Greenbids fix geolookup: fetch from official MaxMind URL + mock dbReader UT

[EvgeniiMunin]

🔧 Type of changes

• new bid adapter
• bid adapter update
• new feature
• new analytics adapter
• new module
• module update
• bugfix
• documentation
• configuration
• dependency update
• tech debt (test coverage, refactorings, etc.)

✨ What's the context?

• GreenBids module: Ignore broken tests #3624

🧠 Rationale behind the change

• We host the GeoLite2-Country.mmdb in Greenbids GCS bucket instead of open source URL: gs://greenbids-europe-west1-prebid-server-staging/GeoLite2-Country.mmdb
• We mock the dbReader in unit test instead of loading real mmdb
• We add the logic to fallback to getCountry(ip) only in case if Device::getGeo is null (geoLookupEnabled is false in GeoLocationServiceWrapper)

🔎 New Bid Adapter Checklist

• verify email contact works
• NO fully dynamic hostnames
• geographic host parameters are NOT required
• direct use of HTTP is prohibited - implement an existing Bidder interface that will do all the job
• if the ORTB is just forwarded to the endpoint, use the generic adapter - define the new adapter as the alias of the generic adapter
• cover an adapter configuration with an integration test

🧪 Test plan

How do you know the changes are safe to ship to production?

🏎 Quality check

• Are your changes following our code style guidelines?
• Are there any breaking changes in your code?
• Does your test coverage exceed 90%?
• Are there any erroneous console logs, debuggers or leftover code in your changes?

[EvgeniiMunin]

Groovy IT is failing

Error:  Tests run: 38, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 21.95 s <<< FAILURE! -- in org.prebid.server.functional.tests.module.responsecorrenction.ResponseCorrectionSpec
Error:  org.prebid.server.functional.tests.module.responsecorrenction.ResponseCorrectionSpec.PBS should modify meta.mediaType and type for original response and also emit logs when response contains native meta.mediaType and adm without asset -- Time elapsed: 0.286 s <<< FAILURE!

I will push an empty commit to see if it is a flaky one

[EvgeniiMunin]

Also need to not forget to remove .eventually(v -> tmpFile.close()) downloadFile and find workaround for ensuring file closing

As we discussed on Slack on the current state the usage of .eventually(v -> tmpFile.close()) leads to exception on file closing
java.lang.IllegalStateException: File handle is closed as it looks like pipeTo closes file automatically. Manual closing is recommended but leads to exception.

As the current objective of this PR is to fix the PBS codebase I propose to find the solution in the PR #3596

[AntoxaAntoxic]

NPE is possible

[EvgeniiMunin]

Added optional chain

[AntoxaAntoxic]

I don't see the change

[AntoxaAntoxic]

the nature of NPE here is the case when the geolookup database hasn't been loaded, so the underlying question here is whether it's fine and the PBS should be started up in that case at all, if yes then you'd better to handle this situation appropriately

[EvgeniiMunin]

Modified to

private static String getCountryNameFromAlpha2(String isoCode) {
        return Optional.ofNullable(isoCode)
                .filter(code -> !code.isBlank())
                .map(code -> new Locale("", code))
                .map(Locale::getDisplayCountry)
                .orElse("");
    }

[AntoxaAntoxic]

databaseReaderFactory.getDatabaseReader() returns null if the file has been loaded

[EvgeniiMunin]

added optional chain + moved country extracting logic to a separate method

private String getCountry(String ip) {
        if (ip == null) {
            return null;
        }

        return Optional.ofNullable(databaseReaderFactory.getDatabaseReader())
                .map(dbReader -> getCountryFromIpUsingDatabase(dbReader, ip))
                .orElse(null);
    }

    private String getCountryFromIpUsingDatabase(DatabaseReader databaseReader, String ip) {
        try {
            final InetAddress inetAddress = InetAddress.getByName(ip);
            final CountryResponse response = databaseReader.country(inetAddress);
            final Country country = response.getCountry();
            return country.getName();
        } catch (IOException | GeoIp2Exception e) {
            throw new PreBidException("Failed to fetch country from geoLite DB", e);
        }
    }

[CTMBNara]

What about to use RemoteFileSyncerV2 instead of this class? Just configure update-interval-ms: 0. You can see example of using it with MaxMindGeoLocationService.

[EvgeniiMunin]

As I remember from our discussion with @AntoxaAntoxic , we have discussed whether to reuse or not RemoteFileSyncerV2 and the public get() method of RemoteFileSupplier called in syncer and decided to not do that and to proceed with defining methods validateResponse, sendHttpRequest, downloadFile on the side of RTD module

[CTMBNara]

                        .compose(response -> response.pipeTo(tmpFile))
                        .onComplete(result -> tmpFile.close()))

[EvgeniiMunin]

Adding tmpFile.close() manual tmpFile closing results in java.lang.IllegalStateException: File handle is closed. The reason is that after invoking response.pipeTo(tmpFile) it closes tmpFile automatically by default and then  .onComplete(result -> mpFile.close()) trying double close it and fails. We previously discussed with @AntoxaAntoxic and tried to replace onComplete with .eventually(v -> tmpFile.close()) but result was the same.

[CTMBNara]

@EvgeniiMunin Seems you are right. Then please, change it a bit in your code and in RemoteFileSupplier if you don't mind:

                .compose(tmpFile -> sendHttpRequest(...)
                        .onFailure(ignore -> tmpFile.close())
                        .compose(response -> response.pipeTo(tmpFile)))

[EvgeniiMunin]

fixed