add :PylspInstall command for managing 3rd party pylsp plugins (#318)

2 files changed, 37 insertions, 0 deletions

diff --git a/lua/nvim-lsp-installer/servers/pylsp/README.md b/lua/nvim-lsp-installer/servers/pylsp/README.md
new file mode 100644
index 00000000..ce756de3
--- /dev/null
+++ b/lua/nvim-lsp-installer/servers/pylsp/README.md
@@ -0,0 +1,9 @@
+# Pylsp
+
+## Installing pylsp plugins
+Pylsp has [third party plugins](https://github.com/python-lsp/python-lsp-server#3rd-party-plugins) which are not installed by default.
+
+In order for these plugins to work with the `pylsp` server managed by this plugin, they need to be installed in the same [virtual environment](https://docs.python.org/3/library/venv.html) as `pylsp`. For these reasons, there's a convenient `:PylspInstall <packages>` command that does this for you, for example:
+```vim
+:PylspInstall pyls-flake8 pylsp-mypy pyls-isort
+```
diff --git a/lua/nvim-lsp-installer/servers/pylsp/init.lua b/lua/nvim-lsp-installer/servers/pylsp/init.lua
index e3da8e21..9905dd68 100644
--- a/lua/nvim-lsp-installer/servers/pylsp/init.lua
+++ b/lua/nvim-lsp-installer/servers/pylsp/init.lua
@@ -1,5 +1,7 @@
 local server = require "nvim-lsp-installer.server"
 local pip3 = require "nvim-lsp-installer.installers.pip3"
+local process = require "nvim-lsp-installer.process"
+local notify = require "nvim-lsp-installer.notify"
 
 return function(name, root_dir)
     return server.Server:new {
@@ -10,6 +12,32 @@ return function(name, root_dir)
         installer = pip3.packages { "python-lsp-server[all]" },
         default_options = {
             cmd = { pip3.executable(root_dir, "pylsp") },
+            commands = {
+                PylspInstall = {
+                    function(...)
+                        -- `nargs+` requires at least one argument -> no empty table
+                        local plugins = { ... }
+                        local plugins_str = table.concat(plugins, ", ")
+                        notify(("Installing %q..."):format(plugins_str))
+                        process.spawn(
+                            pip3.executable(root_dir, "pip"),
+                            {
+                                args = vim.list_extend({ "install", "-U", "--disable-pip-version-check" }, plugins),
+                                stdio_sink = process.simple_sink(),
+                            },
+                            vim.schedule_wrap(function(success)
+                                if success then
+                                    notify(("Successfully installed %q"):format(plugins_str))
+                                else
+                                    notify("Failed to install requested plugins.", vim.log.levels.ERROR)
+                                end
+                            end)
+                        )
+                    end,
+                    description = "Installs the provided packages in the same venv as pylsp.",
+                    ["nargs=+"] = true,
+                },
+            },
         },
     }
 end