URLs in configuration file

[glebsts]

Hello,
Problem
Going through the pain of Clair v2->v4 upgrade.
Combo mode, single node, k8s deployment+service

I saw that I have to define http_listen_addr, A string in <host>:<port> in config.

And then I saw IndexerAddr and MatcherAddr both commented as A string in <host>:<port> format.

So I was quite happy about that, as I run Clair on single node, so I used YAML anchor functionality to have Clair address (and pgconn str) be defined once in the beginning of my config:

http_listen_addr: &clair_default_listener "0.0.0.0:6060"
introspection_addr: "0.0.0.0:6061"
//...
matcher:
  connstring: *clair_pg_connstr
  indexer_addr: *clair_default_listener

As Clair address is also appearing in matcher.indexer_addr, notifier.indexer_addr and notifier.matcher_addr, I was glad I don't need to duplicate it 4 times, because DRY!

But looks like docs are lying, as container started and I got
service initialization failed: failed to initialize notifier: parse \"0.0.0.0:6060\": first path segment in URL cannot contain colon error.
Turned out, Notifier config validation uses url.Parse() which is sensitive about missing schema, and docs said <host>:<port> should be sufficient.
So I changed my listener address to be http://0.0.0.0:6060, and then I got container failing immediately with error failed to validate config: address http://0.0.0.0:6060: too many colons in address, because (here docs don't lie) main Clair config validation uses net.SplitHostPort() which explicitly wants <host>:<port>.

As YAML anchors do not allow string concatenation, I have to put same 0.0.0.0:6060 twice, with and without http:// prefix.

Idea:

• to keep Clair config more DRY, use aligned approach for defining and parsing http_listen_addr and indexer_addr, matcher_addr
  • either use same parser
  • or add some TrimPrefix-like functionality
• update documentation