[CAMEL-12103] Camel unable to shutdown gracefully because Netty4 consumer keep receiving and adding inflight exchanges

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.15.2
• Fix Version/s: 2.21.0
• Component/s: camel-netty4
• Estimated Complexity: Unknown
• Assignee: Claus Ibsen
• Reporter: Yih Tsern
• Created: 27/Dec/17 09:36
• Updated: 03/Jan/18 08:57
• Resolved: 03/Jan/18 08:57

Description

I'm using this URI: netty4:tcp://localhost:8888?sync=false&textline=true

And I have this issue when initiating Camel shutdown using DefaultShutdownStrategy:

1. Camel suspends NettyConsumer (SingleTCPNettyServerBootstrapFactory), which only stops the "main" Netty channel, but not the other Netty channels (i.e. socket connections)
2. Camel waits for routes to be empty of inflight & pending exchanges
3. Those other Netty channels kept receiving data, which are turned into new exchanges
   • As long as the TCP clients keep sending data into the channels + exchanges completing slower than send rate, routes will never be empty of inflight & pending exchanges
4. Forced shutdown after 5 minutes (timed out)

To simulate the issue

1. Run the attached tcp-server.camel Groovy script: groovy tcp-server.camel
2. After that has started, run the attached tcp-client.groovy: groovy tcp-client.groovy
3. After tcp-client starts sending data over, stop the tcp-server (CTRL+C in Windows)
4. You should see something like this:
   cmd

   INFO - Apache Camel 2.15.2 (CamelContext: camel-1) started in 1.015 seconds
   INFO - Hey 0
   INFO - Hey 1
   INFO - Hey 2
   INFO - Hey 3
   INFO - Apache Camel 2.15.2 (CamelContext: camel-1) is shutting down
   INFO - Starting to graceful shutdown 1 routes (timeout 300 seconds)
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 300 seconds.
   INFO - Hey 4
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 299 seconds.
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 298 seconds.
   INFO - Hey 5
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 297 seconds.
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 296 seconds.
   INFO - Hey 6
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 295 seconds.
   INFO - Waiting as there are still 1 inflight and pending exchanges to complete,
   timeout in 294 seconds.
   ...