I’m attempting to scale up n8n following the official instruction, I have the following setup locally via docker-compose:
- n8n (main process)
- n8n (worker)
- Redis
- Postgres
Using a simple example workflow, it is able to execute successfully when triggered manually, and via cronjob trigger when EXECUTIONS_MODE is not set to queue.
However, when EXECUTIONS_MODE=queue is configured, the job executes successfully when triggered manually, but fails to execute when triggered by cronjob with the following log:
2021-09-07T02:40:59.020Z | error | Problem with execution 7: Cannot read property 'id' of undefined. Aborting. {"file":"WorkflowRunner.js"}
(node:7) UnhandledPromiseRejectionWarning: Error: Cannot read property 'id' of undefined
at Queue.onFailed (/usr/local/lib/node_modules/n8n/node_modules/bull/lib/job.js:516:18)
at Queue.emit (events.js:315:20)
at Queue.EventEmitter.emit (domain.js:467:12)
at Redis.messageHandler (/usr/local/lib/node_modules/n8n/node_modules/bull/lib/queue.js:444:14)
at Redis.emit (events.js:315:20)
at Redis.EventEmitter.emit (domain.js:467:12)
at DataHandler.handleSubscriberReply (/usr/local/lib/node_modules/n8n/node_modules/ioredis/built/DataHandler.js:80:32)
at DataHandler.returnReply (/usr/local/lib/node_modules/n8n/node_modules/ioredis/built/DataHandler.js:47:18)
at JavascriptRedisParser.returnReply (/usr/local/lib/node_modules/n8n/node_modules/ioredis/built/DataHandler.js:21:22)
at JavascriptRedisParser.execute (/usr/local/lib/node_modules/n8n/node_modules/redis-parser/lib/parser.js:544:14)
at Socket.<anonymous> (/usr/local/lib/node_modules/n8n/node_modules/ioredis/built/DataHandler.js:25:20)
at Socket.emit (events.js:315:20)
at Socket.EventEmitter.emit (domain.js:467:12)
at addChunk (internal/streams/readable.js:309:12)
at readableAddChunk (internal/streams/readable.js:284:9)
at Socket.Readable.push (internal/streams/readable.js:223:10)
at TCP.onStreamRead (internal/stream_base_commons.js:188:23)
(node:7) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 7)
I suspected the n8n main process’s --tunnel flag could be the cause, but the same issue persists even without the --tunnel flag. Perhaps I miss some configuration on the n8n worker? Thanks for the help in advance!
Here’s some more details on my setup:
Workflow used for testing
docker-compose
version: "3.8"
services:
n8n:
container_name: n8n
image: n8nio/n8n:0.135.2
command: n8n start --tunnel
restart: always
environment:
# ----- redis ----- #
QUEUE_BULL_REDIS_HOST: n8n_redis
QUEUE_BULL_REDIS_PORT: 6379
# ----- postgres ----- #
DB_TYPE: postgresdb
DB_TABLE_PREFIX: n8n
DB_POSTGRESDB_DATABASE: n8n
DB_POSTGRESDB_HOST: n8n_postgres
DB_POSTGRESDB_PORT: 5432
DB_POSTGRESDB_USER: admin
DB_POSTGRESDB_PASSWORD: thisisarandompassword
# ----- logging ----- #
N8N_LOG_LEVEL: verbose
# ----- scaling ----- #
EXECUTIONS_MODE: queue
ports:
- 5677:5678
n8n_worker:
container_name: n8n_worker
image: n8nio/n8n:0.135.2
command: n8n worker
restart: always
environment:
# ----- redis ----- #
QUEUE_BULL_REDIS_HOST: n8n_redis
QUEUE_BULL_REDIS_PORT: 6379
# ----- postgres ----- #
DB_TYPE: postgresdb
DB_POSTGRESDB_DATABASE: n8n
DB_POSTGRESDB_HOST: n8n_postgres
DB_POSTGRESDB_PORT: 5432
DB_POSTGRESDB_USER: admin
DB_POSTGRESDB_PASSWORD: thisisarandompassword
ports:
- 5676:5678
n8n_redis:
container_name: n8n_redis
image: redis:6.2.5-alpine
restart: always
ports:
- 6379:6379
n8n_postgres:
container_name: n8n_postgres
image: postgres:9.6.17-alpine
restart: always
ports:
- 5432:5432
environment:
POSTGRES_DB: n8n
POSTGRES_USER: admin
POSTGRES_PASSWORD: thisisarandompassword
