pmlogger, libpcp: fix handling of dynamic instance domain labels

qa/1368.out

@@ -34,6 +34,24 @@ Metric Labels in the Log ...
         [0] name(2,3) : value(7,3) [instances]
     InDom 29.2[900] labels (11 bytes): {"bin":900}
         [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[100] labels (11 bytes): {"bin":100}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[200] labels (11 bytes): {"bin":200}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[300] labels (11 bytes): {"bin":300}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[400] labels (11 bytes): {"bin":400}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[500] labels (11 bytes): {"bin":500}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[600] labels (11 bytes): {"bin":600}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[700] labels (11 bytes): {"bin":700}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[800] labels (11 bytes): {"bin":800}
+        [0] name(2,3) : value(7,3) [instances]
+    InDom 29.2[900] labels (11 bytes): {"bin":900}
+        [0] name(2,3) : value(7,3) [instances]
 
 === Dump help text
 

qa/1747

@@ -0,0 +1,92 @@
+#!/bin/sh
+# PCP QA Test No. 1747
+# Exercise pmlogger labels handling for dynamic instance domains.
+#
+# Copyright (c) 2025 Red Hat.  All Rights Reserved.
+#
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+# get standard environment, filters and checks
+. ./common.product
+. ./common.filter
+. ./common.check
+
+[ -d $PCP_PMDAS_DIR/simple ] || _notrun "simple PMDA directory is not installed"
+
+_cleanup()
+{
+    cd $here
+    if $need_restore
+    then
+        need_restore=false
+        $sudo rm -rf $PCP_ETC_DIR/pcp/labels/*
+        _restore_config $PCP_ETC_DIR/pcp/labels
+        _restore_config $PCP_PMDAS_DIR/simple/simple.conf
+        _sighup_pmcd
+    fi
+    $sudo rm -rf $tmp $tmp.*
+}
+
+userid=`id -u`
+groupid=`id -g`
+hostname=`hostname`
+machineid=`_machine_id`
+domainname=`_domain_name`
+rm -f $seq_full
+
+status=0	# success is the default!
+need_restore=true
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_filter_labels()
+{
+    sed \
+        -e "s/.domainname.:.${domainname}./\"domainname\":\"DOMAIN\"/g" \
+        -e "s/.machineid.:.${machineid}./\"machineid\":\"MACHINE\"/g" \
+        -e "s/.hostname.:.${hostname}./\"hostname\":\"HOSTNAME\"/g" \
+        -e "s/.groupid.:$groupid/\"groupid\":GID/g" \
+        -e "s/.userid.:$userid/\"userid\":UID/g" \
+    #end
+}
+
+# real QA test starts here
+_save_config $PCP_ETC_DIR/pcp/labels
+$sudo rm -rf $PCP_ETC_DIR/pcp/labels/*
+_sighup_pmcd || _exit 1
+
+_save_config "$PCP_PMDAS_DIR/simple/simple.conf"
+conf="sec"
+echo $conf > "$tmp.simple.conf"
+$sudo cp "$tmp.simple.conf" "$PCP_PMDAS_DIR/simple/simple.conf"
+
+cat > $tmp.config <<EOF
+log mandatory on default { simple }
+EOF
+
+pmlogger -c $tmp.config -l $tmp.log -t 1sec -T 8sec $tmp.archive &
+pid=$!
+
+# delay for pmlogger startup
+pmsleep 0.5
+
+# inject changes to instances and labels
+for insts in "sec,min" "sec,min,hour"
+do
+    pmsleep 1.5
+    echo $insts > "$tmp.simple.conf"
+    $sudo cp "$tmp.simple.conf" "$PCP_PMDAS_DIR/simple/simple.conf"
+done
+
+# ensure pmlogger has completed (from use of the -T option)
+wait $pid
+cat $tmp.log | tee $seq_full | _filter_pmlogger_log
+
+# reading from the archive end, expect labels for three instances
+pmdumplog -ae $tmp.archive >> $seq_full
+#pminfo -fl simple.now >> $seq_full
+pminfo -l -O 6sec -a $tmp.archive simple.now | _filter_labels
+
+# success, all done
+exit

qa/1747.out

@@ -0,0 +1,16 @@
+QA output created by 1747
+Log for pmlogger on HOST started DATE
+
+[DATE] pmlogger(PID) Info: Start
+Config parsed
+Starting logger for host "HOST"
+Archive basename: ARCHIVE
+[DATE] pmlogger(PID) Info: pmlogger: End of run time, exiting
+
+Log finished DATE
+
+simple.now
+    labels {"domainname":"DOMAIN","groupid":GID,"hostname":"HOSTNAME","indom_name":"time","machineid":"MACHINE","role":"testing","unitsystem":"SI","userid":UID}
+    inst [0 or "sec"] labels {"domainname":"DOMAIN","groupid":GID,"hostname":"HOSTNAME","indom_name":"time","machineid":"MACHINE","role":"testing","units":"sec","unitsystem":"SI","userid":UID}
+    inst [1 or "min"] labels {"domainname":"DOMAIN","groupid":GID,"hostname":"HOSTNAME","indom_name":"time","machineid":"MACHINE","role":"testing","units":"min","unitsystem":"SI","userid":UID}
+    inst [2 or "hour"] labels {"domainname":"DOMAIN","groupid":GID,"hostname":"HOSTNAME","indom_name":"time","machineid":"MACHINE","role":"testing","units":"hour","unitsystem":"SI","userid":UID}

qa/group

@@ -2130,6 +2130,7 @@ pmcd.pdu
 1727 pmproxy libpcp_web pmda.openmetrics local
 1740 pmda.proc local
 1745 pmlogger libpcp pmval local pmda.sample pmda.simple pmlogdump
+1747 pmlogger labels local
 1748 atop local
 1753 fetch valgrind local
 1763 pmlogctl local

src/libpcp/src/logmeta.c

@@ -409,19 +409,24 @@ samelabelset(const pmLabelSet *set1, const pmLabelSet *set2)
 	if (n2 == set2->nlabels)
 	    return 0; /* not the same */
     }
-		
+
     /* All of the labels in set1 are in set2 with the same values. */
     return 1; /* the same */
 }
 
 /*
  * Discard any label sets within idp which are also within idp_next.
+ * Instance labels are a special case which cannot be reduced due to
+ * the potentially dynamic nature of the associated instance domain.
  */
 static void
 discard_dup_labelsets(__pmLogLabelSet *idp, const __pmLogLabelSet *idp_next)
 {
     int			i, j;
 
+    if (idp->type & PM_LABEL_INSTANCES)
+	return;
+
     for (i = 0; i < idp->nsets; ++i) {
 	for (j = 0; j < idp_next->nsets; ++j) {
 	    if (samelabelset(&idp->labelsets[i], &idp_next->labelsets[j])) {

src/pmlogger/src/callback.c

@@ -388,8 +388,14 @@ manageLabels(pmDesc *desc, const __pmTimestamp *tsp, int only_instances)
 	else
 	    ident = PM_IN_NULL;
 
-	/* Lookup returns >= 0 when the key exists */
-	if (__pmLogLookupLabel(&archctl, type, ident, &label, tsp) >= 0)
+	/*
+	 * Lookup returns >= 0 when the key exists
+	 *
+	 * In the instance-domain-is-changing scenario we can skip this
+	 * as we must always log label metadata in that special case.
+	 */
+	if (!only_instances &&
+	    __pmLogLookupLabel(&archctl, type, ident, &label, tsp) >= 0)
 	    continue;
 
 	if ((sts = putlabels(type, ident, tsp)) < 0)