From 5bc9e87da1165692562eecb3b4ffd698bf7f1ce7 Mon Sep 17 00:00:00 2001
From: Ian Wienand <iwienand@redhat.com>
Date: Tue, 26 Apr 2022 17:22:46 +1000
Subject: [PATCH] centos: avoid head pipe failure

I just saw in the trace output of a failure

  > grep -o 'CentOS-.[^>]*GenericCloud-.[^>]*.qcow2'
  > sort -r
  > head -1
  sort: fflush failed: 'standard output': Broken pipe
  sort: write error

i.e. the "head -1" has exited after reading one line, but "sort -r"
still wants to write and thus has hit a pipe failure, and because we
run with "-o pipefail" this has halted the script.

This seems like it has been there more or less forever, maybe we just
got lucky hitting it now?  Anyway, we can work around this by using a
process substitution and passing the output of this into head, this
way we won't hit a pipe failure.

I also updated the fedora path as it does the same thing.

Change-Id: I44d97e5bb31702aacf396e0229329a2ef9c64f2f
---
 diskimage_builder/elements/centos/root.d/10-centos-cloud-image | 2 +-
 diskimage_builder/elements/fedora/root.d/10-fedora-cloud-image | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/diskimage_builder/elements/centos/root.d/10-centos-cloud-image b/diskimage_builder/elements/centos/root.d/10-centos-cloud-image
index de79e4d9..d2529046 100755
--- a/diskimage_builder/elements/centos/root.d/10-centos-cloud-image
+++ b/diskimage_builder/elements/centos/root.d/10-centos-cloud-image
@@ -61,7 +61,7 @@ else
         else
             dib_release_path=${DIB_RELEASE}
         fi
-        BASE_IMAGE_FILE=${BASE_IMAGE_FILE:-$(curl -s https://cloud.centos.org/centos/${dib_release_path}/${ARCH}/images/ | grep -o "CentOS-.[^>]*${DIB_FLAVOR}-.[^>]*.qcow2" | sort -r | head -1)}
+        BASE_IMAGE_FILE=${BASE_IMAGE_FILE:-$(head -1 < <(curl -s https://cloud.centos.org/centos/${dib_release_path}/${ARCH}/images/ | grep -o "CentOS-.[^>]*${DIB_FLAVOR}-.[^>]*.qcow2" | sort -r))}
     fi
     BASE_IMAGE_TAR=$BASE_IMAGE_FILE.tgz
     IMAGE_LOCATION=$DIB_CLOUD_IMAGES/$BASE_IMAGE_FILE
diff --git a/diskimage_builder/elements/fedora/root.d/10-fedora-cloud-image b/diskimage_builder/elements/fedora/root.d/10-fedora-cloud-image
index 38793674..f3eb7bb1 100755
--- a/diskimage_builder/elements/fedora/root.d/10-fedora-cloud-image
+++ b/diskimage_builder/elements/fedora/root.d/10-fedora-cloud-image
@@ -44,7 +44,7 @@ else
         exit 1
         ;;
     esac
-    SUBRELEASE=$(curl -Ls $DIB_CLOUD_IMAGES/ | grep -o -P '(?<=Fedora-Cloud-Base-'${DIB_RELEASE}'-).*?(?=.'${ARCH}'.qcow2")' | sort -r | head -1)
+    SUBRELEASE=$(head -1 < <(curl -Ls $DIB_CLOUD_IMAGES/ | grep -o -P '(?<=Fedora-Cloud-Base-'${DIB_RELEASE}'-).*?(?=.'${ARCH}'.qcow2")' | sort -r))
     BASE_IMAGE_FILE=${BASE_IMAGE_FILE:-Fedora-Cloud-Base-$DIB_RELEASE-$SUBRELEASE.$ARCH.qcow2}
     BASE_IMAGE_TAR=Fedora-Cloud-Base-$DIB_RELEASE-$SUBRELEASE.$ARCH.tgz
     IMAGE_LOCATION=$DIB_CLOUD_IMAGES/$BASE_IMAGE_FILE