KTOR-5915 Warn when the RateLimit plugin installed after the routing (#3615)

Author: rsinukov1

ktor-server/ktor-server-plugins/ktor-server-auth/jvmAndNix/src/io/ktor/server/auth/AuthenticationInterceptors.kt

@@ -171,10 +171,10 @@ private fun AuthenticationConfig.findProviders(
 private fun AuthenticationConfig.findProvider(configurationName: String?): AuthenticationProvider {
     return providers[configurationName] ?: throw IllegalArgumentException(
         if (configurationName == null) {
-            "Default authentication configuration was not found"
+            "Default authentication configuration was not found. "
         } else {
-            "Authentication configuration with the name $configurationName was not found"
-        }
+            "Authentication configuration with the name $configurationName was not found. "
+        } + "Make sure that you install Authentication plugin before you use it in Routing"
     )
 }
 

ktor-server/ktor-server-plugins/ktor-server-rate-limit/jvmAndNix/src/io/ktor/server/plugins/ratelimit/RateLimitInterceptors.kt

@@ -35,7 +35,10 @@ internal val RateLimitApplicationInterceptors = createApplicationPlugin(
 private fun PluginBuilder<RateLimitInterceptorsConfig>.rateLimiterPluginBuilder() {
     val configs = application.attributes.getOrNull(RateLimiterConfigsRegistryKey) ?: emptyMap()
     val providers = pluginConfig.providerNames.map { name ->
-        configs[name] ?: throw IllegalStateException("Rate limit provider with name $name is not configured")
+        configs[name] ?: throw IllegalStateException(
+            "Rate limit provider with name $name is not configured. " +
+                "Make sure that you install RateLimit plugin before you use it in Routing"
+        )
     }
     val registry = application.attributes.computeIfAbsent(RateLimiterInstancesRegistryKey) { ConcurrentMap() }
     val clearOnRefillJobs = ConcurrentMap<ProviderKey, Job>()

ktor-server/ktor-server-tests/jvmAndNix/test/io/ktor/tests/server/plugins/RateLimitTest.kt

@@ -541,7 +541,11 @@ class RateLimitTest {
         val error = assertFailsWith<IllegalStateException> {
             startApplication()
         }
-        assertEquals("Rate limit provider with name RateLimitName(name=other_name) is not configured", error.message)
+        assertEquals(
+            "Rate limit provider with name RateLimitName(name=other_name) is not configured. " +
+                "Make sure that you install RateLimit plugin before you use it in Routing",
+            error.message
+        )
     }
 
     @Test
@@ -563,7 +567,8 @@ class RateLimitTest {
             startApplication()
         }
         assertEquals(
-            "Rate limit provider with name RateLimitName(name=KTOR_NO_NAME_RATE_LIMITER) is not configured",
+            "Rate limit provider with name RateLimitName(name=KTOR_NO_NAME_RATE_LIMITER) is not configured. " +
+                "Make sure that you install RateLimit plugin before you use it in Routing",
             error.message
         )
     }
@@ -586,7 +591,11 @@ class RateLimitTest {
         val error = assertFailsWith<IllegalStateException> {
             startApplication()
         }
-        assertEquals("Rate limit provider with name RateLimitName(name=name) is not configured", error.message)
+        assertEquals(
+            "Rate limit provider with name RateLimitName(name=name) is not configured. " +
+                "Make sure that you install RateLimit plugin before you use it in Routing",
+            error.message
+        )
     }
 
     @Test