fix(knex): connection attrs missing if connectionString used

[edosrecki]

Which problem is this PR solving?

• Connection related attributes (hostname, port, user, database) are missing if users use connectionString property when initializing knex (instead of specifying individual fields):

const pg = require('knex')({
  client: 'pg',
  connection: {
    connectionString: config.DATABASE_URL,
  },
});

• Span name is also affected, for example here database = undefined:

Short description of the changes

• If connectionString is provided in knex options, extract attributes from it (hostname, port, user, database).
• If both connectionString and individual fields are used, connectionString takes precedence:

[codecov]

Codecov Report

Merging #1932 (d6e6090) into main (7895306) will decrease coverage by 0.01%.
Report is 1 commits behind head on main.
The diff coverage is 92.85%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1932      +/-   ##
==========================================
- Coverage   91.02%   91.02%   -0.01%     
==========================================
  Files         146      146              
  Lines        7478     7488      +10     
  Branches     1497     1502       +5     
==========================================
+ Hits         6807     6816       +9     
- Misses        671      672       +1     

Files	Coverage Δ
...de/opentelemetry-instrumentation-knex/src/utils.ts	91.48% <100.00%> (+1.24%)	⬆️
...emetry-instrumentation-knex/src/instrumentation.ts	97.67% <87.50%> (-1.11%)	⬇️

[scottgreenup]

I'm interested in this pull request getting merged, so I thought I'd add some notes.

It looks like connectionString is for both PostgreSQL and RedShift. It looks like the default port for RedShift is 5439.

I think you can check the URL protocol which should be postgres: or redshift: and set it to 5432/5439?

> (new URL("postgres://user:password@myhost/mydb")).protocol
'postgres:'

[edosrecki]

Thanks for the comment. Yes I can do that. However we cannot then cover the case of CockroachDB which uses postgres protocol, but has a different default port of 26257.

I will see how knex handles redshift connection string when port is not provided and try to match that functionality. In the end that is the right thing to do.