Set the Delve port dynamically for remote debug

README.md

@@ -9,6 +9,7 @@ An extension for [nvim-dap][1] providing configurations for launching go debugge
 - Configuration to attach nvim-dap and Delve into a running process and start a debug session.
 - Configuration to start a debug session in the main function.
 - Configuration to run tests in a debug session.
+- Final Delve configuration is resolved when a debug session starts. This allows to use different addresses and ports for each project or launch configs in a project.
 
 ## Pre-reqs
 
@@ -67,7 +68,9 @@ lua require('dap-go').setup {
     initialize_timeout_sec = 20,
     -- a string that defines the port to start delve debugger.
     -- default to string "${port}" which instructs nvim-dap
-    -- to start the process in a random available port
+    -- to start the process in a random available port.
+    -- if you set a port in your debug configuration, its value will be
+    -- assigned dynamically.
     port = "${port}",
     -- additional args to pass to dlv
     args = {},
@@ -196,6 +199,39 @@ dlv debug -l 127.0.0.1:38697 --headless ./main.go -- subcommand --myflag=xyz
 nmap <silent> <leader>td :lua require('dap-go').debug_test()<CR>
 ```
 
+## VSCode launch config
+
+Defining the Go debug configurations for all your projects inside your Neovim configuration can be cumbersome and quite strict.
+For more flexibility, `nvim-dap` supports the use of the VSCode launch configurations.
+
+That allows for example to set the Delve port dynamically when you run a debug session. If you create this file in your project (`[root_project]/.vscode/launch.json`):
+
+```json
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Remote debug API server",
+            "type": "go",
+            "request": "attach",
+            "mode": "remote",
+            "port": 4444,
+            "host": "127.0.0.1",
+            "substitutePath": [
+                {
+                    "from": "${workspaceFolder}", "to": "/usr/src/app"
+                }
+            ]
+        }
+    ]
+}
+```
+
+A debug session `Remote debug API server` will appear in the choices, and the Delve port will be dynamically set to `4444`.
+The current version of nvim-dap always loads the file if it exists.
+
+Please see `:h dap-launch.json` for more information.
+
 ## Acknowledgement
 
 Thanks to the [nvim-dap-python][6] for the inspiration.

doc/nvim-dap-go.txt

@@ -17,7 +17,8 @@ CONTENTS                                                  *dap-go-toc*
     5. Debugging With Command-Line Arguments . |dap-go-debug-cli-args|
     6. Debugging With Build Flags ............ |dap-go-debug-cli-args|
     7. Debugging With dlv in Headless Mode ... |dap-go-debug-headless|
-    8. Mappings .............................. |dap-go-mappings|
+    8. VSCode launch config .................. |dap-go-vscode-launch|
+    9. Mappings .............................. |dap-go-mappings|
 
 ========================================================================
 FEATURES                                             *dap-go-features*
@@ -36,6 +37,10 @@ FEATURES                                             *dap-go-features*
 
 - Configuration to run tests in a debug session.
 
+- Final Delve configuration is resolved when a debug session starts.
+  This allows to use different addresses and ports for each project or
+  launch configs in a project.
+
 This plugin makes usage of treesitter to find the nearest test to
 debug. Make sure you have the Go treesitter parser installed. If using
 |nvim-treesitter| plugin you can install with `:TSInstall go`.
@@ -80,7 +85,9 @@ The example bellow shows all the possible configurations:
         initialize_timeout_sec = 20,
         -- a string that defines the port to start delve debugger.
         -- default to string "${port}" which instructs nvim-dap
-        -- to start the process in a random available port
+        -- to start the process in a random available port.
+        -- if you set a port in your debug configuration, its value will be
+        -- assigned dynamically.
         port = "${port}",
         -- additional args to pass to dlv
         args = {},
@@ -207,6 +214,38 @@ Debugging With dlv in Headless Mode           *dap-go-debug-headless*
     3. Call `:lua require('dap').continue()` to start debugging.
     4. Select the new registered option `Attach remote`.
 
+-----------------------------------------------------------------------
+VSCode launch config                           *dap-go-vscode-launch
+
+    1. Create in your Go project a VSCode launch config file (by
+    default its path must be `.vscode/launch.json` relative to your
+    project's root directory):
+>json
+    {
+        "version": "0.2.0",
+        "configurations": [
+            {
+                "name": "Remote debug API server",
+                "type": "go",
+                "request": "attach",
+                "mode": "remote",
+                "port": 4444,
+                "host": "127.0.0.1",
+                "substitutePath": [
+                    {
+                        "from": "${workspaceFolder}", "to": "/usr/src/app"
+                    }
+                ]
+            }
+        ]
+    }
+<
+
+    2. A debug session `Remote debug API server` will appear in the choices,
+    and the Delve port will be dynamically set to `4444`.
+
+Please see `:h dap-launch.json` for more information.
+
 ========================================================================
 MAPPINGS                                             *dap-go-mappings*
 
@@ -220,5 +259,4 @@ mappings. You can do this by adding the lines bellow to your
     vim.keymap.set("n", "<leader>dt", dapgo.debug_test)
     vim.keymap.set("n", "<leader>dl", dapgo.debug_last_test)
 <
-
 vim:tw=78:et:ft=help:norl:

lua/dap-go.lua

@@ -66,7 +66,7 @@ local function setup_delve_adapter(dap, config)
   local args = { "dap", "-l", "127.0.0.1:" .. config.delve.port }
   vim.list_extend(args, config.delve.args)
 
-  dap.adapters.go = {
+  local delve_config = {
     type = "server",
     port = config.delve.port,
     executable = {
@@ -79,10 +79,28 @@ local function setup_delve_adapter(dap, config)
       initialize_timeout_sec = config.delve.initialize_timeout_sec,
     },
   }
+
+  dap.adapters.go = function(callback, client_config)
+    if client_config.port == nil then
+      callback(delve_config)
+      return
+    end
+
+    local host = client_config.host
+    if host == nil then
+      host = "127.0.0.1"
+    end
+
+    local listener_addr = host .. ":" .. client_config.port
+    delve_config.port = client_config.port
+    delve_config.executable.args = { "dap", "-l", listener_addr }
+
+    callback(delve_config)
+  end
 end
 
 local function setup_go_configuration(dap, configs)
-  dap.configurations.go = {
+  local common_debug_configs = {
     {
       type = "go",
       name = "Debug",
@@ -139,6 +157,14 @@ local function setup_go_configuration(dap, configs)
     },
   }
 
+  if dap.configurations.go == nil then
+    dap.configurations.go = {}
+  end
+
+  for _, config in ipairs(common_debug_configs) do
+    table.insert(dap.configurations.go, config)
+  end
+
   if configs == nil or configs.dap_configurations == nil then
     return
   end