Send structured InitializationOptions to the server (#121)

* Send structured `InitializationOptions` to the server

In particular, this lets us respect `air.logLevel` and `air.dependencyLogLevels` on server startup

User and workspace level settings are not used yet but are included for completeness

* Only send over `logLevel` and `dependencyLogLevels` as flat initialization options

* Remove unused cfg-attr

* Simplify `InitializationOptions` creation

* No need for `async`, and don't use interfacing naming

.vscode/settings.json

@@ -4,6 +4,10 @@
         "editor.formatOnSaveMode": "file",
         "editor.defaultFormatter": "rust-lang.rust-analyzer"
     },
+    "[typescript]": {
+        "editor.formatOnSave": true,
+        "editor.defaultFormatter": "esbenp.prettier-vscode"
+    },
     "rust-analyzer.check.command": "clippy",
     "rust-analyzer.imports.prefix": "crate",
     "rust-analyzer.imports.granularity.group": "item",

crates/lsp/src/handlers_state.rs

@@ -36,6 +36,7 @@ use crate::documents::Document;
 use crate::logging;
 use crate::logging::LogMessageSender;
 use crate::main_loop::LspState;
+use crate::settings::InitializationOptions;
 use crate::state::workspace_uris;
 use crate::state::WorldState;
 
@@ -65,9 +66,13 @@ pub(crate) fn initialize(
     state: &mut WorldState,
     log_tx: LogMessageSender,
 ) -> anyhow::Result<InitializeResult> {
-    // TODO: Get user specified options from `params.initialization_options`
-    let log_level = None;
-    let dependency_log_levels = None;
+    let InitializationOptions {
+        log_level,
+        dependency_log_levels,
+    } = params.initialization_options.map_or_else(
+        InitializationOptions::default,
+        InitializationOptions::from_value,
+    );
 
     logging::init_logging(
         log_tx,

crates/lsp/src/lib.rs

@@ -15,6 +15,7 @@ pub mod handlers_state;
 pub mod logging;
 pub mod main_loop;
 pub mod rust_analyzer;
+pub mod settings;
 pub mod state;
 pub mod to_proto;
 pub mod tower_lsp;

crates/lsp/src/main_loop.rs

@@ -145,7 +145,7 @@ pub(crate) struct GlobalState {
     log_tx: Option<LogMessageSender>,
 }
 
-/// Unlike `WorldState`, `ParserState` cannot be cloned and is only accessed by
+/// Unlike `WorldState`, `LspState` cannot be cloned and is only accessed by
 /// exclusive handlers.
 pub(crate) struct LspState {
     /// The negociated encoding for document positions. Note that documents are

crates/lsp/src/settings.rs

@@ -0,0 +1,24 @@
+use serde::Deserialize;
+use serde_json::Value;
+
+/// This is the exact schema for initialization options sent in by the client
+/// during initialization. Remember that initialization options are ones that are
+/// strictly required at startup time, and most configuration options should really be
+/// "pulled" dynamically by the server after startup and whenever we receive a
+/// configuration change notification (#121).
+#[derive(Debug, Deserialize, Default)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct InitializationOptions {
+    pub(crate) log_level: Option<crate::logging::LogLevel>,
+    pub(crate) dependency_log_levels: Option<String>,
+}
+
+impl InitializationOptions {
+    pub(crate) fn from_value(value: Value) -> Self {
+        serde_json::from_value(value)
+            .map_err(|err| {
+                tracing::error!("Failed to deserialize initialization options: {err}. Falling back to default settings.");
+            })
+            .unwrap_or_default()
+    }
+}

editors/code/package.json

@@ -35,6 +35,29 @@
 				]
 			}
 		],
+		"configuration": {
+			"properties": {
+				"air.logLevel": {
+					"default": null,
+					"markdownDescription": "Controls the log level of the language server.\n\n**This setting requires a restart to take effect.**",
+					"enum": [
+					  "error",
+					  "warning",
+					  "info",
+					  "debug",
+					  "trace"
+					],
+					"scope": "application",
+					"type": "string"
+				},
+				"air.dependencyLogLevels": {
+					"default": null,
+					"markdownDescription": "Controls the log level of the Rust crates that the language server depends on.\n\n**This setting requires a restart to take effect.**",
+					"scope": "application",
+					"type": "string"
+				}
+			}
+		},
 		"configurationDefaults": {
 			"[r]": {
 				"editor.defaultFormatter": "Posit.air"

editors/code/src/lsp.ts

@@ -1,6 +1,7 @@
 import * as vscode from "vscode";
 import * as lc from "vscode-languageclient/node";
 import { default as PQueue } from "p-queue";
+import { getInitializationOptions } from "./settings";
 
 // All session management operations are put on a queue. They can't run
 // concurrently and either result in a started or stopped state. Starting when
@@ -52,7 +53,9 @@ export class Lsp {
 			return;
 		}
 
-		let options: lc.ServerOptions = {
+		const initializationOptions = getInitializationOptions("air");
+
+		let serverOptions: lc.ServerOptions = {
 			command: "air",
 			args: ["language-server"],
 		};
@@ -71,13 +74,14 @@ export class Lsp {
 					vscode.workspace.createFileSystemWatcher("**/*.[Rr]"),
 			},
 			outputChannel: this.channel,
+			initializationOptions: initializationOptions,
 		};
 
 		const client = new lc.LanguageClient(
 			"airLanguageServer",
 			"Air Language Server",
-			options,
-			clientOptions,
+			serverOptions,
+			clientOptions
 		);
 		await client.start();
 

editors/code/src/settings.ts

@@ -0,0 +1,41 @@
+import { ConfigurationScope, workspace, WorkspaceConfiguration } from "vscode";
+
+type LogLevel = "error" | "warn" | "info" | "debug" | "trace";
+
+// This is a direct representation of the Client settings sent to the Server in the
+// `initializationOptions` field of `InitializeParams`. These are only pulled at the
+// user level since they are global settings on the server side (and are scoped to
+// `"scope": "application"` in `package.json` so they can't even be set at workspace level).
+export type InitializationOptions = {
+	logLevel?: LogLevel;
+	dependencyLogLevels?: string;
+};
+
+export function getInitializationOptions(
+	namespace: string
+): InitializationOptions {
+	const config = getConfiguration(namespace);
+
+	return {
+		logLevel: getOptionalUserValue<LogLevel>(config, "logLevel"),
+		dependencyLogLevels: getOptionalUserValue<string>(
+			config,
+			"dependencyLogLevels"
+		),
+	};
+}
+
+function getOptionalUserValue<T>(
+	config: WorkspaceConfiguration,
+	key: string
+): T | undefined {
+	const inspect = config.inspect<T>(key);
+	return inspect?.globalValue;
+}
+
+function getConfiguration(
+	config: string,
+	scope?: ConfigurationScope
+): WorkspaceConfiguration {
+	return workspace.getConfiguration(config, scope);
+}