Graphite formatted metric with -1 timestamp

[jenmud]

Describe the bug
When inserting a graphite metric using the Graphite message format metric_path value timestamp and the timestamp is -1, the row is skipped and with the following error message in the logs

2020-07-08T08:35:04.507Z        error   VictoriaMetrics/lib/storage/storage.go:1155     warn occurred during rows addition: cannot insert row with too small timestamp -1000 outside the retention; minimum allowed timestamp is 1591518903000

This behavior does not conform to the graphite spec outlined here where is states that if the timestamp is -1 it will use the time of arrival.

To Reproduce
Send a graphite metric with a -1 timestamp

echo "foo.bar.baz;tag1=value1;tag2=value2 123 -1" | nc -N localhost 2003

Expected behavior
Metric should be inserted into the data with the timestamp when the message arrived and processed by the database.

Screenshots
If applicable, add screenshots to help explain your problem.

Version

$ ./victoria-metrics-prod --version
victoria-metrics-20200701-115333-tags-v1.37.4-0-g8da3f773a

[valyala]

@jenmud , thanks for the bug report. It should be fixed in the commit eb45185 . This commit will be included in the next release. In the mean time you may build VictoriaMetrics from this commit according to these instructions.

There are the following workarounds for the bug:

• VictoriaMetrics accepts 0 timestamp in Graphite protocol and translates it to the current timestamp.
• VictoriaMetrics accepts Graphite lines without timestamp, i.e. foo 123 is translated to a foo metric with 123 value and with the current timestamp.

[valyala]

@jenmud , VictoriaMetrics should properly handle -1 timestamp in Graphite plaintext protocol starting from v1.38.0. Closing the issue as fixed.