alesharik/prometheus-fdw

Prometheus Foreign Data Wrapper

Postgres extension to fetch data from prometheus.

Setup

create extension prometheusfdw; -- load extension

create foreign data wrapper prometheus_wrapper
  handler prometheus_fdw_handler
  validator prometheus_fdw_validator; -- create FDW

create server test_server
  foreign data wrapper prometheus_wrapper
  options (
    address 'http://172.25.0.3:9090/' -- server address
  ); -- connect to prometheus server

create foreign table scrape_duration_seconds (
    __name__ text, -- column name is fetched from labels
    instance text,
    job text,
    value double precision -- or from sample value
)
  server test_server
  options (
    query 'scrape_duration_seconds' -- use this query to fetch data
  ); -- create table

Query format

Query can contain variables like ${var}. These will be replaced by values from where clause. If array of values is passed in ${var}, it will be wrapped with () and concatenated with |.

Where parameters

• time timestamp - when running instant query, specifies timestamp from where to take samples. Expects UTC.

Table parameters

• query - PromQL query
• rate - (optional) rate parameter for VictoriaMetrics

Todo

• Range queries