Dagger generating multiple instances of retrofit interceptor

Question

I am new to Dagger and Retrofit. I am having issue where multiple instances of retrofit custom interceptor are being generated despite declared singleton in dagger module. I onl

Answer 1

You should not call provideRequestInterceptor directly

@Provides @Singleton
public Retrofit provideRetrofitInstance(AuthenticationRequestInterceptor authInterceptor)
{
    HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
    // set your desired log level
    logging.setLevel(HttpLoggingInterceptor.Level.BODY);

    OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

    // add session headers interceptor
    httpClient.addInterceptor(authInterceptor);

    // add logging as last interceptor
    httpClient.addInterceptor(logging);  

    return new Retrofit.Builder()
            .baseUrl(getConfig().getBaseUrl())
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .client(httpClient.build()) //for logging purpose remove later
            .build();
}

Answer 2

There is on point creating another of instance OkHttpClient.Builder within the provideRetrofitInstance method, you have already provided it in your ApiModule. Be nice and use as httpClient argument instead.

@Module
public class ApiModule
{
   private Config config;

   public ApiModule(Config config) {
      this.config = config;
   }

   @Provides @Singleton
   public OkHttpClient.Builder provideOkHttpClient()
   {
      return new OkHttpClient.Builder();
   }

   @Provides @Singleton
   public AuthenticationRequestInterceptor provideRequestInterceptor()
   {
      return new AuthenticationRequestInterceptor();
   }

   @Provides @Singleton
   public Retrofit provideRetrofitInstance(OkHttpClient.Builder httpClient, 
        AuthenticationRequestInterceptor authInterceptor)
   {
       HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
       // set your desired log level
       logging.setLevel(HttpLoggingInterceptor.Level.BODY);


        //YOU DON'T THIS LINE, REFER TO ARGUMENT LIST
       //OkHttpClient.Builder httpClient = new OkHttpClient.Builder();


      // add session headers interceptor
      httpClient.addInterceptor(authInterceptor);

      // add logging as last interceptor
      httpClient.addInterceptor(logging);  

      return new Retrofit.Builder()
            .baseUrl(getConfig().getBaseUrl())
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .client(httpClient.build()) //for logging purpose remove later
            .build();
    }
}