raffers/iplocations

Teaching Material

Crezco Practical Task

Build a micro-service that would use any 3rd party location-from-IP address service.

• External Provider - In my case I've opted to use FreeIP
• Persistence - Uses MongoDb
  • Stores looked up values
  • Provides a fallback when the external provider lookup fails (If we've previously looked up that value successfully before)
• Caching
  • Uses the built in InMemoryCache provided by AspNet.Core. An Improvement here would be to move to a distributed cache.
  • Expiration times are configurable in appsettings.
• Testing - Using xUnit
  • Integration tests primarily used for overarching behaviours.
  • Unit tests mostly used to quickly test behaviours around isolated utilities. All done using xUnit.

Self-Review

• Test coverage could be higher
  • Could have unit tests covering the FreeIpClient to ensure the test is being well formed.
  • Could use wiremock or a stub HttpMessageHandler in the integration tests instead of stubbing the IFreeApiClient.
  • Could have some unit tests around the DI setup to test different configurations. Though since there isn't much complex logic in the DI setup these tests aren't sorely missed.
• Caching could do with some different configuration in cases where the external api fails and falls back to our persisted values. These values should be cached for less time (if at all).
  • Could also do with using a distributed cache to minimize duplicate calls from replicas needlessly increasing the external rate limit.

To Run

The simplest way to run is to execute the below:

docker-compose up -d ip-locations

Swagger UI will be available at http://localhost:5100/swagger/index.html

Tests

To run tests you must have a mongodb instance running. So you must run either the above snippet or:

docker-compose up -d mongodb

Then you can run dotnet test from the solution directory.