Docker entrypoint and cmd together

Question

I try to setup a Docker with both entrypoint and cmd.

FROM debian:stretch
RUN apt-get update && \
apt install gnupg ca-certificates -y 
RUN echo "deb http://repo.aptly.info/ squeeze main" > /etc/apt/sources.list.d/aptly.list
RUN apt-key adv --keyserver keys.gnupg.net --recv-keys 9E3E53F19C7DE460
RUN apt update && apt install aptly -y
ADD aptly.conf /etc/aptly.conf
ADD start.sh .
VOLUME ["/aptly"]
ENTRYPOINT ["/start.sh"]
CMD ["aptly", "api", "serve"]

But entrypoint script is not stopping... The cmd command is not launching

Here my script :

#!/bin/bash
 set -e 
 init_aptly() { 
 #import pgp key
#create nginx root folder in /aptly
su -c "mkdir -p /aptly/.aptly/public"
echo "12"
 #initialize repository
 #aptly create repo doze-server -   distribution="stable"
  }
  #check for first run
 if [ ! -e /aptly/.aptly/public ]; then
  init_aptly
  echo "13"
 fi
  echo "14"

The script always echo 14, I would like only one and then, execute the cmd command from dockerfile

Solution 1

When you use both entrypoint and command, the command section will be appended to entrypoint executable as arguments. Thus in your case:

ENTRYPOINT ["/start.sh"]
CMD ["aptly", "api", "serve"]

Is equivalent to running:

ENTRYPOINT["/start.sh", "aptly", "api", "serve"]

Solution 2

Can't tell much without knowing what the entrypoint does, but essentially this is what you are doing with this combination of entrypoint and cmd:

/start.sh aptly api serve

If you are after simply starting your server you can simply do something like this (valid path to the aptly executable may be neccessary):

ENTRYPOINT ["aptly"]
CMD ["api", "serve"]

Unless you are doing much more than just running an executable there's no need for an entrypoint.

Solution 3

One important note, since nobody else has mentioned it: in order to use ENTRYPOINT and CMD together, you need to specify both in the array format. Doing something like this WILL NOT WORK:

ENTRYPOINT ./my_script.sh
CMD echo "hello world"

In the code above, ./my_script.sh will be called, but CMD will not be passed in.

Comments

[Vana]

No need cmd, just ENTRYPOINT [/start.sh aptly api serve]?

[emix]

Sorry I don't understand your question.

[yamenk]

You can combine executable like bash scripts CMD ./start.sh && aptly api serve

[George Pligoropoulos]

This is so intuitive of course.... Strong negative feelings for whoever dev implemented it like so!

[rj487]

This ans saved me even in 2019

[xnervwang]

Weird... behavior?

[benjaminchanming]

Thanks, you saved me from hours of debugging!

[ADJenks]

I must be blind but I couldn't seem to see where in the documentation it explains this. Can someone please put a link to the docs showing this?