTask(SetupGit())
	.Then(RestartRepository)
	.ThenInUI(InitializeUI)
	.Start();
	}
	private async Task SetupGit()
	{
	Logger.Trace("Run - CurrentDirectory {0}", NPath.CurrentDirectory);
	if (Environment.GitExecutablePath == null)
	{
	Environment.GitExecutablePath = await DetermineGitExecutablePath();
	Logger.Trace("Environment.GitExecutablePath \"{0}\" Exists:{1}", Environment.GitExecutablePath, Environment.GitExecutablePath.FileExists());
	if (Environment.IsWindows)
	{
	var credentialHelper = await GitClient.GetConfig("credential.helper", GitConfigSource.Global).StartAwait();
	if (!string.IsNullOrEmpty(credentialHelper))
	{
	Logger.Trace("Windows CredentialHelper: {0}", credentialHelper);
	}
	else
	{
	Logger.Warning("No Windows CredentialHeloper found: Setting to wincred");
	await GitClient.SetConfig("credential.helper", "wincred", GitConfigSource.Global).StartAwait();
	}
	}
	}
	Environment.User.Initialize(GitClient);
	}

Unity/src/GitHub.Api/Application/ApplicationManagerBase.cs

Lines 139 to 158 in a1ec1cb

	private async Task<NPath> DetermineGitExecutablePath(ProgressReport progress = null)
	{
	var gitExecutablePath = SystemSettings.Get(Constants.GitInstallPathKey)?.ToNPath();
	if (gitExecutablePath != null && gitExecutablePath.FileExists())
	{
	Logger.Trace("Using git install path from settings");
	return gitExecutablePath;
	}
	var gitInstaller = new GitInstaller(Environment, CancellationToken);
	var setupDone = await gitInstaller.SetupIfNeeded(progress?.Percentage, progress?.Remaining);
	if (setupDone)
	{
	Logger.Trace("Setup performed using new path");
	return gitInstaller.GitExecutablePath;
	}
	Logger.Trace("Finding git install path");
	return await GitClient.FindGitInstallation().SafeAwait();
	}

It's responsibilities are as follows.
This process is currently linear & synchronous, running on the main thread.

• Setup Git
  • Determine where git is installed
    • Get the value from settings, if it exists use that
    • If the previous step did not produce a path
      • Check for the existence of our Portable Git folder
        • Check that the git exec is present
        • Check that the git lfs exec is present
        • Check that the git-lfs exec matches the expected MD5
        • Attempt to extract git and git-lfs if the zip is present
        • If this process is successful use that path
    • If the previous step did not produce a path
      • And we are not on windows and /usr/local/bin/git exists, use that
    • If the previous step did not produce a path
      • run the system where/which command to find git.
  • Set Environment.GitExecutablePath
  • If on Windows, check that the credential helper is set to wincred
• Initialize the User with GitClient
• Restart Repository
• Initialize UI

Pull Request

Unity/src/GitHub.Api/Application/ApplicationManagerBase.cs

Lines 46 to 117 in e6762b5

	public void Run(bool firstRun)
	{
	Logger.Trace("Run - CurrentDirectory {0}", NPath.CurrentDirectory);
	var afterGitSetup = new ActionTask(CancellationToken, RestartRepository)
	.ThenInUI(InitializeUI);
	//GitClient.GetConfig cannot be called until there is a git path set so it is wrapped in an ActionTask
	var windowsCredentialSetup = new ActionTask(CancellationToken, () => {
	GitClient.GetConfig("credential.helper", GitConfigSource.Global).Then((b, credentialHelper) => {
	if (!string.IsNullOrEmpty(credentialHelper))
	{
	Logger.Trace("Windows CredentialHelper: {0}", credentialHelper);
	afterGitSetup.Start();
	}
	else
	{
	Logger.Warning("No Windows CredentialHeloper found: Setting to wincred");
	GitClient.SetConfig("credential.helper", "wincred", GitConfigSource.Global)
	.Then(() => { afterGitSetup.Start(); }).Start();
	}
	}).Start();
	});
	var afterPathDetermined = new ActionTask<NPath>(CancellationToken, (b, path) => {
	Logger.Trace("Setting Environment git path: {0}", path);
	Environment.GitExecutablePath = path;
	}).ThenInUI(() => {
	Environment.User.Initialize(GitClient);
	if (Environment.IsWindows)
	{
	windowsCredentialSetup.Start();
	}
	else
	{
	afterGitSetup.Start();
	}
	});
	var findExecTask = new FindExecTask("git", CancellationToken)
	.Finally((b, ex, path) => {
	if (b && path != null)
	{
	Logger.Trace("FindExecTask Success: {0}", path);
	new FuncTask<NPath>(CancellationToken, () => path)
	.Then(afterPathDetermined)
	.Start();
	}
	else
	{
	Logger.Warning("FindExecTask Failure");
	Logger.Error("Git not found");
	}
	});
	var applicationDataPath = Environment.GetSpecialFolder(System.Environment.SpecialFolder.LocalApplicationData).ToNPath();
	var installDetails = new GitInstallDetails(applicationDataPath, true);
	var gitInstaller = new GitInstaller(Environment, CancellationToken, installDetails);
	gitInstaller.SetupGitIfNeeded(new ActionTask<NPath>(CancellationToken, (b, path) => {
	Logger.Trace("GitInstaller Success: {0}", path);
	new FuncTask<NPath>(CancellationToken, () => path)
	.Then(afterPathDetermined)
	.Start();
	}), new ActionTask(CancellationToken, () => {
	Logger.Warning("GitInstaller Failure");
	findExecTask.Start();
	}) );
	}

In order to make this process asynchronous.
Several async tasks are created, upon their completion they choose which tasks to continue with.

Async Install flow

• DEFINE After git is setup
  • Restart Repository
  • Initialize UI
• DEFINE Windows Credential setup
  • Set windows credential helper
  • START "After git is setup"
• DEFINE After path is determined
  • If windows START "Windows Credential setup"
  • Otherwise START "After git is setup"
• DEFINE Locate system git
  • If successful START "After path is determined"
  • Else throw ERROR
• DEFINE Locate or install portable git
  • If successful START "After path is determined"
  • Else START "Locate system git"
• DEFINE Check settings for git path
  • If successful START "After path is determined"
  • Else START "Locate or install portable git"

START "Check settings for git path"

Git Installer

This process is now async and performs the following tasks:

• Check for the existence of our Portable Git folder
  • Check that the extracted directory exists
  • Use a file list MD5 to verify that all expected files are present
    • Using a file list MD5 because this would be run on every startup and a full MD5 takes a few seconds
    • It would also be overkill because a full MD5 is performed on the zip files output
  • Perform a full MD5 on Git LFS
• If Portable Git is not discovered to be intact
  • Check if it can use portable git based on OS (we don't ship portable git for mac currently, but for when we do)
  • Uses UnzipTask to unzip both zip files and perform a full MDS on the results
  • Creates a combined output and moves it to the target directory
  • Cleanup after itself

UI Changes

• Changes to UserSettingsView and InitProjectView to remain disabled until git is ready

[StanleyGoldman]

I realized I have one regression, which if you read my documentation you will catch.
I'm missing a check against settings to see if the person has chosen a git.

[StanleyGoldman]

Fixed

[drguthals]

This looks good!