Goal: Simulate how a Node.js application reacts to timeouts.
Solution: Use toxiproxy and its timeout “toxic” with the value of 0, i.e. the connection won’t close, and data will be delayed until the toxic is removed.
The steps:
- Start toxiproxy, exposing the port
6666that we intend to use aslocalhost:6666:
docker pull shopify/toxiproxy docker run --name=toxiproxy --rm --expose 6666 -p 6666:6666 -it shopify/toxiproxy
(If I was on Linux and not OSX then I could use --net=host and wouldn’t need to expose and/or map the port.)
- Tell toxiproxy to serve request att
6666via an upstream service:
docker exec -it toxiproxy /bin/sh / # cd /go/bin/ /go/bin # ./toxiproxy-cli create upstream -l 0.0.0.0:6666 -u google.com:443
- Modify your code to access the local port
6666and test that everything works.
Since we want to access Google via HTTPS, we would get a certificate error when accessing it via localhost:6666 so we will add an alias to our local s /etc/hosts:
127.0.0.1 proxied.google.com
and use
https://proxied.google.com:6666 in our connecting code (instead of the https://google.com:443 we had there before). Verify that it works and the code gets a response as expected.
- Tell toxiproxy to have an infinite timeout for this service
Continuing our toxiproxy configuration from step 2:
./toxiproxy-cli toxic add -t timeout -a timeout=0 upstream
(Alternatively, e.g. timeout=100; then the connection will be closed after 100 ms.)
- Trigger your code again. You should get a timeout now.
Tip: You can simulate the service being down via disabling the proxy:
./toxiproxy-cli toggle upstream
