Re: Openmetrics label truncation

On 03/06/2022 11:13 Daniel Sabotta wrote:

Hello,

I'm using dovecot 2.3.18 and want to collect metrics with prometheus via openmetrics.

I need to label the metrics with the destination host name. The configuration works fine, but the label value is truncated after 32 chars (and a '...' is added).

My config:

service stats { inet_listener http { port = 9323 } }

metric my_metric { filter = event=smtp_client_transaction_finished group_by = dest_host status_code }

I wrote a simple patch, that fixes that for me:

diff --git a/src/stats/stats-metrics.c b/src/stats/stats-metrics.c index 877c142546..30126563ff 100644 --- a/src/stats/stats-metrics.c +++ b/src/stats/stats-metrics.c @@ -357,7 +357,7 @@ stats_metric_sub_metric_alloc(struct metric *metric, const char *name, pool_t po array_append_zero(&fields); sub_metric = stats_metric_alloc(pool, metric->name, metric->set, array_idx(&fields, 0)); - sub_metric->sub_name = p_strdup(pool, str_sanitize_utf8(name, 32)); + sub_metric->sub_name = p_strdup(pool, str_sanitize_utf8(name, 63)); array_append(&metric->sub_metrics, &sub_metric, 1); return sub_metric; }

Why are labels truncated after 32? Is there a reason I do not see? I found no reasons in the openmetrics specification [1].

Thanks in advance

Daniel

Can you epxlain us the usecase where you need such long labels? Aki Tuomi