Merge pull request #49897 from mikedanese/atomic-append

Automatic merge from submit-queue (batch tested with PRs 49898, 49897, 49919, 48860, 49491) gce: make append_or_replace.. atomic Before this change, * the final echo is not atomically written to the target file * two concurrent callers will use the same tempfile Helps with https://github.com/kubernetes/kubernetes/issues/49895 cc @miekg

Merge pull request #49897 from mikedanese/atomic-append
49955b15 · Kubernetes Submit Queue · GitHub · d79c8fe4 · 1c2feb02 · 49955b15
Commit 49955b15 authored Aug 01, 2017 by Kubernetes Submit Queue Committed by GitHub Aug 01, 2017
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configure-helper.sh cluster/gce/gci/configure-helper.sh +5 -2

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--- a/cluster/gce/gci/configure-helper.sh
+++ b/cluster/gce/gci/configure-helper.sh
@@ -239,10 +239,13 @@ function append_or_replace_prefixed_line {
  local -r file="${1:-}"
  local -r prefix="${2:-}"
  local -r suffix="${3:-}"
+  local -r dirname="$(dirname ${file})"
+  local -r tmpfile="$(mktemp -t filtered.XXXX --tmpdir=${dirname})"
  touch "${file}"
-  awk "substr(\$0,0,length(\"${prefix}\")) != \"${prefix}\" { print }" "${file}" > "${file}.filtered"  && mv "${file}.filtered" "${file}"
+  awk "substr(\$0,0,length(\"${prefix}\")) != \"${prefix}\" { print }" "${file}" > "${tmpfile}"
-  echo "${prefix}${suffix}" >> "${file}"
+  echo "${prefix}${suffix}" >> "${tmpfile}"
+  mv "${tmpfile}" "${file}"
 }
 function create-node-pki {