RepositoryManager.cs

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using System;
using System.Threading;
using System.Threading.Tasks;
 
using LibGit2Sharp;
 
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
 
using Tgstation.Server.Api.Models;
using Tgstation.Server.Host.Components.Events;
using Tgstation.Server.Host.Configuration;
using Tgstation.Server.Host.Extensions;
using Tgstation.Server.Host.IO;
using Tgstation.Server.Host.Jobs;
using Tgstation.Server.Host.Utils;
 
namespace Tgstation.Server.Host.Components.Repository
{
    sealed class RepositoryManager : IRepositoryManager
    {
        public bool InUse => semaphore.CurrentCount == 0;
 
        public bool CloneInProgress { get; private set; }
 
        readonly ILibGit2RepositoryFactory repositoryFactory;
 
        readonly ILibGit2Commands commands;
 
        readonly IIOManager ioManager;
 
        readonly IEventConsumer eventConsumer;
 
        readonly IPostWriteHandler postWriteHandler;
 
        readonly IGitRemoteFeaturesFactory gitRemoteFeaturesFactory;
 
        readonly IOptionsMonitor<GeneralConfiguration> generalConfigurationOptions;
 
        readonly ILogger<Repository> repositoryLogger;
 
        readonly ILogger<RepositoryManager> logger;
 
        readonly SemaphoreSlim semaphore;
 
        public RepositoryManager(
            ILibGit2RepositoryFactory repositoryFactory,
            ILibGit2Commands commands,
            IIOManager ioManager,
            IEventConsumer eventConsumer,
            IPostWriteHandler postWriteHandler,
            IGitRemoteFeaturesFactory gitRemoteFeaturesFactory,
            IOptionsMonitor<GeneralConfiguration> generalConfigurationOptions,
            ILogger<Repository> repositoryLogger,
            ILogger<RepositoryManager> logger)
        {
            this.repositoryFactory = repositoryFactory ?? throw new ArgumentNullException(nameof(repositoryFactory));
            this.commands = commands ?? throw new ArgumentNullException(nameof(commands));
            this.ioManager = ioManager ?? throw new ArgumentNullException(nameof(ioManager));
            this.eventConsumer = eventConsumer ?? throw new ArgumentNullException(nameof(eventConsumer));
            this.postWriteHandler = postWriteHandler ?? throw new ArgumentNullException(nameof(postWriteHandler));
            this.gitRemoteFeaturesFactory = gitRemoteFeaturesFactory ?? throw new ArgumentNullException(nameof(gitRemoteFeaturesFactory));
            this.repositoryLogger = repositoryLogger ?? throw new ArgumentNullException(nameof(repositoryLogger));
            this.generalConfigurationOptions = generalConfigurationOptions ?? throw new ArgumentNullException(nameof(generalConfigurationOptions));
            this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
            semaphore = new SemaphoreSlim(1);
        }
 
        public void Dispose()
        {
            logger.LogTrace("Disposing...");
            semaphore.Dispose();
        }
 
        public async ValueTask<IRepository?> CloneRepository(
            Uri url,
            string? initialBranch,
            string? username,
            string? password,
            JobProgressReporter progressReporter,
            bool recurseSubmodules,
            CancellationToken cancellationToken)
        {
            ArgumentNullException.ThrowIfNull(url);
            lock (semaphore)
            {
                if (CloneInProgress)
                    throw new JobException(ErrorCode.RepoCloning);
                CloneInProgress = true;
            }
 
            var repositoryPath = ioManager.ResolvePath();
            logger.LogInformation("Begin clone {url} to {path} (Branch: {initialBranch})", url, repositoryPath, initialBranch);
 
            try
            {
                using (await SemaphoreSlimContext.Lock(semaphore, cancellationToken))
                {
                    logger.LogTrace("Semaphore acquired for clone");
                    if (!await ioManager.DirectoryExists(repositoryPath, cancellationToken))
                        try
                        {
                            using var cloneProgressReporter = progressReporter.CreateSection(null, 0.75f);
                            using var checkoutProgressReporter = progressReporter.CreateSection(null, 0.25f);
                            var cloneOptions = new CloneOptions
                            {
                                RecurseSubmodules = recurseSubmodules,
                                OnCheckoutProgress = (path, completed, remaining) =>
                                {
                                    if (checkoutProgressReporter == null)
                                        return;
 
                                    var percentage = (double)completed / remaining;
                                    checkoutProgressReporter.ReportProgress(percentage);
                                },
                                BranchName = initialBranch,
                            };
 
                            cloneOptions.FetchOptions.Hydrate(
                                logger,
                                cloneProgressReporter,
                                await repositoryFactory.GenerateCredentialsHandler(
                                    gitRemoteFeaturesFactory.CreateGitRemoteFeatures(url),
                                    username,
                                    password,
                                    cancellationToken),
                                cancellationToken);
 
                            await repositoryFactory.Clone(
                                url,
                                cloneOptions,
                                repositoryPath,
                                cancellationToken);
                        }
                        catch
                        {
                            try
                            {
                                logger.LogTrace("Deleting partially cloned repository...");
 
                                // DCT: Cancellation token is for job, operation must run regardless
                                await ioManager.DeleteDirectory(repositoryPath, CancellationToken.None);
                            }
                            catch (Exception innerException)
                            {
                                logger.LogError(innerException, "Error deleting partially cloned repository!");
                            }
 
                            throw;
                        }
                    else
                    {
                        logger.LogDebug("Repository exists, clone aborted!");
                        return null;
                    }
                }
            }
            finally
            {
                logger.LogTrace("Semaphore released after clone");
                CloneInProgress = false;
            }
 
            logger.LogInformation("Clone complete!");
            return await LoadRepository(cancellationToken);
        }
 
        public async ValueTask<IRepository?> LoadRepository(CancellationToken cancellationToken)
        {
            logger.LogTrace("Begin LoadRepository...");
            lock (semaphore)
                if (CloneInProgress)
                    throw new JobException(ErrorCode.RepoCloning);
 
            try
            {
                await semaphore.WaitAsync(cancellationToken);
                try
                {
                    logger.LogTrace("Semaphore acquired for load");
                    var libGit2Repo = await repositoryFactory.CreateFromPath(ioManager.ResolvePath(), cancellationToken);
 
                    return new Repository(
                        libGit2Repo,
                        commands,
                        ioManager,
                        eventConsumer,
                        repositoryFactory,
                        postWriteHandler,
                        gitRemoteFeaturesFactory,
                        repositoryFactory,
                        generalConfigurationOptions,
                        repositoryLogger,
                        () =>
                        {
                            logger.LogTrace("Releasing semaphore due to Repository disposal...");
                            semaphore.Release();
                        });
                }
                catch
                {
                    logger.LogTrace("Releasing semaphore as load failed");
                    semaphore.Release();
                    throw;
                }
            }
            catch (RepositoryNotFoundException e)
            {
                logger.LogTrace(e, "Repository not found!");
                return null;
            }
        }
 
        public async ValueTask DeleteRepository(CancellationToken cancellationToken)
        {
            logger.LogInformation("Deleting repository...");
            try
            {
                using (await SemaphoreSlimContext.Lock(semaphore, cancellationToken))
                {
                    logger.LogTrace("Semaphore acquired, deleting Repository directory...");
                    await ioManager.DeleteDirectory(ioManager.ResolvePath(), cancellationToken);
                }
            }
            finally
            {
                logger.LogTrace("Semaphore released after delete attempt");
            }
        }
    }
}