Created
September 16, 2022 03:21
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Salesforce Function - Caching Example
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export default async function (event, context, logger) { | |
logger.info(`Invoking Datafunction with payload ${JSON.stringify(event.data || {})}`); | |
const redis = await redisConnect(); | |
let cached = {}; | |
// Check Redis for cached entry first | |
let big_biz_count = await redis.get(`big_biz`); | |
if (big_biz_count) { | |
// If cached entry found, return it and be done. | |
logger.info(`Found cache entry = ${big_biz_count}`); | |
cached = "true" | |
redis.quit(); | |
return { big_biz_count, cached } | |
} else { | |
// If cached entry not found, then: | |
// 1. Run the Postgres query | |
// 2. Store the result in Redis | |
// 3. Return the result and be done | |
logger.info(`did not find in cache, returned ${big_biz_count}`); | |
cached = "false" | |
const pg = await pgConnect(); | |
const { rows } = await pg.query('SELECT COUNT(*) FROM company WHERE employees>10000;'); | |
big_biz_count = rows[0].count.toString(); | |
redis.set(`big_biz`, big_biz_count, { | |
EX: 30, // seconds to keep before expiring | |
NX: true | |
}); | |
// Close the connections | |
redis.quit(); | |
pg.end(); | |
// Return the value from Postgres, now stored in Redis | |
return { big_biz_count, cached } | |
} | |
} | |
/* Helper functions */ | |
// Connect to PostgreSQL | |
async function pgConnect() { | |
const DATABASE_URL = process.env.DATABASE_URL; | |
if (!DATABASE_URL) { | |
throw new Error("DATABASE_URL is not set"); | |
} | |
const client = new Client({ | |
connectionString: DATABASE_URL, | |
ssl: { | |
rejectUnauthorized: false | |
} | |
}); | |
await client.connect(); | |
return client; | |
} | |
// Connect to Redis | |
async function redisConnect() { | |
const REDIS_URL = process.env.REDIS_URL; | |
if (!REDIS_URL) { | |
throw new Error("REDIS_URL is not set"); | |
} | |
const redis = createClient({ | |
url: process.env.REDIS_URL, | |
socket: { | |
tls: true, | |
rejectUnauthorized: false | |
} | |
}); | |
await redis.connect(); | |
redis.on('error', err => { | |
console.log('Error ' + err); | |
}); | |
return redis; | |
} |
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