Refactor VPN proxy client implementation

src/server/features/routing/routeRulesService.ts

@@ -0,0 +1,119 @@
+import { isDeepStrictEqual } from 'node:util';
+
+import type { RouteRule, StoredState } from '../../../shared/contracts/state.js';
+import { HarborError } from '../../../shared/errors.js';
+import { normalizeRouteRules } from '../../../shared/routingRules.js';
+import type { RuntimeCommandResult } from '../connection/index.js';
+import { finishRollback } from '../../services/rollback.js';
+
+interface RouteRulesDependencies {
+  state: {
+    read(): StoredState;
+    update(mutator: (state: StoredState) => Record<string, unknown>): StoredState;
+  };
+  subscription: { readConfig(): unknown | null };
+  config: {
+    build(subscriptionConfig: unknown, selectedServerId: string, routeRules: RouteRule[]): unknown;
+    read(): string | null;
+    write(value: unknown): void;
+    restore(value: string): void;
+    remove(): void;
+  };
+  runtime: {
+    isRunning(): Promise<boolean>;
+    applyCommand(): Promise<RuntimeCommandResult>;
+    restoreRunning(): Promise<unknown>;
+  };
+  serialize<T>(operation: () => Promise<T>): Promise<T>;
+  runOperation<T>(operation: () => Promise<T>): Promise<T>;
+}
+
+export function createRouteRulesService(dependencies: RouteRulesDependencies) {
+  const applyRules = async (previousState: StoredState, routeRules: RouteRule[]) => {
+    const subscriptionConfig = dependencies.subscription.readConfig();
+    if (!previousState.selectedServerId || !subscriptionConfig) {
+      let stateCommitStarted = false;
+      try {
+        stateCommitStarted = true;
+        dependencies.state.update((state) => ({
+          ...state,
+          routeRules,
+          routeRulesRevision: state.routeRulesRevision + 1,
+        }));
+      } catch (error) {
+        await finishRollback(error, [
+          ...(stateCommitStarted ? [{ run: () => dependencies.state.update(() => previousState) }] : []),
+        ], 'Route rules rollback failed');
+      }
+      return;
+    }
+
+    const candidateConfig = dependencies.config.build(
+      subscriptionConfig,
+      previousState.selectedServerId,
+      routeRules,
+    );
+    const previousConfig = dependencies.config.read();
+    const wasRunning = await dependencies.runtime.isRunning();
+    let configMutationStarted = false;
+    let runtimeMutationStarted = false;
+    let stateCommitStarted = false;
+
+    try {
+      configMutationStarted = true;
+      dependencies.config.write(candidateConfig);
+      if (wasRunning) {
+        const command = await dependencies.runtime.applyCommand();
+        runtimeMutationStarted = command.mutationStarted;
+        if (!command.ok) throw command.error;
+      }
+      stateCommitStarted = true;
+      dependencies.state.update((state) => ({
+        ...state,
+        routeRules,
+        ...(wasRunning ? { appliedRouteRules: routeRules } : {}),
+        routeRulesRevision: state.routeRulesRevision + 1,
+      }));
+    } catch (error) {
+      await finishRollback(error, [
+        ...(configMutationStarted ? [{
+          run: () => previousConfig === null
+            ? dependencies.config.remove()
+            : dependencies.config.restore(previousConfig),
+        }] : []),
+        ...(wasRunning && runtimeMutationStarted ? [{
+          run: () => dependencies.runtime.restoreRunning(),
+          runtime: true,
+        }] : []),
+        ...(stateCommitStarted ? [{ run: () => dependencies.state.update(() => previousState) }] : []),
+      ], 'Route rules rollback failed');
+    }
+  };
+
+  const update = (rules: unknown, expectedRulesRevision: unknown, expectedRevision: unknown) => {
+    let routeRules: RouteRule[];
+    try {
+      routeRules = normalizeRouteRules(rules, { strict: true }) as RouteRule[];
+    } catch (cause) {
+      throw new HarborError('REQUEST_INVALID', { cause });
+    }
+    const rulesRevision = expectedRulesRevision ?? expectedRevision;
+    if (!Number.isSafeInteger(rulesRevision) || Number(rulesRevision) < 0) {
+      throw new HarborError('REQUEST_INVALID');
+    }
+
+    return dependencies.serialize(async () => {
+      const current = dependencies.state.read();
+      const currentRevision = expectedRulesRevision == null
+        ? current.revision
+        : current.routeRulesRevision;
+      if (currentRevision !== rulesRevision) throw new HarborError('STATE_CONFLICT');
+      if (isDeepStrictEqual(current.routeRules, routeRules)) return;
+      await dependencies.runOperation(() => applyRules(current, routeRules));
+    });
+  };
+
+  return { update };
+}
+
+export type RouteRulesService = ReturnType<typeof createRouteRulesService>;