Relevant telegraf.conf:

[[inputs.postgresql]]
address = ""

System info:

• Telegraf at commit 36193aea
• postgresql version 10.5-0ubuntu0.18.04

Steps to reproduce:

• set an empty address in telegraf.conf for that DB

Expected behavior:

• DB connection should use the PostgreSQL default, which is the use of a local unix domain socket

Actual behavior:

• The DB connection uses a TCP connection via localhost and disables SSL

Additional info:

This issue is a fairly low priority, but it got me stumped when playing around with telegraf. On my development box I don't need TCP connections to PostgreSQL and never enabled it. All my apps run locally using a unix-domain socket. This is the default config of PostgreSQL. All other PG clients I know of (including psql) will connect using the Unix domain socket when no DSN is specified.

I would expect telegraf to behave like any other PG client in it's default config.

Right now the DSN is hardcoded to localhost if an empty address is specified.