confluent-hub install through proxy

I’m trying to run docker-compose up -d --build according to documentation but the process gets stuck on building step:

Step 5/5 : RUN confluent-hub install --no-prompt confluentinc/kafka-connect-datagen:latest
 ---> Running in c4b8de698b86
Running in a "--no-prompt" mode
java.net.ConnectException: Connection timed out (Connection timed out)

Server that I’m running docker on doesn’t have direct Internet access and configured to use proxy server so I tried to add environment variables to Dockerfile:

ENV HTTP_PROXY="my_proxy"
ENV HTTPS_PROXY="my_proxy"

But it doesn’t help.

I’ve pulled confluentinc/cp-kafka-connect:5.2.1 docker image, run it interactively and tried to install kafka-connect-datagen:latest manually

docker pull confluentinc/cp-kafka-connect:5.2.1
docker run -it --rm confluentinc/cp-kafka-connect:5.2.1 /bin/bash
export http_proxy=MY_PROXY_ADDRESS
export https_proxy=MY_PROXY_ADDRESS
confluent-hub install --no-prompt confluentinc/kafka-connect-datagen:latest

But the image still cannot be downloaded.

curl -I https://api.hub.confluent.io/api/plugins says that connection was successful so obviously there is no proxy support for confluent-hub client. Is there any workaround for this issue?

[z3rohour]

As usual, I managed to fix the problem by myself right after posting 😃 Proxy parameters are taken from zulu-8-amd64 package so I simply add few lines into Dockerfile which define default proxy settings for Java:

RUN sed -i 's/# http.proxyHost=/http.proxyHost=MY_PROXY_ADDRESS/g' /usr/lib/jvm/zulu-8-amd64/jre/lib/net.properties && \
    sed -i 's/# http.proxyPort=80/http.proxyPort=MY_PROXY_PORT/g' /usr/lib/jvm/zulu-8-amd64/jre/lib/net.properties && \
    sed -i 's/# https.proxyHost=/https.proxyHost=MY_PROXY_ADDRESS/g' /usr/lib/jvm/zulu-8-amd64/jre/lib/net.properties && \
    sed -i 's/# https.proxyPort=443/https.proxyPort=MY_PROXY_PORT/g' /usr/lib/jvm/zulu-8-amd64/jre/lib/net.properties && \
    confluent-hub install --no-prompt confluentinc/kafka-connect-datagen:latest

[vielfarbig]

I use the image confluentinc/ksqldb-server:0.17.0 and installation via confluent-hub install in the docker-compose command option, as you can see in https://github.com/confluentinc/demo-scene/blob/master/ksqldb-tombstones/docker-compose.yml. In this version zulu11 is used and you have to edit /usr/lib/jvm/zulu11/conf/net.properties. This cannot be edited by the docker-compose command option, because the user has not enough permissons. So I copied the net.properties with docker cp ksqldb:/usr/lib/jvm/zulu11/conf/net.properties ., edited and mounted the net.properties by:

    volumes:
      - ./net.properties:/usr/lib/jvm/zulu11/conf/net.properties

In the net.properties it is important to not use the schema, so http:// before the hosts, as so:

http.proxyHost=proxy.example.com
http.proxyPort=80
http.nonProxyHosts=localhost|127.*|[::1]

https.proxyHost=proxy.example.com
https.proxyPort=443