Hi Kou, thanks for your insight > If we have many development resources for the C# bindings, > it may be better that we implement the C++ bindings directly > like PyArrow does. If we doesn't, it may be better that we > use Arrow GLib to combine development resources with > GLib/Ruby developers like me.
I think it's fair to say there isn't a lot of developer time dedicated to the C# library and bindings, but I can see there being demand for bindings to the full dataset and compute APIs at least, so from that perspective it sounds like using the GLib libraries would make sense. > We may want to publish a NuGet package that includes Arrow > GLib libraries like ParquetSharp includes > ParquetSharpNative.* that are liked to Arrow/Parquet C++ > statically. Good point, that would definitely help simplify things for end users. > We may want to create a C# library in addition of auto > generated codes based on GObject Introspection. It's an > approach used by Ruby. The auto generated codes may be > difficult to use from C#. Right, yes this is similar to what I meant by not publicly exposing the GLib.GObject based classes, although we could do something closer to this where we make the GObject classes public but in a separate namespace, and provide a cleaner API built on top of the generated code but allow users to access the lower level GObject API if needed. > > I was worried about whether it's possible to use GObject to implement > > bindings for some of the more complex parts of the Dataset API, like > > providing a .NET implementation of a KmsClientFactory, which would be > > required for reading encrypted Parquet data. > > We can use GObject for the case as you did. I can open a PR > for it or I can review your implementation. (If you open a > PR of your work.) The code I have is more like a prototype of a simplified version of the KMS API, so it's not useful as is, but I'll look into expanding this to implement the full API and make a PR. Cheers, Adam On Tue, 7 May 2024 at 20:11, Sutou Kouhei <k...@clear-code.com> wrote: > > Hi, > > I'm the author of Arrow GLib. > > I agree with Pros/Cons you summarized. > > If we have many development resources for the C# bindings, > it may be better that we implement the C++ bindings directly > like PyArrow does. If we doesn't, it may be better that we > use Arrow GLib to combine development resources with > GLib/Ruby developers like me. > > If we don't have many development resources for the C# > bindings but we don't need many bindings, it may be better > that we implement the C++ bindings directly. > > > * There's no need to distribute a native binary with NuGet packages, > > and NuGet packages aren't bloated by builds for architectures that > > aren't used > > > * Users need to separately install the Arrow GLib libraries in order > > to use some Arrow NuGet packages, and this might complicate build and > > deployment processes compared to just adding a NuGet package reference > > to a project > > We may want to publish a NuGet package that includes Arrow > GLib libraries like ParquetSharp includes > ParquetSharpNative.* that are liked to Arrow/Parquet C++ > statically. > > > We may want to create a C# library in addition of auto > generated codes based on GObject Introspection. It's an > approach used by Ruby. The auto generated codes may be > difficult to use from C#. > > For example, both of the following Ruby codes read a table: > > # With a Ruby library > table = Arrow::Table.load("data.arrow") > > # Without a Ruby library (Use only auto generated API) > input = Arrow::memoryMappedInputStream.new("data.arrow") > reader = Arrow::RecordBatchFileReader.new(input) > table = reader.read_all > > > > I was worried about whether it's possible to use GObject to implement > > bindings for some of the more complex parts of the Dataset API, like > > providing a .NET implementation of a KmsClientFactory, which would be > > required for reading encrypted Parquet data. > > We can use GObject for the case as you did. I can open a PR > for it or I can review your implementation. (If you open a > PR of your work.) > > > > Thanks, > -- > kou > > In <cagzxcpddxnkez7jyokrfgygijlnqow7ikch1+5fmy1c_hzi...@mail.gmail.com> > "[DISCUSS][C#][GLib] Formalize use of the GLib libraries for native library > bindings" on Tue, 7 May 2024 12:32:40 +1200, > Adam Reeve <adre...