Fixing out of memory using pack builder create on pack 0.30.0

[jjbustamante]

Summary

This PR replaces the uses of io.ReadAll() when processing a tarball file for io.Copy and avoid trying to load a huge file in memory

Output

Before

Running pack builder create with a buildpack containing a 4GB file on a host machine with limited memory (2GB) throws

Creating builder with the following buildpacks:
-> samples/java-maven@0.0.1
-> samples/kotlin-gradle@0.0.1
-> samples/ruby-bundler@0.0.1
-> memory-test@0.0.1
-> samples/hello-universe@0.0.1
-> samples/hello-moon@0.0.1
-> samples/hello-world@0.0.1
Killed

Status code: 137

After

The builder was created successfully

Documentation

• Should this change be documented?
  • Yes, see #___
  • No

Related

Resolves #1886