[PATCH v2 1/1] add uuid to schroot folder instead of pid

[Felix Moessbauer <felix.moessbauer@siemens.com>]

PIDs are not unique across containers.
When running the build in a container (e.g. the kas container),
the PID of bitbake is likely the same across multiple simultaneously
running builds.

This is especially the case for CI runners, where it is common that
multiple jobs run in parallel.

This patch replaces the PID component by a random UUID that is injected
from the ISAR environment.

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 meta/classes/sbuild.bbclass    | 2 +-
 meta/conf/bitbake.conf         | 7 ++++++-
 scripts/isar-buildenv-internal | 4 +++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/meta/classes/sbuild.bbclass b/meta/classes/sbuild.bbclass
index f9bfaaf6..03917533 100644
--- a/meta/classes/sbuild.bbclass
+++ b/meta/classes/sbuild.bbclass
@@ -23,7 +23,7 @@ python __anonymous() {
     d.setVar('SCHROOT_DEP', dep)
 }
 
-SBUILD_CHROOT ?= "${DEBDISTRONAME}-${SCHROOT_USER}-${@os.getpid()}"
+SBUILD_CHROOT ?= "${DEBDISTRONAME}-${SCHROOT_USER}-${PN}-${ISAR_BUILD_UUID}"
 
 SBUILD_CONF_DIR ?= "${SCHROOT_CONF}/${SBUILD_CHROOT}"
 SCHROOT_CONF_FILE ?= "${SCHROOT_CONF}/chroot.d/${SBUILD_CHROOT}"
diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 6451cb59..31e11569 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -104,7 +104,7 @@ BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH BBSERVER DL_DI
     WORKDIR STAMPCLEAN PKGDATA_DIR BUILD_ARCH SSTATE_PKGARCH \
     BB_WORKERCONTEXT BB_LIMITEDDEPS DEPLOY_DIR BUILDCHROOT_DIR \
     REPO_ISAR_DIR REPO_ISAR_DB_DIR REPO_BASE_DIR REPO_BASE_DB_DIR LAYERDIR_core \
-    SCRIPTSDIR TOPDIR"
+    SCRIPTSDIR TOPDIR ISAR_BUILD_UUID"
 BB_HASHCONFIG_WHITELIST ?= "${BB_HASHBASE_WHITELIST} DATE TIME SSH_AGENT_PID \
     SSH_AUTH_SOCK PSEUDO_BUILD BB_ENV_EXTRAWHITE DISABLE_SANITY_CHECKS \
     BB_NUMBER_THREADS BB_ORIGENV BB_INVALIDCONF BBINCLUDED \
@@ -134,6 +134,11 @@ USE_CCACHE ??= "0"
 CCACHE_TOP_DIR ?= "${TMPDIR}/ccache"
 CCACHE_DIR ?= "${CCACHE_TOP_DIR}/${DISTRO}-${DISTRO_ARCH}"
 
+# Unique ID for this build, used to avoid name clashes on external mountpoints
+# When running parallel builds in different PID namespaces, overwrite
+# this with a globally unique value (e.g. by injecting a UUID from the environment)
+ISAR_BUILD_UUID ??= "none"
+
 include conf/local.conf
 include conf/multiconfig/${BB_CURRENT_MC}.conf
 include conf/machine/${MACHINE}.conf
diff --git a/scripts/isar-buildenv-internal b/scripts/isar-buildenv-internal
index ec8e4377..e5cb5364 100755
--- a/scripts/isar-buildenv-internal
+++ b/scripts/isar-buildenv-internal
@@ -62,6 +62,8 @@ export BUILDDIR
 export BITBAKEDIR="${ISARROOT}/bitbake"
 export SCRIPTSDIR="${ISARROOT}/scripts"
 export TESTSUITEDIR="${ISARROOT}/testsuite"
+# use builtin python uuid to avoid dep to uuidgen
+export ISAR_BUILD_UUID="$(python3 -c 'import uuid; print(str(uuid.uuid4()))')"
 
 for newpath in "$BITBAKEDIR/bin" "$SCRIPTSDIR"; do
     # Remove any existences of $newpath from $PATH
@@ -77,5 +79,5 @@ export PATH
 BBPATH="${BUILDDIR}"
 export BBPATH
 
-BB_ENV_EXTRAWHITE="BITBAKEDIR SCRIPTSDIR TESTSUITEDIR http_proxy https_proxy ftp_proxy no_proxy GNUPGHOME"
+BB_ENV_EXTRAWHITE="BITBAKEDIR SCRIPTSDIR TESTSUITEDIR http_proxy https_proxy ftp_proxy no_proxy GNUPGHOME ISAR_BUILD_UUID"
 export BB_ENV_EXTRAWHITE
-- 
2.30.2