[API Proposal]: Expose dotnet info by introducing a new hostfxr API

[Markliniubility]

Background and motivation

dotnet SDK intends to implement a new command dotnet info to replace the original dotnet --info. The detail is specified in dotnet/sdk#33697.

However, to implement this new command, we need to have some information exposed in the corehost, which are:

• Host,
• .NET SDKs installed,
• .NET runtimes installed,
• Other architectures found,
• Environment Variables, and
• global.json file

We may make modification to this file to introduce the new API

runtime/src/native/corehost/hostfxr.h

Lines 311 to 323 in c28bec4

	struct hostfxr_dotnet_environment_info
	{
	size_t size;
	const char_t* hostfxr_version;
	const char_t* hostfxr_commit_hash;
	size_t sdk_count;
	const struct hostfxr_dotnet_environment_sdk_info* sdks;
	size_t framework_count;
	const struct hostfxr_dotnet_environment_framework_info* frameworks;
	};

API Proposal

SHARED_API int32_t HOSTFXR_CALLTYPE hostfxr_get_dotnet_host_info(
    const pal::char_t* dotnet_root,
    void* reserved,
    hostfxr_get_dotnet_host_info_result_fn result,
    void* result_context)
{}

API Usage

        [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Auto)]
        internal delegate void hostfxr_get_dotnet_environment_info_result_fn(
            IntPtr info,
            IntPtr result_context);

        [DllImport(Constants.HostFxr, CharSet = CharSet.Auto, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
        internal static extern int hostfxr_get_dotnet_host_info(
            .....);

Alternative Designs

No response

Risks

it would require some versioning magic but that doable (the host has to work against any SDK, so it would have to know to do the old thing for the old SDK and the new thing for the new SDK and unfortunately this can't be done through an API since the host literally runs the SDK as an app). ---- mentioned by @vitek-karas

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Issue Details

---

Background and motivation

dotnet SDK intends to implement a new command dotnet info to replace the original dotnet --info. The detail is specified in dotnet/sdk#33697.

However, to implement this new command, we need to have some information exposed in the corehost, which are:

• Host,
• .NET SDKs installed,
• .NET runtimes installed,
• Other architectures found,
• Environment Variables, and
• global.json file

We may make modification to this file to introduce the new API

runtime/src/native/corehost/hostfxr.h

Lines 311 to 323 in c28bec4

	struct hostfxr_dotnet_environment_info
	{
	size_t size;
	const char_t* hostfxr_version;
	const char_t* hostfxr_commit_hash;
	size_t sdk_count;
	const struct hostfxr_dotnet_environment_sdk_info* sdks;
	size_t framework_count;
	const struct hostfxr_dotnet_environment_framework_info* frameworks;
	};

API Proposal

SHARED_API int32_t HOSTFXR_CALLTYPE hostfxr_get_dotnet_host_info(
    const pal::char_t* dotnet_root,
    void* reserved,
    hostfxr_get_dotnet_host_info_result_fn result,
    void* result_context)
{}

API Usage

        [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Auto)]
        internal delegate void hostfxr_get_dotnet_environment_info_result_fn(
            IntPtr info,
            IntPtr result_context);

        [DllImport(Constants.HostFxr, CharSet = CharSet.Auto, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
        internal static extern int hostfxr_get_dotnet_host_info(
            .....);

Alternative Designs

No response

Risks

it would require some versioning magic but that doable (the host has to work against any SDK, so it would have to know to do the old thing for the old SDK and the new thing for the new SDK and unfortunately this can't be done through an API since the host literally runs the SDK as an app). ---- mentioned by @vitek-karas

Author:	Markliniubility
Assignees:	-
Labels:	api-suggestion, area-Host
Milestone:	-

[jkotas]

However, to implement this new command, we need to have some information exposed in the corehost,

Can SDK gather most or all of this information in managed code on its own?

For example, it does not make sense for the host to return environment variables. The managed dotnet info command can read the environment just fine.

[Markliniubility]

However, to implement this new command, we need to have some information exposed in the corehost,

Can SDK gather most or all of this information in managed code on its own?

For example, it does not make sense for the host to return environment variables. The managed dotnet info command can read the environment just fine.

Unfortunately, it may be a bit difficult to gather the information within the sdk repo. The current dotnet --info obtain the information from corehost as well. Ref.

runtime/src/native/corehost/fxr/command_line.cpp

Line 283 in 9da5359

void command_line::print_muxer_info(const pal::string_t &dotnet_root, const pal::string_t &global_json_path, bool skip_sdk_info_output)

The corehost will print out the info when there is a command dotnet --info.

[Markliniubility]

Some earlier discussions for this API proposal: dotnet/sdk#36943