From 6020f4bdb43a7ce7e19ca31ace8a4588ef65eb8b Mon Sep 17 00:00:00 2001
From: rishtigupta <rishti@momentohq.com>
Date: Tue, 16 Apr 2024 12:17:10 -0700
Subject: [PATCH] feat: add incr api

---
 src/momento-redis-adapter.ts | 16 +++++++++
 test/increment.test.ts       | 70 ++++++++++++++++++++++++++++++++++++
 test/integration-setup.ts    |  5 +++
 3 files changed, 91 insertions(+)
 create mode 100644 test/increment.test.ts

diff --git a/src/momento-redis-adapter.ts b/src/momento-redis-adapter.ts
index 94831c6..671ebdd 100644
--- a/src/momento-redis-adapter.ts
+++ b/src/momento-redis-adapter.ts
@@ -9,6 +9,7 @@ import {
   CacheDictionarySetFields,
   CacheFlush,
   CacheGet,
+  CacheIncrement,
   CacheItemGetTtl,
   CacheSet,
   CacheSetIfAbsent,
@@ -91,6 +92,8 @@ export interface MomentoIORedis {
     nx: 'NX'
   ): Promise<'OK' | null>;
 
+  incr(key: RedisKey): Promise<number | string>;
+
   ttl(key: RedisKey): Promise<number | null>;
 
   pttl(key: RedisKey): Promise<number | null>;
@@ -395,6 +398,19 @@ export class MomentoRedisAdapter
     return null;
   }
 
+  async incr(key: RedisKey): Promise<number | string> {
+    const rsp = await this.momentoClient.increment(this.cacheName, key);
+    if (rsp instanceof CacheIncrement.Success) {
+      return rsp.value();
+    } else if (rsp instanceof CacheIncrement.Error) {
+      this.emitError('incr', rsp.message(), rsp.errorCode());
+      return rsp.message();
+    } else {
+      this.emitError('incr', `unexpected-response ${rsp.toString()}`);
+      return rsp.toString();
+    }
+  }
+
   async hset(
     ...args: [
       RedisKey,
diff --git a/test/increment.test.ts b/test/increment.test.ts
new file mode 100644
index 0000000..60f5c22
--- /dev/null
+++ b/test/increment.test.ts
@@ -0,0 +1,70 @@
+import {SetupIntegrationTest} from './integration-setup';
+import {v4} from 'uuid';
+
+const {client} = SetupIntegrationTest();
+
+describe('increment', () => {
+  it('should increment the value of the key by 1 if the key exists', async () => {
+    const key = v4();
+    const value = 5;
+
+    // Set initial key value
+    await client.set(key, value);
+
+    // Increment the value of the key
+    const incrResp = await client.incr(key);
+    expect(incrResp).toBe(value + 1);
+  });
+
+  it('should increment the value of the key to 1 if the key does not exists', async () => {
+    const key = v4();
+
+    // Increment the value of the key that is not set
+    const incrResp = await client.incr(key);
+    expect(incrResp).toBe(1);
+  });
+
+  it('should error out if the key contains a value of wrong type or contains a string that can be represented as integer', async () => {
+    const key = v4();
+    const value = 'monkey';
+
+    // Set initial key value
+    await client.set(key, value);
+
+    // Increment the value of the key that is not set
+    try {
+      await client.incr(key);
+    } catch (error) {
+      if (process.env.MOMENTO_ENABLED === 'true') {
+        const momentoError = error as {
+          code: string;
+          context: {code: string; msg: string; op: string; platform: string};
+        };
+        expect(momentoError.code).toBe('ERR_UNHANDLED_ERROR');
+        expect(momentoError.context.code).toBe('FAILED_PRECONDITION_ERROR');
+        expect(momentoError.context.msg).toBe(
+          "System is not in a state required for the operation's execution: 9 FAILED_PRECONDITION: failed to parse value into long"
+        );
+        expect(momentoError.context.op).toBe('incr');
+        expect(momentoError.context.platform).toBe('momento');
+      } else {
+        expect(error).toBeInstanceOf(Error);
+        expect((error as Error).message).toBe(
+          'ERR value is not an integer or out of range'
+        );
+      }
+    }
+  });
+
+  it('should increment the value of key that contains a string that can be represented as integer', async () => {
+    const key = v4();
+    const value = '10';
+
+    // Set initial key value
+    await client.set(key, value);
+
+    // Increment the value of the key that is not set
+    const incrResp = await client.incr(key);
+    expect(incrResp).toBe(11);
+  });
+});
diff --git a/test/integration-setup.ts b/test/integration-setup.ts
index fd941c3..32cf0a7 100644
--- a/test/integration-setup.ts
+++ b/test/integration-setup.ts
@@ -86,6 +86,11 @@ function setupIntegrationTestWithMomento() {
     }
   );
 
+  // If using Momento with Redis backend, close the Redis connection
+  afterAll(async () => {
+    await momentoNodeRedisClient.quit();
+  });
+
   return {client: momentoNodeRedisClient};
 }