[Rkt](https://coreos.com/rkt) doesn't allow ports to be exposed to containers unless they are declared in the container manifest. Re-adding EXPOSE back in (removed in fa3a0f8bc8) allows the container to be used on rkt based systems.
- Always run apt update before any other apt command. (This fixes
incremental builds failing if a remote package is updated.)
- Only copy dependency lists before installing dependencies. (This means
editing code doesn't force all dependencies to be re-downloaded.)
- Delete cache in the same layer that it is created. (Otherwise,
deleting cache *increases* the size of the image on non-squashed
builds.)
- Move the installation of some static dependencies to *before* Mastodon
code is imported to Docker.
https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-4-4-released/
> This release includes some bug fixes and some security fixes.
>
> - CVE-2017-17742: HTTP response splitting in WEBrick
> - CVE-2018-6914: Unintentional file and directory creation with directory traversal in tempfile and tmpdir
> - CVE-2018-8777: DoS by large request in WEBrick
> - CVE-2018-8778: Buffer under-read in String#unpack
> - CVE-2018-8779: Unintentional socket creation by poisoned NUL byte in UNIXServer and UNIXSocket
> - CVE-2018-8780: Unintentional directory traversal by poisoned NUL byte in Dir
> - Multiple vulnerabilities in RubyGems
Both of yarn and npm are used in Mastodon, but the combined usage requires
a redundant dependency and may lead to data inconsistency.
Considering that yarn has autoclean feature which npm does not have,
this change replaces all npm usage with yarn.
This change requires documentation update. Most notably, the following
command must be executed before assets precompilation if any system
dependency of node-sass has changed:
yarn install --force --pure-lockfile
When volumes are declared, but the corresponding directories don't exist, permissions for those directories will be root:root instead of mastodon:mastodon..
This changes makes sure the permissions of the volume directories are as expected.
