Natter Docker image misses natterutils module

[leleobhz]

Hello

Using natter latest docker tag logs the reuse_port is not available on platform. Testing inside container, I see the natterutils module:

# python3
Python 3.13.5 (main, Jun 25 2025, 18:55:22) [GCC 14.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from natterutils import reuse_port
Traceback (most recent call last):
  File "<python-input-0>", line 1, in <module>
    from natterutils import reuse_port
ModuleNotFoundError: No module named 'natterutils'

There is a reason to this module missing on container?

[MikeWang000000]

Hello👋

Feature of reusing port used by other process is only implemented on MicroPython platforms. The source of the module is here:
https://github.com/MikeWang000000/Natter/blob/master/micropython/cmodule/natterutils/modnatterutils.c

MicroPython builds are statically linked, which do not require docker environment. You can download the latest MicroPython build here (x86_64):
https://github.com/MikeWang000000/Natter/releases/latest/download/natter-linux-x86_64.tar.gz

For now, all docker containers are CPython based. If everything runs normally, you can safely ignore this debug message ;)

[leleobhz]

MicroPython builds are statically linked, which do not require docker environment

Requires if I run code in a Kubernetes environment - for example. I (want) to use Natter as a Sidecar container.

If everything runs normally, you can safely ignore this debug message ;)

Unfortunately does not. In fact I cannot listen on qbittorrent on same network of Natter with containers like they are today. SO_REUSEPORT helps on this and does not requires anything except use this statically linked MicroPython version. But in fact a mode that Natter only does the holepunch and notificates the script is also helpful - but out of scope of this PR.

[leleobhz]

I did a concept container to use micropython version:

FROM registry.access.redhat.com/ubi10/ubi:latest AS builder

ARG branch=master

RUN dnf install -y catatonit gcc make xz git-core patch

RUN git clone --single-branch --depth=1 --branch=${branch} https://github.com/MikeWang000000/Natter.git /tmp/natter \
 && cd /tmp/natter/micropython \
 && make -j $(nproc --ignore=1)

FROM scratch
FROM registry.access.redhat.com/ubi10/ubi-minimal:latest

COPY --from=builder /usr/libexec/catatonit/catatonit /catatonit
COPY --from=builder /tmp/natter/micropython/build/natter /natter

ENTRYPOINT ["/catatonit", "-g", "--", "/natter" ]
CMD [ "--help" ]

And as result:

❯ podman build --build-arg branch=2.2.1 -t localhost/teste:latest -f Containerfile .
[1/3] STEP 1/4: FROM registry.access.redhat.com/ubi10/ubi:latest AS builder
[1/3] STEP 2/4: ARG branch=master
--> Using cache dee7a06347dc9365c9d283eb7bea8978aced7b52bf05b9f3c274c8cf1d887f9a
--> dee7a06347dc
[1/3] STEP 3/4: RUN dnf install -y catatonit gcc make xz git-core patch
--> Using cache 700378b7bb194a0567ca1740229023655813b15cda2fb076efbb80225fdfa560
--> 700378b7bb19
[1/3] STEP 4/4: RUN git clone --single-branch --depth=1 --branch=${branch} https://github.com/MikeWang000000/Natter.git /tmp/natter  && cd /tmp/natter/micropython  && make -j $(nproc --ignore=1)
--> Using cache 24ba8cffd237330402624de5f6fd607dabeee08076c18d43abfa9ad3956f592e
--> 24ba8cffd237
[3/3] STEP 1/5: FROM registry.access.redhat.com/ubi10/ubi-minimal:latest
Trying to pull registry.access.redhat.com/ubi10/ubi-minimal:latest...
Getting image source signatures
Copying blob 4377b1aab54b done   |
Copying config 6212e75c11 done   |
Writing manifest to image destination
[3/3] STEP 2/5: COPY --from=builder /usr/libexec/catatonit/catatonit /catatonit
--> 9e93d70309ec
[3/3] STEP 3/5: COPY --from=builder /tmp/natter/micropython/build/natter /natter
--> 445e9c8a61f8
[3/3] STEP 4/5: ENTRYPOINT ["/catatonit", "-g", "--", "/natter" ]
--> 85338709cc02
[3/3] STEP 5/5: CMD [ "--help" ]
[3/3] COMMIT localhost/teste:latest
--> 81709e67baee
Successfully tagged localhost/teste:latest
81709e67baee063201f7105b1da04ace70b14d43a0d2ae429f429153a1cd452a

❯ podman run -it --rm --name teste localhost/teste:latest
usage: natter [--version] [--help] [--check] [-v] [-q] [-u] [-U]
              [-k <interval>] [-s <address>] [-h <address>] [-e <path>]
              [-i <interface>] [-b <port>] [-m <method>] [-t <address>]
              [-p <port>] [-r]

Expose your port behind full-cone NAT to the Internet.

options:
  --version, -V   show the version of Natter and exit
  --help          show this help message and exit
  --check         run natter-check and exit
  -v              verbose mode, printing debug messages
  -q              exit when mapped address is changed
  -u              UDP mode
  -U              enable UPnP/IGD discovery
  -k <interval>   seconds between each keep-alive
  -s <address>    hostname or address to STUN server
  -h <address>    hostname or address to keep-alive server
  -e <path>       script path for notifying mapped address

bind options:
  -i <interface>  network interface name or IP to bind
  -b <port>       port number to bind

forward options:
  -m <method>     forward method, common values are 'iptables', 'nftables',
                  'socat', 'gost' and 'socket'
  -t <address>    IP address of forward target
  -p <port>       port number of forward target
  -r              keep retrying until the port of forward target is open

❯ podman run -it --rm --name teste localhost/teste:latest --version
Natter 2.2.1

❯ podman run -it --rm --network=host --name teste localhost/teste:latest -p 8000
2026-03-11 12:41:53 [I] Natter v2.2.1
2026-03-11 12:42:01 [I]
2026-03-11 12:42:01 [I] tcp://<redacted_internal_ip>:8000 <--socket--> tcp://<redacted_internal_ip>:43347 <--Natter--> tcp://<redacted_external_ip>:43347
2026-03-11 12:42:01 [I]
2026-03-11 12:42:01 [I] LAN > <redacted_internal_ip>:8000   [ OPEN ]
2026-03-11 12:42:01 [I] LAN > <redacted_internal_ip>:43347  [ OPEN ]
2026-03-11 12:42:02 [I] LAN > <redacted_external_ip>:43347  [ CLOSED ]
2026-03-11 12:42:12 [I] WAN > <redacted_external_ip>:43347  [ UNKNOWN ]
2026-03-11 12:42:12 [I]

P.s: catatonit is there to allow PID1 process reaping.