GitObjectDb.SystemTextJson 0.2.2-alpha

GitObjectDb simplifies the configuration management versioning by backing it in Git.

Name	Badge
GitObjectDb
GitObjectDb.Api
GitObjectDb.OData
GitObjectDb.GraphQL

Overview

GitObjectDb is designed to simplify the configuration management versioning. It does so by removing the need for hand-coding the commands needed to interact with Git.

The Git repository is used as a pure database as the files containing the serialized copy of the objects are never fetched in the filesystem. GitObjectDb only uses the blob storage provided by Git.

Here's a simple example:

1. Define your own repository data model:

   [GitFolder("Applications")]
   public record Application : Node
   {
       public string Name { get; set; }
   
       public string Description { get; set; }
   }
   [GitFolder("Pages")]
   public record Table : Node
   {
       public string Name { get; set; }
   
       public string Description { get; set; }
   }
   

2. Manipulate objects as follows:

    var existingApplication = connection.Lookup<Application>("applications", new UniqueId(id));
    var newTable = new Table { ... };
    connection
        .Update(c => c.CreateOrUpdate(newTable, parent: existingApplication))
    	.Commit("Added new table.", author, committer);
   

Features

Structured & unstructured data storage

var node = new SomeNode
{
    SomeProperty = "Value stored as json",
    EmbeddedResource = "Value stored as raw text in same Git blob",
}:

... gets stored in Git as follows:

{
  "Type": "Sample.SomeNode, Sample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null",
  "Node": {
    "$id": "SomeNodes/zerzrzrz.json",
    "id": "zerzrzrz",
    "someProperty": "Value stored as json"
  }
}
/*
Value stored as raw text in same Git blob
*/

You can also store resources as separate files:

new Resource(node, "Some/Folder", "File.txt", new Resource.Data("Value stored in a separate file in <node path>/Resources/Some/Folder/File.txt"));

Branching

connection
    .Update(c => c.CreateOrUpdate(table with { Description = newDescription }))
    .Commit("Some message", signature, signature);
connection.Checkout("newBranch", "HEAD~1");
connection
    .Update(c => c.CreateOrUpdate(table with { Name = newName }))
    .Commit("Another message", signature, signature);

History

var commits = sut.Commits
    .QueryBy(new CommitFilter
    {
        IncludeReachableFrom = sut.Head.Tip,
        SortBy = CommitSortStrategies.Reverse | CommitSortStrategies.Topological,
    })
    .Take(5)

Compare commits

var comparison = connection.Compare("HEAD~1", repository.Head.Tip.Sha);
var nodeChanges = comparison.Modified.OfType<Change.NodeChange>();

Node references

Node references allows linking existing nodes in a repository:

public record Order : Node
{
    public Client Client { get; set; }
    // ...
}
public record Client : Node
{
    // ...
}
// Nodes get loaded with their references (using a shared )
var cache = new Dictionary<DataPath, ITreeItem>();
var order = connection.GetNodes<Order>(referenceCache: cache).First();
Console.WriteLine(order.Client.Id);

Merge, Rebase, Cherry-pick

// main:      A---B    A---B
//             \    ->  \   \
// newBranch:   C        C---x

connection
    .Update(c => c.CreateOrUpdate(table with { Description = newDescription }))
    .Commit("B", signature, signature);
connection.Checkout("newBranch", "HEAD~1");
connection
    .Update(c => c.CreateOrUpdate(table with { Name = newName }))
    .Commit("C", signature, signature);

sut.Merge(upstreamCommittish: "main");

Node versioning management

Imagine a scenario where you define in your code a first type:

[GitFolder(FolderName = "Items", UseNodeFolders = false)]
[IsDeprecatedNodeType(typeof(SomeNodeV2))]
private record SomeNodeV1 : Node
{
    public int Flags { get; set; }
}

[GitFolder(FolderName = "Items", UseNodeFolders = false)]
private record SomeNodeV2 : Node
{
    public BindingFlags TypedFlags { get; set; }
}

You then want to introduce a new change so that the Flags property contains more meaningful information, relying on enums:

[GitFolder(FolderName = "Items", UseNodeFolders = false)]
private record SomeNodeV2 : Node
{
    public BindingFlags TypedFlags { get; set; }
}

All you need to do is to #1 add the [IsDeprecatedNodeType(typeof(SomeNodeV2))] attribute. This will instruct the deserializer to convert nodes to new version, using a converter. #2 converter needs to be provided in the model. You can use AutoMapper or other tools at your convenience.

[GitFolder(FolderName = "Items", UseNodeFolders = false)]
[IsDeprecatedNodeType(typeof(SomeNodeV2))]
private record SomeNodeV1 : Node
{
    // ...
}
var model = new ConventionBaseModelBuilder()
    .RegisterType<SomeNodeV1>()
    .RegisterType<SomeNodeV2>()
    .AddDeprecatedNodeUpdater(UpdateDeprecatedNode)
    .Build();
Node UpdateDeprecatedNode(Node old, Type targetType)
{
    var nodeV1 = (SomeNodeV1)old;
    return new SomeNodeV2
    {
        Id = old.Id,
        TypedFlags = (BindingFlags)nodeV1.Flags,
    };
}

Documentation

See Documentation.

Prerequisites

• .NET Standard 2.0 or 2.1

Online resources

• LibGit2Sharp (Requires NuGet 2.7+)

Quick contributing guide

• Fork and clone locally
• Create a topic specific branch. Add some nice feature. Do not forget the tests 😉
• Send a Pull Request to spread the fun!

License

The MIT license (Refer to the LICENSE file).