Switch to pigz to support multi-core tar command

[windhamwong]

pigz is a multi-core version of tar, which makes the docker build process much faster.

[nicknezis]

I'm not familiar with pigz. Is the resulting artifact equivalent to a gzip artifact? Does a user need pigz installed to tar -xzf the resulting files? Does that command even still work?

[Code0x58]

A couple of tests to show equivalence for consumers:
With gzip:

$ cat txt 
oink
$ ls
txt
$ pigz txt
$ ls
txt.gz
$ gunzip txt.gz 
$ ls
txt
$ cat txt 
oink

With tar:

$ tar --remove-files --use-compress-program=pigz -cf out.tar.gz txt
$ ls
out.tar.gz
$ tar -zxf out.tar.gz
$ cat txt
oink

[windhamwong]

https://zlib.net/pigz/
It is gzip format but with the parallel multi-core feature. The traditional gzip command uses only one core but modern CPU/vCPU has more than one.

[nicknezis]

1. Have all containers been tested? Do some of them need pigz included in their Dockerfiles?
2. Should bazel_configure.py be updated to check for pigz if it is an external dependency?
3. Do any of the website pages need to be updated? For instance brew install pigz for someone compiling on their Mac.

[windhamwong]

let me try out all docker builds tomorrow.

[windhamwong]

Docker build testing result:
ubuntu18.04 - success
ubuntu20.04 - success
ubuntu16.04 - success
debian9 - fail - python3.6 not supported (unrelated to pigz)
debian10 - fail - protobuf issue (unrelated to pigz)
centos7 - success