refactor(core): Mark deprecations for v2 (#11817)

packages/cli/src/deprecation/deprecation.service.ts

@@ -0,0 +1,85 @@
+import { ApplicationError } from 'n8n-workflow';
+import { Service } from 'typedi';
+
+import { Logger } from '@/logging/logger.service';
+
+type EnvVarName = string;
+
+type Deprecation = {
+	/** Name of the deprecated env var. */
+	envVar: EnvVarName;
+
+	/** Message to display when the deprecated env var is currently in use. */
+	message: string;
+
+	/** Function to identify the specific value in the env var that is deprecated. */
+	checkValue?: (value: string) => boolean;
+};
+
+const SAFE_TO_REMOVE = 'Remove this environment variable; it is no longer needed.';
+
+/** Responsible for warning about use of deprecated env vars. */
+@Service()
+export class DeprecationService {
+	private readonly deprecations: Deprecation[] = [
+		{ envVar: 'N8N_BINARY_DATA_TTL', message: SAFE_TO_REMOVE },
+		{ envVar: 'N8N_PERSISTED_BINARY_DATA_TTL', message: SAFE_TO_REMOVE },
+		{ envVar: 'EXECUTIONS_DATA_PRUNE_TIMEOUT', message: SAFE_TO_REMOVE },
+		{
+			envVar: 'N8N_BINARY_DATA_MODE',
+			message: '`default` is deprecated. Please switch to `filesystem` mode.',
+			checkValue: (value: string) => value === 'default',
+		},
+		{ envVar: 'N8N_CONFIG_FILES', message: 'Please use .env files or *_FILE env vars instead.' },
+		{
+			envVar: 'DB_TYPE',
+			message: 'MySQL and MariaDB are deprecated. Please migrate to PostgreSQL.',
+			checkValue: (value: string) => ['mysqldb', 'mariadb'].includes(value),
+		},
+		{
+			envVar: 'N8N_SKIP_WEBHOOK_DEREGISTRATION_SHUTDOWN',
+			message: `n8n no longer deregisters webhooks at startup and shutdown. ${SAFE_TO_REMOVE}`,
+		},
+	];
+
+	/** Runtime state of deprecated env vars. */
+	private readonly state: Record<EnvVarName, { inUse: boolean }> = {};
+
+	constructor(private readonly logger: Logger) {}
+
+	warn() {
+		this.deprecations.forEach((d) => {
+			const envValue = process.env[d.envVar];
+			this.state[d.envVar] = {
+				inUse: d.checkValue
+					? envValue !== undefined && d.checkValue(envValue)
+					: envValue !== undefined,
+			};
+		});
+
+		const inUse = Object.entries(this.state)
+			.filter(([, d]) => d.inUse)
+			.map(([envVar]) => {
+				const deprecation = this.deprecations.find((d) => d.envVar === envVar);
+				if (!deprecation) {
+					throw new ApplicationError(`Deprecation not found for env var: ${envVar}`);
+				}
+				return deprecation;
+			});
+
+		if (inUse.length === 0) return;
+
+		const header = `The following environment variable${
+			inUse.length === 1 ? ' is' : 's are'
+		} deprecated and will be removed in an upcoming version of n8n. Please take the recommended actions to update your configuration`;
+		const deprecations = inUse
+			.map(({ envVar, message }) => ` - ${envVar} -> ${message}\n`)
+			.join('');
+
+		this.logger.warn(`\n${header}:\n${deprecations}`);
+	}
+
+	isInUse(envVar: string) {
+		return this.state[envVar]?.inUse ?? false;
+	}
+}