fix(pg): fix instrumentation of ESM-imported pg-pool

[maryliag]

The ESM imported top-level object is a Module Namespace Object per ECMA262 spec that is, apparently, incompatible with the 'PG' class object that 'pg' returns. The ".defaults" holds the equivalent of require('pg').

Fixes: #2759

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.67%. Comparing base (e8e3cbd) to head (8edfd00).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2807   +/-   ##
=======================================
  Coverage   89.66%   89.67%           
=======================================
  Files         184      184           
  Lines        8943     8946    +3     
  Branches     1834     1834           
=======================================
+ Hits         8019     8022    +3     
  Misses        924      924           

Files with missing lines	Coverage Δ
...elemetry-instrumentation-pg/src/instrumentation.ts	95.04% <100.00%> (+0.07%)	⬆️

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[pichlermarc]

Thanks for fixing this 🙂
Could you also add a test akin to the below one for pg-pool to avoid regressions?

opentelemetry-js-contrib/plugins/node/opentelemetry-instrumentation-pg/test/pg.test.ts

Lines 1098 to 1125 in d9e757f

	describe('pg (ESM)', () => {
	it('should work with ESM usage', async () => {
	await testUtils.runTestFixture({
	cwd: __dirname,
	argv: ['fixtures/use-pg.mjs'],
	env: {
	NODE_OPTIONS:
	'--experimental-loader=@opentelemetry/instrumentation/hook.mjs',
	NODE_NO_WARNINGS: '1',
	},
	checkResult: (err, stdout, stderr) => {
	assert.ifError(err);
	},
	checkCollector: (collector: testUtils.TestCollector) => {
	const spans = collector.sortedSpans;
	assert.strictEqual(spans.length, 3);
	assert.strictEqual(spans[0].name, 'pg.connect');
	assert.strictEqual(spans[0].kind, 3);
	assert.strictEqual(spans[1].name, 'test-span');
	assert.strictEqual(spans[1].kind, 1);
	assert.strictEqual(spans[2].name, 'pg.query:SELECT otel_pg_database');
	assert.strictEqual(spans[2].kind, 3);
	},
	});
	});
	});

Doing so would also check the box in #1942

[trentm]

Thanks!

If you are super-bored sometime ;) a test for this (similar to the runTestFixture usage in test/pg.test.ts) would be great. Then we could check off instrumentation-pg in #1942 (comment)

[trentm]

Oh, duh, Marc said the exact same thing already.

[maryliag]

Yes, I will be adding the test shortly :D

[pichlermarc]

thank you for fixing this 🙂