nix-super/tests/functional/local-overlay-store/common.sh
Valentin Gagarin 33ca905cdb tests: simplify initialisation and wiring
pararameterisation is not actually needed the way things are currently
set up, and it confused me when trying to understand what the code does.

all but one test sources vars-and-functions.sh, which nominally only
defines variables, but in practice is always coupled with the actual
initialisation. while the cleaner way of making this more legible would
be to source variables and initialisation separately, this would produce
a huge diff.

the change requires a few small fixes to keep the tests working:

- only create test home directory during initialisation

  that vars-and-functions.sh wrote to the file system seems not write

- fix creation of the test directory

  due to statefulness, the test home directory was implicitly creating
  the test root, too. decoupling that made it apparent that this was
  probably not intentional, and certainly confusing.

- only source vars-and-functions.sh if init.sh is not needed

  there is one test case that only needs a helper function but no
  initialisation side effects

- remove some unnecessary cleanups and split parts of re-used test code

  there were confusing bits in how initialisation code was repurposed,
  which break if trying to refactor the outer layers naively...
2024-05-13 15:19:49 +02:00

105 lines
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source ../common/vars-and-functions.sh
# The new Linux mount interface does not seem to support remounting
# OverlayFS mount points.
#
# It is not clear whether this is intentional or not:
#
# The kernel source code [1] would seem to indicate merely remounting
# while *changing* mount options is now an error because it erroneously
# succeeded (by ignoring those new options) before. However, we are
# *not* trying to remount with changed options, and are still hitting
# the failure when using the new interface.
#
# For further details, see these `util-linux` issues:
#
# - https://github.com/util-linux/util-linux/issues/2528
# - https://github.com/util-linux/util-linux/issues/2576
#
# In the meantime, setting this environment variable to "always" will
# force the use of the old mount interface, keeping the remounting
# working and these tests passing.
#
# [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/overlayfs/params.c?id=3006adf3be79cde4d14b1800b963b82b6e5572e0#n549
export LIBMOUNT_FORCE_MOUNT2=always
requireEnvironment () {
requireSandboxSupport
[[ $busybox =~ busybox ]] || skipTest "no busybox"
if [[ $(uname) != Linux ]]; then skipTest "Need Linux for overlayfs"; fi
needLocalStore "The test uses --store always so we would just be bypassing the daemon"
}
addConfig () {
echo "$1" >> "$NIX_CONF_DIR/nix.conf"
}
setupConfig () {
addConfig "require-drop-supplementary-groups = false"
addConfig "build-users-group = "
enableFeatures "local-overlay-store"
}
setupStoreDirs () {
# Attempt to create store dirs on tmpfs volume.
# This ensures lowerdir, upperdir and workdir will be on
# a consistent filesystem that fully supports OverlayFS.
storeVolume="$TEST_ROOT/stores"
mkdir -p "$storeVolume"
mount -t tmpfs tmpfs "$storeVolume" || true # But continue anyway if that fails.
storeA="$storeVolume/store-a"
storeBTop="$storeVolume/store-b"
storeBRoot="$storeVolume/merged-store"
storeB="local-overlay://?root=$storeBRoot&lower-store=$storeA&upper-layer=$storeBTop"
# Creating testing directories
mkdir -p "$storeVolume"/{store-a/nix/store,store-b,merged-store/nix/store,workdir}
}
# Mounting Overlay Store
mountOverlayfs () {
mount -t overlay overlay \
-o lowerdir="$storeA/nix/store" \
-o upperdir="$storeBTop" \
-o workdir="$storeVolume/workdir" \
"$storeBRoot/nix/store" \
|| skipTest "overlayfs is not supported"
cleanupOverlay () {
umount "$storeBRoot/nix/store"
rm -r $storeVolume/workdir
}
trap cleanupOverlay EXIT
}
remountOverlayfs () {
mount -o remount "$storeBRoot/nix/store"
}
toRealPath () {
storeDir=$1; shift
storePath=$1; shift
echo $storeDir$(echo $storePath | sed "s^${NIX_STORE_DIR:-/nix/store}^^")
}
initLowerStore () {
# Init lower store with some stuff
nix-store --store "$storeA" --add ../dummy
# Build something in lower store
drvPath=$(nix-instantiate --store $storeA ../hermetic.nix --arg withFinalRefs true --arg busybox "$busybox" --arg seed 1)
pathInLowerStore=$(nix-store --store "$storeA" --realise $drvPath)
}
execUnshare () {
exec unshare --mount --map-root-user "$SHELL" "$@"
}
addTextToStore() {
storeDir=$1; shift
filename=$1; shift
content=$1; shift
filePath="$TEST_HOME/$filename"
echo "$content" > "$filePath"
nix-store --store "$storeDir" --add "$filePath"
}