[pve-devel] [PATCH container v3] fix #3815: influxdb vmname should be string

[Markus Frank <m.frank@proxmox.com>]

InfluxDB interprets the vmname 66601 as a number and the vmname vm42 as a String.
This leads to problematic metrics, that will be dropped by influxdb.
Whichever comes first decides how the "schema" is defined.

To change that I added a $to_quote hashmap to define which value
shouldn't get interpreted as number.
In this case the value of name.

Change: Conversion happends in prepare_value.

nodename and host are tags in InfluxDB so the only value they are able
to contain are strings:
https://docs.influxdata.com/influxdb/v2.1/reference/syntax/line-protocol/

Signed-off-by: Markus Frank <m.frank@proxmox.com>
---
 PVE/Status/InfluxDB.pm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/PVE/Status/InfluxDB.pm b/PVE/Status/InfluxDB.pm
index def7e2fd..63a865df 100644
--- a/PVE/Status/InfluxDB.pm
+++ b/PVE/Status/InfluxDB.pm
@@ -276,6 +276,8 @@ sub test_connection {
 sub build_influxdb_payload {
     my ($class, $txn, $data, $ctime, $tags, $excluded, $measurement, $instance) = @_;
 
+    # 'abc' and '123' are both valid hostnames, that confuses influx's type detection
+    my $to_quote = { name => 1 };
     my @values = ();
 
     foreach my $key (sort keys %$data) {
@@ -286,7 +288,7 @@ sub build_influxdb_payload {
 	if (!ref($value) && $value ne '') {
 	    # value is scalar
 
-	    if (defined(my $v = prepare_value($value))) {
+	    if (defined(my $v = prepare_value($value, $to_quote->{$key}))) {
 		push @values, "$key=$v";
 	    }
 	} elsif (ref($value) eq 'HASH') {
@@ -331,9 +333,10 @@ sub get_recursive_values {
 }
 
 sub prepare_value {
-    my ($value) = @_;
+    my ($value, $quote) = @_;
 
-    if (looks_like_number($value)) {
+    # don't treat value like a number if quote is 1
+    if (looks_like_number($value) && !$quote) {
 	if (isnan($value) || isinf($value)) {
 	    # we cannot send influxdb NaN or Inf
 	    return undef;
-- 
2.30.2