@gmail.com> wrote: > > > Hi everyone, > > > > The .NET/C# Apache Arrow library currently only contains managed code, > > but the addition of the C Data Interface implementation opens up the > > ability to easily add bindings to the C++ Arrow library to add more > > capabilities. There is currently a draft PR open to add bindings to > > the Acero library for example [1], and I'm interested in adding .NET > > bindings to the dataset library. > > > > The Acero bindings PR uses the Arrow GLib library, but I couldn't find > > any official guidance on whether this is the recommended approach for > > adding new native library bindings. As far as I can tell the GLib > > libraries are currently only used for the Ruby Arrow library, and can > > be used via GObject introspection by other languages like Lua. So I'd > > like to start a discussion to see if there's consensus on whether > > using the GLib libraries should be the standard way to add new native > > library bindings for .NET. Standardising on one way of wrapping the > > C++ libraries in .NET would help keep things simpler for both users > > and developers. > > > > For context, I'm a member of the open-source team at G-Research and a > > maintainer of ParquetSharp, a .NET library that wraps the Arrow C++ > > Parquet library. In ParquetSharp, we build our own native library with > > a C ABI that uses the C++ Arrow library from vcpkg internally, and > > bundle pre-built native libraries inside the ParquetSharp Nuget > > package for each OS and architecture combination supported. > > > > My thoughts on the advantages and disadvantages of using GLib over a > > custom native wrapper library are: > > Pros > > * We can use the existing GLib Arrow libraries rather than having to > > write custom C wrappers, and any improvements made there to support > > .NET can also benefit users of other languages, and vice versa > > (although this would only be Ruby and .NET initially, and anyone using > > the library directly via GObject introspection) > > * We can take advantage the tooling built around GLib/GObject to avoid > > needing to implement a lot of boilerplate binding code manually. For > > example, we could use the GapiCodegen tool from GtkSharp [2] to help > > generate binding code > > * There's no need to distribute a native binary with NuGet packages, > > and NuGet packages aren't bloated by builds for architectures that > > aren't used > > Cons > > * Users need to separately install the Arrow GLib libraries in order > > to use some Arrow NuGet packages, and this might complicate build and > > deployment processes compared to just adding a NuGet package reference > > to a project > > * GLib code can be a lot more complicated than plain C binding code > > that is only going to be consumed by .NET > > * Automatically generating .NET bindings for GObject libraries is not > > as well supported as for some other languages/runtimes > > * As far as I can tell it's expected that most .NET GLib library > > bindings live inside one of the many forks of GtkSharp so all of the > > tooling is internal to these repositories rather than being > > distributed as standalone tools designed to be used by other projects > > * You can manually write code to use a GLib library, as in the > > Acero C# PR, but for more complex APIs I think it would make sense to > > take advantage of the automated tooling available > > > > I was worried about whether it's possible to use GObject to implement > > bindings for some of the more complex parts of the Dataset API, like > > providing a .NET implementation of a KmsClientFactory, which would be > > required for reading encrypted Parquet data. I recently added bindings > > for this to ParquetSharp [3], so thought it would be a good test case > > to try to implement something similar with GObject. Following the GTK > > interface docs [4] and GtkSharp interface binding docs [5], and using > > the GapiCodegen library, I was able to implement something like a > > KmsClientFactory in C# and use it from GObject code in a C library, so > > it doesn't look like using GObject would be too limiting. It did take > > me a while to get this working though and I had a few missteps along > > the way, like trying to get gapi-parser working before giving up and > > writing an API XML file manually. > > > > I do think that if we use GapiCodegen we might want to avoid publicly > > exposing classes that inherit from GLib.Object in order to keep the > > API simple and provide more flexibility to change things in backwards > > compatible ways as the library evolves. > > > > Does anyone have any opinions or thoughts on this? > > > > Thanks, > > Adam > > > > [1] https://github.com/apache/arrow/pull/37544 > > [2] https://github.com/GtkSharp/GtkSharp > > [3] https://github.com/G-Research/ParquetSharp/pull/426 > > [4] > > https://docs.gtk.org/gobject/tutorial.html#how-to-define-and-implement-interfaces > > [5] https://www.mono-project.com/docs/gui/gtksharp/implementing-ginterfaces/