Fix redis race condition

packages/commerce/src/sync.ts

@@ -7,7 +7,7 @@ import pino from "pino";
 
 const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
 
-type MainProduct = {
+type MetaPrintfulProduct = {
     name: string;
     externalId: string;
     colors: Set<string>;
@@ -18,8 +18,7 @@ type MainProduct = {
 };
 
 type SyncState = {
-    isSyncing: boolean;
-    syncingIds: number[];
+    printfulProductIds: number[];
 };
 
 export class ProductSyncer {
@@ -33,14 +32,15 @@ export class ProductSyncer {
         this.log = (log ?? pino({ level: "silent" })).child({ component: "ProductSyncer" });
     }
 
-    async sync(printfulProductId?: number) {
-        const syncStart = Date.now();
+    async sync(printfulProductId?: number): Promise<boolean> {
+        const canRun = await this.run();
+        if (!canRun) return false;
+
         try {
+            const syncStart = Date.now();
             if (printfulProductId) this.log.info({ printfulProductId }, "sync started");
             else this.log.info("sync started");
 
-            await this.setState({ isSyncing: true, syncingIds: [] });
-
             this.log.debug("populating webflow products");
             const webflowProducts: Webflow.Products.ProductAndSkus[] = await this.webflow.Products.list({ forceAll: true });
 
@@ -59,7 +59,7 @@ export class ProductSyncer {
             }
 
             this.log.info({ count: printfulProducts.length }, "generating meta printful products");
-            const metaPrintfulProducts: MainProduct[] = [];
+            const metaPrintfulProducts: MetaPrintfulProduct[] = [];
             for (const printfulProduct of printfulProducts) {
                 const mainProductName = this.getMainProductName(
                     printfulProduct.name,
@@ -93,8 +93,7 @@ export class ProductSyncer {
             for (const metaPrintfulProduct of metaPrintfulProducts) {
                 this.log.info({ name: metaPrintfulProduct.name }, "syncing meta printful product");
                 await this.setState({
-                    isSyncing: true,
-                    syncingIds: metaPrintfulProduct.variants.map(
+                    printfulProductIds: metaPrintfulProduct.variants.map(
                         (v) => v.product.sync_product.id,
                     ),
                 });
@@ -291,22 +290,13 @@ export class ProductSyncer {
             this.log.info({ durationMs: Date.now() - syncStart }, "sync complete");
         } finally {
             try {
-                await this.setState({ isSyncing: false, syncingIds: [] });
+                await redis.del("commerce:sync:lock");
+                await redis.del("commerce:sync:state");
             } catch {
                 this.log.error("failed to reset sync state");
             }
         }
-    }
-
-    async setState(state: SyncState) {
-        await redis.set("commerce:sync:state", JSON.stringify(state));
-        await redis.expire("commerce:sync:state", 1800);
-    }
-
-    async getState(): Promise<SyncState> {
-        const val = await redis.get("commerce:sync:state");
-        if (val) return JSON.parse(val);
-        return { isSyncing: false, syncingIds: [] };
+        return true;
     }
 
     findColorInProductName(productName: string): string {
@@ -322,4 +312,22 @@ export class ProductSyncer {
             return productName;
         }
     }
+
+    async isRunning(): Promise<boolean> {
+        return !!await redis.get("commerce:sync:lock");
+    }
+
+    async getState(): Promise<SyncState> {
+        const val = await redis.get("commerce:sync:state");
+        if (val) return JSON.parse(val);
+        return { printfulProductIds: [] };
+    }
+
+    private async setState(state: SyncState) {
+        await redis.set("commerce:sync:state", JSON.stringify(state), "EX", 1800);
+    }
+
+    private async run(): Promise<boolean> {
+        return !!await redis.set("commerce:sync:lock", "1", "NX", "EX", "1800");
+    }
 }