[WIP] builtextend: produce a squashfs artifact

coreos-assembler

@@ -37,7 +37,7 @@ cmd=${1:-}
 # commands we'd expect to use in the local dev path
 build_commands="init fetch build run prune clean"
 # commands more likely to be used in a prod pipeline only
-advanced_build_commands="buildprep buildextend-ec2 buildextend-openstack oscontainer"
+advanced_build_commands="buildprep buildextend-ec2 buildextend-openstack buildextend-squashfs oscontainer"
 utility_commands="tag compress bump-timestamp"
 other_commands="shell"
 if [ -z "${cmd}" ]; then

src/cmd-buildextend-squashfs

@@ -0,0 +1,66 @@
+#!/usr/bin/python3 -u
+# An operation that mutates a build by generating a squashfs rootfs.
+
+import os
+import sys
+import json
+import yaml
+import shutil
+import argparse
+
+sys.path.insert(0, '/usr/lib/coreos-assembler')
+from cmdlib import run_supermin, run_verbose, write_json, sha256sum_file
+
+# Parse args and dispatch
+parser = argparse.ArgumentParser()
+parser.add_argument("--build", help="Build ID")
+args = parser.parse_args()
+
+# default to latest build if not specified
+if not args.build:
+    with open('builds/builds.json') as f:
+        j = json.load(f)
+        args.build = j['builds'][0]
+
+print(f"Targeting build: {args.build}")
+
+with open('src/config/manifest.yaml') as f:
+    manifest = yaml.safe_load(f)
+
+base_name = manifest['rojig']['name']
+img_prefix = f'{base_name}-{args.build}'
+artifact_name = f'{img_prefix}.rootfs.squashfs'
+
+builddir = f'builds/{args.build}'
+buildmeta_path = f'{builddir}/meta.json'
+with open(buildmeta_path) as f:
+    buildmeta = json.load(f)
+
+tmpdir = 'tmp/buildpost-squashfs'
+if os.path.isdir(tmpdir):
+    shutil.rmtree(tmpdir)
+os.mkdir(tmpdir)
+
+
+def generate_squashfs(workdir):
+    ref = buildmeta['ref']
+    tmp_img = f'{tmpdir}/{artifact_name}'
+    script = f'''#!/usr/bin/env bash
+set -xeuo pipefail
+ostree checkout --repo {workdir}/repo/ {ref} /tmp/rootfs
+/sbin/mksquashfs /tmp/rootfs {workdir}/{tmp_img}
+    '''
+
+    run_supermin(workdir, script)
+    checksum = sha256sum_file(tmp_img)
+    buildmeta['images']['squashfs'] = {
+        'path': artifact_name,
+        'sha256': checksum
+    }
+    os.rename(tmp_img, f"{builddir}/{artifact_name}")
+    write_json(buildmeta_path, buildmeta)
+    print(f"Updated: {buildmeta_path}")
+
+
+# Do it!
+generate_squashfs(os.getcwd())

src/cmdlib.py

@@ -2,12 +2,15 @@
 
 import hashlib
 import json
+import multiprocessing
 import os
+import shutil
 import subprocess
 import sys
 import tempfile
 from datetime import datetime
 
+libdir = '/usr/lib/coreos-assembler/'
 
