7cd58b06c7
* Add an error handler to ensure the Redis server connection is forcibly closed * Disable the Redis offline queue and retries
102 lines
3.4 KiB
JavaScript
102 lines
3.4 KiB
JavaScript
const Redis = require('redis')
|
|
|
|
const { REDIS_MIN_DB, REDIS_MAX_DB } = process.env
|
|
|
|
// By default, every Redis instance supports database numbers 0 - 15
|
|
const redisMinDb = REDIS_MIN_DB || 0
|
|
const redisMaxDb = REDIS_MAX_DB || 15
|
|
|
|
function formatRedisError (error) {
|
|
const errorCode = error ? error.code : null
|
|
const errorName = error ? error.constructor.name : 'Error'
|
|
const errorMsg = error ? error.toString() : 'unknown error'
|
|
const preamble = errorName + (errorCode ? ` with code "${errorCode}"` : '')
|
|
return preamble + ': ' + errorMsg
|
|
}
|
|
|
|
module.exports = function createClient (options = {}) {
|
|
const { db, name, url } = options
|
|
|
|
// If no Redis URL is provided, bail out
|
|
// NOTE: Could support other options like `host`, `port`, and `path` but
|
|
// choosing not to for the time being!
|
|
if (!url) return null
|
|
|
|
// Verify database number is within range
|
|
if (db != null) {
|
|
if (!Number.isInteger(db) || db < redisMinDb || db > redisMaxDb) {
|
|
throw new TypeError(
|
|
`Redis database number must be an integer between ${redisMinDb} and ${redisMaxDb} but was: ${JSON.stringify(db)}`
|
|
)
|
|
}
|
|
}
|
|
|
|
// Create the client
|
|
const client = Redis.createClient(url, {
|
|
// Only add this configuration for TLS-enabled Redis URL values.
|
|
// Otherwise, it breaks for local Redis instances without TLS enabled.
|
|
...url.startsWith('rediss://') && {
|
|
tls: {
|
|
// Required for production Heroku Redis
|
|
rejectUnauthorized: false
|
|
}
|
|
},
|
|
|
|
// Any running command that is unfulfilled when a connection is lost should
|
|
// NOT be retried after the connection has been reestablished.
|
|
retry_unfulfilled_commands: false,
|
|
|
|
// If we failed to send a new command during a disconnection, do NOT
|
|
// enqueue it to send later after the connection has been [re-]established.
|
|
// This is also critical to preventing a backend pile-up!
|
|
enable_offline_queue: false,
|
|
|
|
// Expand whatever other options and overrides were provided
|
|
...options
|
|
})
|
|
|
|
// Handle connection errors to prevent killing the Node.js process
|
|
client.on('error', (connectError) => {
|
|
try {
|
|
// Forcibly close the connection to the Redis server.
|
|
// Allow all still running commands to silently fail immediately.
|
|
client.end(false)
|
|
} catch (disconnectError) {
|
|
// Swallow any failure
|
|
}
|
|
})
|
|
|
|
// If a `name` was provided, use it in the prefix for logging event messages
|
|
const logPrefix = '[redis' + (name ? ` (${name})` : '') + ']'
|
|
|
|
// Add event listeners for basic logging
|
|
client.on('connect', () => { console.log(logPrefix, 'Connection opened') })
|
|
client.on('ready', () => { console.log(logPrefix, 'Ready to receive commands') })
|
|
client.on(
|
|
'reconnecting',
|
|
({
|
|
attempt,
|
|
delay,
|
|
// The rest are unofficial properties but currently supported
|
|
error,
|
|
total_retry_time: totalRetryTime,
|
|
times_connected: timesConnected
|
|
}) => {
|
|
console.log(
|
|
logPrefix,
|
|
'Reconnecting,',
|
|
`attempt ${attempt}`,
|
|
`with ${delay} delay`,
|
|
`due to ${formatRedisError(error)}.`,
|
|
`Elapsed time: ${totalRetryTime}.`,
|
|
`Successful connections: ${timesConnected}.`
|
|
)
|
|
}
|
|
)
|
|
client.on('end', () => { console.log(logPrefix, 'Connection closed') })
|
|
client.on('warning', (msg) => { console.warn(logPrefix, 'Warning:', msg) })
|
|
client.on('error', (error) => { console.error(logPrefix, formatRedisError(error)) })
|
|
|
|
return client
|
|
}
|