Hit localhost from a batect-spun container? :)

[adameichelkraut]

TLDR; I have a separate web server that might be running in localhost that I wish to hit with my batect-spun-up container! Anyone have any snippets for how to do this properly?

Tried sifting lightly through the discussions -- wondered if this was already answered. I also did some light googling on the topic at large within the Docker-verse and it seems folks have found luck by either setting the network to host and fiddling with setting some additional_hosts on the container to point the container to the host machine's network.

I've tried using --use-network=host with batect, however I get:

Error response from daemon: network-scoped alias is supported only for containers in user defined networks

I've also tried adding something like this to the container's config:

    ...
    additional_hosts:
      host.docker.internal: host-gateway

However, I'm thinking that this above needs to be paired with the use network host.

Maybe I'm missing something in the docs? Look forward to chatting! Thanks!

[charleskorn]

You should be able to use host.docker.internal on Mac and Windows hosts (and possibly Linux hosts too) without any configuration or switching to host networking. What happens when you try to use this hostname?

One thing to check: the target web server on your machine may need to be listening on all local addresses, not just the loopback address. (ie. check if it is listening on 0.0.0.0, not 127.0.0.1).

Similarly, I'm not sure if host.docker.internal supports IPv6, so check if your web server is listening on IPv6 or IPv4.