CI Jenkinsfile: change rotation and deletion of previous workspaces

Recantly added workspace rename did not happen if build failed,
causing longer duration in next clean stage, but what's worse,
failed workspace was not preserved, contrary to what we need.
Moving rename operation to finally block would add race possibilities.
So we change the workspaces naming scheme. Workspace gets name
with CI_BUILD_ID from very start, thus eliminating need
to rename and risk of race. Older workspaces get deleted
as CI_BUILD_ID ensures ordered-in-time series.
Use regex in deletion and separate pass for temp.dirs.
Workspace name prefix is shortened to ci- for shorter path names.

Signed-off-by: Olev Kartau <olev.kartau@intel.com>

Author: okartau

Jenkinsfile

@@ -28,7 +28,7 @@ def global_sum_log = ""
 def added_commits = ""
 def builder_node = ""
 def builder_wspace = ""
-def slot_name = "builder-slot-"
+def slot_name = "ci-"
 // reasonable value: keep few recent, dont take risk to fill disk
 int num_build_dirs_to_keep = 4
 
@@ -48,7 +48,7 @@ def script_env = """
 try {
     timestamps {
         node('rk-docker') {
-            ws("workspace/${slot_name}${env.EXECUTOR_NUMBER}") {
+            ws("workspace/${slot_name}${ci_build_id}") {
                 // remember node and workspace needed by workspace cleaner
                 builder_node = "${env.NODE_NAME}"
                 builder_wspace = "${env.WORKSPACE}"
@@ -102,11 +102,6 @@ try {
                     added_commits = readFile("added_commits")
                 }
             } // ws
-            // rotate workspace out of way, rename using CI_BUILD_ID.
-            // Older trees are deleted later in test_runs[], without keeping build waiting.
-            ws("workspace") {
-                sh "mv ${builder_wspace} ${builder_wspace}.ci-prev.${ci_build_id}"
-            }
         } // node
     } // timestamps
 
@@ -301,12 +296,17 @@ def step_xunit() {
 }
 
 // Delete older builder trees.
-// While majority/regular workspaces are named builder-slot-0, (for EXECUTOR=0),
-// Jenkins may create additional trees as builder-slot-0_X.
-// Wildcard covers all such workspaces, dont want some pattern filling disk independently.
+// While majority/regular workspaces are named ci-CI_BUILD_ID,
+// Jenkins may create additional trees as ci-build-CI_BUILD_ID_<NUM>
+// Regex with underscore should cover all such workspaces.
 def trim_build_dirs(slotname, num_to_keep) {
     sh """
-dirs=`find ${env.WORKSPACE} -mindepth 1 -maxdepth 1 -type d -name "${slotname}*.ci-prev.*" |sort -n |head -n -${num_to_keep} |tr '\n' ' '`
+# tmpdirs in separate pass
+dirs=`find . -mindepth 1 -maxdepth 1 -type d -regex ".*/${slotname}[0-9_-]*-build-[0-9_]*.*tmp\$" |sort -n |head -n -${num_to_keep} |tr '\n' ' '`
+if [ -n "\${dirs}" ]; then
+    ionice -c 3 rm -fr \$dirs
+fi
+dirs=`find . -mindepth 1 -maxdepth 1 -type d -regex ".*/${slotname}[0-9_-]*-build-[0-9_]*\$" |sort -n |head -n -${num_to_keep} |tr '\n' ' '`
 if [ -n "\${dirs}" ]; then
     ionice -c 3 rm -fr \$dirs
 fi