feat: use file watchers to track some setup statuses (#47)

Setup statuses for LS CLI authentication and AWS profile configuration
are now checked via file watchers instead of periodic checks.

It's still pending to improve the algorithm that checks for both the LS
CLI installation and the LS CLI license.

Author: skyrpex

package-lock.json

@@ -110,7 +110,8 @@
 		"package": "node build/extension.mjs --production",
 		"pretest": "npm run compile",
 		"check-types": "tsc",
-		"lint": "eslint .",
+		"lint": "eslint",
+		"format": "biome check",
 		"test": "vscode-test",
 		"compile:font": "node build/icon-font.mjs"
 	},
@@ -126,6 +127,7 @@
 		"@vscode/test-cli": "^0.0.11",
 		"@vscode/test-electron": "^2.5.2",
 		"@vscode/vsce": "^3.6.0",
+		"chokidar": "^4.0.3",
 		"esbuild": "^0.25.9",
 		"eslint": "^9.35.0",
 		"eslint-plugin-import": "^2.32.0",

package.json

@@ -84,7 +84,7 @@ async function redirectToLocalStack(): Promise<{ cancelled: boolean }> {
 	return { cancelled: !openSuccessful };
 }
 
-const LOCALSTACK_AUTH_FILENAME = `${os.homedir()}/.localstack/auth.json`;
+export const LOCALSTACK_AUTH_FILENAME = `${os.homedir()}/.localstack/auth.json`;
 const LOCALSTACK_AUTH_FILENAME_READABLE = LOCALSTACK_AUTH_FILENAME.replace(
 	`${os.homedir()}/`,
 	"~/",

src/utils/authenticate.ts

@@ -35,7 +35,9 @@ const LOCALSTACK_CREDENTIALS_PROPERTIES = {
 	aws_secret_access_key: "test",
 };
 
-const AWS_DIRECTORY = path.join(os.homedir(), ".aws");
+export const AWS_DIRECTORY = path.join(os.homedir(), ".aws");
+export const AWS_CONFIG_FILENAME = path.join(AWS_DIRECTORY, "config");
+export const AWS_CREDENTIALS_FILENAME = path.join(AWS_DIRECTORY, "credentials");
 
 async function overrideSelection(
 	filesToModify: string[],
@@ -464,13 +466,13 @@ export async function configureAwsProfiles(options: {
 
 export async function checkIsProfileConfigured(): Promise<boolean> {
 	try {
-		const awsConfigFilename = path.join(AWS_DIRECTORY, "config");
-		const awsCredentialsFilename = path.join(AWS_DIRECTORY, "credentials");
-
 		const [{ section: configSection }, { section: credentialsSection }] =
 			await Promise.all([
-				getProfile(awsConfigFilename, LOCALSTACK_CONFIG_PROFILE_NAME),
-				getProfile(awsCredentialsFilename, LOCALSTACK_CREDENTIALS_PROFILE_NAME),
+				getProfile(AWS_CONFIG_FILENAME, LOCALSTACK_CONFIG_PROFILE_NAME),
+				getProfile(
+					AWS_CREDENTIALS_FILENAME,
+					LOCALSTACK_CREDENTIALS_PROFILE_NAME,
+				),
 			]);
 
 		const [configNeedsOverride, credentialsNeedsOverride] = await Promise.all([

src/utils/configure-aws.ts

@@ -0,0 +1,23 @@
+/**
+ * Creates a function that calls the given callback immediately once.
+ *
+ * Multiple calls during the same tick are ignored.
+ *
+ * @param callback - The callback to call.
+ * @returns A function that calls the callback immediately once.
+ */
+export function immediateOnce<T>(callback: () => T): () => void {
+	let timeout: NodeJS.Immediate | undefined;
+
+	return () => {
+		if (timeout) {
+			return;
+		}
+
+		timeout = setImmediate(() => {
+			void Promise.resolve(callback()).finally(() => {
+				timeout = undefined;
+			});
+		});
+	};
+}

src/utils/immediate-once.ts

@@ -1,7 +1,36 @@
+import { homedir, platform } from "node:os";
+import { join } from "node:path";
+
 import type { CancellationToken, LogOutputChannel } from "vscode";
 
 import { execLocalStack } from "./cli.ts";
 
+/**
+ * See https://github.com/localstack/localstack/blob/de861e1f656a52eaa090b061bd44fc1a7069715e/localstack-core/localstack/utils/files.py#L38-L55.
+ * @returns The cache directory for the current platform.
+ */
+const cacheDirectory = () => {
+	switch (platform()) {
+		case "win32":
+			return join(process.env.LOCALAPPDATA!, "cache");
+		case "darwin":
+			return join(homedir(), "Library", "Caches");
+		default:
+			return process.env.XDG_CACHE_HOME ?? join(homedir(), ".cache");
+	}
+};
+
+/**
+ * The file that contains the license information of the LocalStack CLI.
+ *
+ * The license file is stored in the cache directory for the current platform.
+ */
+export const LICENSE_FILENAME = join(
+	cacheDirectory(),
+	"localstack-cli",
+	"license.json",
+);
+
 const LICENSE_VALIDITY_MARKER = "license validity: valid";
 
 export async function checkIsLicenseValid(outputChannel: LogOutputChannel) {