Integrate with the Buildx Dockerfile debugger (#27)

Buildx implements DAP to allow users to debug Dockerfile builds.

<img width="1666" height="842" alt="image"
src="https://github.com/user-attachments/assets/9cda3d58-6d04-48b4-a204-9009a6264908"
/>

<img width="3106" height="1319" alt="image"
src="https://github.com/user-attachments/assets/88092f52-d251-4090-acca-0792f01fbe58"
/>

---------

Signed-off-by: Remy Suen <remy.suen@docker.com>

Author: rcjsuen

Cargo.lock

@@ -8,4 +8,6 @@ publish = false
 crate-type = ["cdylib"]
 
 [dependencies]
+serde = {version = "1.0", features = ["derive"]}
+serde_json = "1.0"
 zed_extension_api = "0.7.0"

Cargo.toml

@@ -10,7 +10,34 @@ To support matching filenames other than `Dockerfile` you can add [`file_types`]
 ```json
 {
   "file_types": {
-    "Dockerfile": [ "Dockerfile.*" ]
+    "Dockerfile": ["Dockerfile.*"]
   }
 }
 ```
+
+## Debugging
+
+The extension supports debugging Dockerfile builds with [Buildx](https://github.com/docker/buildx). The minimal required version of Buildx is v0.28.0. To get Buildx, we recommend installing or updating [Docker Desktop](https://docs.docker.com/install/). You may alternatively install Buildx manually by following the instructions [here](https://github.com/docker/buildx?tab=readme-ov-file#manual-download).
+
+You can validate your Buildx installation by running `BUILDX_EXPERIMENTAL=1 docker buildx dap`.
+
+You can create a debug configuration by modifying your project's `.zed/debug.json`.
+
+```json
+{
+  "label": "Docker: Build", // required, configurable
+  "adapter": "buildx-dockerfile", // required, must not be modified
+  "request": "launch", // required, must not be modified
+  "contextPath": "/home/username/worktree", // optional, defaults to ${ZED_WORKTREE_ROOT}
+  "dockerfile": "/home/username/worktree/Dockerfile", // optional, defaults to ${ZED_WORKTREE_ROOT}/Dockerfile
+  "target": "test", // optional, should be a build stage in the Dockerfile
+  "stopOnEntry": true, // if the debugger should suspend on the first line, defaults to false
+  "args": [
+    // additional arguments for the build command
+    "--build-arg",
+    "NODE_ENV=development"
+  ]
+}
+```
+
+While a build has been suspended, you can evaluate `exec` to open a shell into the Docker image that has been built up to that point in time.

README.md

@@ -0,0 +1,38 @@
+{
+  "type": "object",
+  "required": ["request"],
+  "properties": {
+    "dockerfile": {
+      "type": "string",
+      "description": "The absolute path to the Dockerfile to debug",
+      "default": "${ZED_WORKTREE_ROOT}/Dockerfile"
+    },
+    "contextPath": {
+      "type": "string",
+      "description": "Path to the context of the Docker build",
+      "default": "${ZED_WORKTREE_ROOT}"
+    },
+    "request": {
+      "type": "string",
+      "description": "The type of debug session to run, must be launch",
+      "enum": ["launch"],
+      "default": "launch"
+    },
+    "target": {
+      "type": "string",
+      "description": "The build stage target to build"
+    },
+    "stopOnEntry": {
+      "type": "boolean",
+      "description": "Whether the build should stop in the beginning"
+    },
+    "args": {
+      "type": "array",
+      "description": "Command line arguments to pass to the build command",
+      "items": {
+        "type": "string"
+      },
+      "default": []
+    }
+  }
+}

debug_adapter_schemas/buildx-dockerfile.json

@@ -13,3 +13,6 @@ language = "Dockerfile"
 [grammars.dockerfile]
 repository = "https://github.com/camdencheek/tree-sitter-dockerfile"
 commit = "868e44ce378deb68aac902a9db68ff82d2299dd0"
+
+[debug_adapters.buildx-dockerfile]
+schema_path = "./debug_adapter_schemas/buildx-dockerfile.json"