[RFC #0096] Lifecycle should detect Target OS from etc/os-release

[joe-kimmel-vmw]

Description

as part of the "stack removal" work we are adding the Target metadata, which is more specific information about the OS. Already through the work in #743 and #742 we pull this data from the Run Image OCI artifact metadata, however we can also pull it from the filesystem of the run image.

Proposed solution

According to the internet:

The /etc/os-release and /usr/lib/os-release files contain operating system identification data. The format of os-release is a newline-separated list of environment-like shell-compatible variable assignments.

Therefore in cases where there is no metadata from the RunImage available we should also try to infer from the filesystem. If the runImage has the metadata then we will not check the file system information.

Describe alternatives you've considered

Additional context

[joe-kimmel-vmw]

man os-release : https://www.freedesktop.org/software/systemd/man/os-release.html

[joe-kimmel-vmw]

three examples:

PRETTY_NAME="Debian GNU/Linux 10 (buster)"
NAME="Debian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

NAME="Ubuntu"
VERSION="18.04.3 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.3 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

NAME="Fedora Linux"
VERSION="37 (Cloud Edition)"
ID=fedora
VERSION_ID=37
VERSION_CODENAME=""
PLATFORM_ID="platform:f37"
PRETTY_NAME="Fedora Linux 37 (Cloud Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:37"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f37/system-administrators-guide/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=37
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=37
VARIANT="Cloud Edition"
VARIANT_ID=cloud

[robdimsdale]

Also, just for posterity, this is the contents of the jammy base stack's build image's /etc/os-release:

SUPPORT_URL="https://github.com/paketo-buildpacks/jammy-base-stack/blob/main/README.md"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
NAME="Ubuntu"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://github.com/paketo-buildpacks/jammy-base-stack"
BUG_REPORT_URL="https://github.com/paketo-buildpacks/jammy-base-stack/issues/new"
PRETTY_NAME="Paketo Buildpacks Base Jammy"
VERSION_ID="22.04"
VERSION="22.04.2 LTS (Jammy Jellyfish)"