SOLR-16484 Remove gpg from image, slimming it down some Mb

[janhoy]

https://issues.apache.org/jira/browse/SOLR-16484

Small improvement to shave off some Mb

[janhoy]

I see that Dockerfile.body.template includes this line at the bottom:

    apt-get -y install acl dirmngr lsof procps wget netcat gosu tini jattach; \

...which installs both wget and dirmngr again. I see that a few of the scripts/ use wget, so it probably needs to stay (unless we can convert them to using curl), but why do we need dirmngr in the image runtime?

[dsmiley]

Shaving MB usually gets my approval :-)
(I have no clue RE dirmngr).

[janhoy]

Shaving MB usually gets my approval :-)

Sure. I hope we can use jlink in the future to shave off some JDK modules. The debian distro is already quite slim, but avoiding too many apt-get installs is important, they also drag in lib dependencies. However, removing less used jar dependencies from Solr is probably the main way to continue shaving. If only SolrCell could be a standalone project...

[dsmiley]

I think coming up with multiple tags would be how to slim further. solr:9-slim solr:9, solr:9-andTika, solr:9-prometheus
And also, continue Solr-package investments to make it easier to "install".

[HoustonPutman]

I think at some point it is very useful to have a tool inside the container, either wget or curl, that lets us debug issues with Solr.

[janhoy]

I think at some point it is very useful to have a tool inside the container, either wget or curl, that lets us debug issues with Solr.

Agree very much. Now we have both. wget weighs less than 1Mb so not worth the effort to convert all scripts to using cURL I think. But it could be done if one wanted.

[janhoy]

@HoustonPutman do you recall why we have dirmngr in the last RUN command? I think perhaps it is a leftover from when splitting Dockerfile into templates for local and prod. Then you moved the apt-get from top of the old Dockerfile to later in the body. I'm going to try to remove it ans run all integration tests...

[HoustonPutman]

Ahh didn't see your last change. But I don't remember off the top of my head. Probably test related, but I'm not confident.