 def run_verbose(args, **kwargs):
     print("+ {}".format(subprocess.list2cmdline(args)))
@@ -50,3 +53,82 @@ def rm_allow_noent(path):
         os.unlink(path)
     except FileNotFoundError:
         pass
+
+
+def run_supermin(workdir, script=''):
+    vmpreparedir = f"{workdir}/tmp/supermin.prepare"
+    if os.path.isdir(vmpreparedir):
+        shutil.rmtree(vmpreparedir)
+    os.makedirs(vmpreparedir, exist_ok=True)
+
+    vmbuilddir = f"{workdir}/tmp/supermin.build"
+    if os.path.isdir(vmbuilddir):
+        shutil.rmtree(vmbuilddir)
+    os.makedirs(vmbuilddir, exist_ok=True)
+
+    rpms = []
+    with open(f"{libdir}/vmdeps.txt") as vmdeps:
+        for line in vmdeps:
+            if not line or line.startswith('#'):
+                continue
+            for pkg in line.split():
+                rpms.append(pkg)
+
+    run_verbose(['supermin',
+                 '--prepare',
+                 '--use-installed',
+                 '-o', f"{vmpreparedir}"] + rpms)
+
+    with open(f"{libdir}/supermin-init-prelude.sh") as prelude:
+        sm_init = prelude.read()
+
+    with open(f"{workdir}/tmp/cmd.sh", "w+") as scriptfile:
+        scriptfile.write(script)
+    initscript = f'''#!/usr/bin/env bash
+set -xeuo pipefail
+workdir={workdir}
+{sm_init}
+RC=0
+sh {workdir}/tmp/cmd.sh || RC=$?
+echo $RC > {workdir}/tmp/rc
+/sbin/fstrim -v {workdir}/cache
+/sbin/poweroff -f
+    '''
+    with open(f"{vmpreparedir}/init", "w+") as vminit:
+        vminit.write(initscript)
+    os.chmod(f"{vmpreparedir}/init", 0o755)
+    run_verbose(['tar',
+                 '-C', f"{vmpreparedir}",
+                 '-czf', f"{vmpreparedir}/init.tar.gz",
+                 '--remove-files',
+                 'init'])
+
+    run_verbose(['supermin',
+                 '--build', f"{vmpreparedir}",
+                 '--size', '5G',
+                 '-f', 'ext2',
+                 '-o', f"{vmbuilddir}"])
+
+    nproc = multiprocessing.cpu_count()
+    run_verbose(['qemu-kvm', '-nodefaults', '-nographic', '-no-reboot',
+                 '-smp', f"{nproc}",
+                 '-m', '2048',
+                 '-kernel', f"{vmbuilddir}/kernel",
+                 '-initrd', f"{vmbuilddir}/initrd",
+                 '-netdev', 'user,id=eth0,hostname=supermin',
+                 '-device', 'virtio-net-pci,netdev=eth0',
+                 '-device', 'virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x3',
+                 '-drive', f"if=none,id=drive-scsi0-0-0-0,snapshot=on,file={vmbuilddir}/root",
+                 '-device', 'scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1',
+                 '-drive', f"if=none,id=drive-scsi0-0-0-1,discard=unmap,file={workdir}/cache/cache.qcow2",
+                 '-device', 'scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi0-0-0-1,id=scsi0-0-0-1',
+                 '-virtfs', f"local,id=workdir,path={workdir},security_model=none,mount_tag=workdir",
+                 '-serial', 'stdio', '-append', 'root=/dev/sda console=ttyS0 selinux=1 enforcing=0 autorelabel=1'])
+
+    rc = 99
+    with open(f"{workdir}/tmp/rc") as rcfile:
+        rc = int(rcfile.readline())
+
+    if rc != 0:
+        raise Exception(f"failed to run supermin (rc: {rc})")
+    return

src/deps.txt

@@ -28,7 +28,7 @@ libvirt libguestfs-tools qemu-kvm /usr/bin/qemu-img /usr/bin/virsh /usr/bin/virt
 rsync python2-gobject-base python3-gobject-base
 
 # To support recursive containerization and manipulating images
-podman buildah skopeo
+podman buildah skopeo squashfs-tools
 
 # Miscellaneous tools
 jq awscli

src/vmdeps.txt

@@ -6,6 +6,9 @@ bash vim-minimal coreutils util-linux procps-ng kmod kernel-modules
 # for composes
 rpm-ostree distribution-gpg-keys jq
 
+# for artifacts
+squashfs-tools
+
 # for clean reboot
 systemd