feat: allow connection URI and add additional config parameters

[iwpnd]

Hi 👋

Now with the new pgx it is easier to pass a connection string which was on the wishlist for some issues (eg. #774). If the uri is set in the config.toml said uri is used without compromise as long as the basic information user, password, host, port and database are set. The sslmode is added if not specifically set.

Something on my personal wish list was the addition of "max_connection_idle_time" and "max_connection_lifetime" to the config that default to the pgx default if not specifically set.

[iwpnd]

woops. url.Values.Has() was only added with 1.17 - will fix

[coveralls]

Pull Request Test Coverage Report for Build c579f3eb8-PR-841

• 113 of 125 (90.4%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.4%) to 45.53%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
provider/postgis/error.go	6	11	54.55%
provider/postgis/postgis.go	107	114	93.86%

Files with Coverage Reduction	New Missed Lines	%
provider/postgis/postgis.go	2	61.91%

Totals
Change from base Build 905eed645:	0.4%
Covered Lines:	5577
Relevant Lines:	12249

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💛 - Coveralls

[iwpnd]

Thank you very much for the detailed review, @gdey. I’ll read up on error handling some more and fix the issues. 🙏🏻

[ARolek]

Overall this LGTM! I think we should deprecate the old config strategy in favor of the connection URI string. We should do this over 2 releases, so we should add a warning during the parsing step now.

[gdey]

LGTM

[ARolek]

One minot comment, but LGTM! Thank you for the contribution!

[durkie]

is there an example way to connect to a local postgresql database via UNIX socket connection with the new uri= scheme? I'm trying loads of different permutations but keep getting errors about missing user credentials or missing port.

[iwpnd]

I think you have to escape it or use host as Param. Never tried it myself tho.

postgresql:///dbname?host=/var/lib/postgresql

postgresql://%2Fvar%2Flib%2Fpostgresql/dbname

[durkie]

Yeah I haven't had much luck with either of those formats: escaping it with %2F results in parse errors, and not escaping it says "missing port". Adding a "port" via something like /var/lib/postgresql:5432 or ?port=5432 doesn't seem to work

[iwpnd]

Im sorry, can't help right now. Tegola is using pgx under the hood, maybe dig a little if that is an issue with pgx.

[durkie]

Sure thing. After digging around a bit, it looks like the main issue is using url.Parse to validate the postgresql connection string, and it chokes on finding a unix pathname. But that was helpful to dig around, and I found something that works:

uri = "postgresql://tegola:xxxx@127.0.0.1:5432/db_name?host=/run/postgresql&sslmode=disable"

• you have to provide both a valid URL and then the socket as a host= parameter.
• provides a dummy URL to connect to: the port 5432 in 127.0.0.1:5432 is important, because it uses this to discover the unix socket at /run/postgresql/.s.PGSQL.5432. The address doesn't seem to matter.
• sslmode=disable is necessary because otherwise you'll get TLS termination errors

[ARolek]

@durkie thanks for digging into this. Would be great to get some better error handling on these connection params. I would happily accept a PR if you feel so inclined. ;-)