Rewrite Java code to Kotlin

examples/README.md

@@ -2,12 +2,19 @@
 
 Requires Java 17
 
-You will require an `application-local.yaml` file. It will look something like this:
+You will require an `application-local.yml` file. It will look something like this:
 
 ```yaml
 firetail:
   apikey: "PS-02....441b09761c3"
   url: "https://your-apiapi.logging.eu-north-west-99.sandbox.firetail.app"
+  ## Cache control before dispatching logs to API
+  buffer:
+    # Millis
+    interval: 100000
+    # Max capacity
+    capacity: 5
+
 ```
 
 Firstly, build the Firetail-Java-Library
@@ -19,6 +26,8 @@ cd ..
 # Run the example
 cd examples
 ./gradlew bootRun
+# By default, you'll want to hit this endpoint 5 times before the logs are dispatched
+# Otherwise hit it < 5 and wait for 10 seconds
 curl http://localhost:8080/hello
 ```
 

src/main/kotlin/io/firetail/logging/core/FiretailBuffer.kt

@@ -1,12 +1,14 @@
 package io.firetail.logging.core
 
+import io.firetail.logging.core.FiretailLogger.Companion.LOGGER
 import io.firetail.logging.servlet.FiretailMapper
 import io.firetail.logging.spring.FiretailConfig
 import org.slf4j.LoggerFactory
 import java.util.*
 import java.util.concurrent.Executors
 import java.util.concurrent.ScheduledExecutorService
 import java.util.concurrent.TimeUnit
+import java.util.concurrent.locks.ReentrantLock
 
 class FiretailBuffer(
     private val firetailConfig: FiretailConfig,
@@ -16,6 +18,7 @@ class FiretailBuffer(
     private val buffer: MutableList<FiretailData> = mutableListOf()
     private val scheduler: ScheduledExecutorService = Executors.newSingleThreadScheduledExecutor()
     private val flushCallback = mutableListOf<FiretailData>()
+    private val bufferLock = ReentrantLock()
 
     init {
         // Schedule the periodic flush task
@@ -31,19 +34,31 @@ class FiretailBuffer(
         )
     }
 
+    // Caller sycronizes access before calling this function
     fun add(item: FiretailData) {
-        buffer.add(item)
-        if (buffer.size >= firetailConfig.capacity) {
-            flush()
+        bufferLock.lock()
+        try {
+            buffer.add(item)
+            if (buffer.size >= firetailConfig.capacity) {
+                flush()
+            }
+        } finally {
+            bufferLock.unlock()
         }
     }
 
+    // Threadsafe - write and reset the cached data
     fun flush(): String {
-        if (buffer.isNotEmpty()) {
-            LOGGER.debug("Buffer flushing ${buffer.size}")
-            val result = firetailTemplate.send(buffer.toList())
-            buffer.clear()
-            return firetailMapper.getResult(result)
+        bufferLock.lock()
+        try {
+            if (buffer.isNotEmpty()) {
+                LOGGER.debug("Buffer flushing ${buffer.size}")
+                val result = firetailTemplate.send(buffer)
+                buffer.clear()
+                return firetailMapper.getResult(result)
+            }
+        } finally {
+            bufferLock.unlock()
         }
         return ""
     }

src/main/kotlin/io/firetail/logging/servlet/FiretailFilter.kt

@@ -4,9 +4,9 @@ import io.firetail.logging.core.Constants.Companion.CORRELATION_ID
 import io.firetail.logging.core.Constants.Companion.OP_NAME
 import io.firetail.logging.core.Constants.Companion.REQUEST_ID
 import io.firetail.logging.core.FiretailBuffer
-import io.firetail.logging.spring.FiretailConfig
 import io.firetail.logging.core.FiretailLogger
 import io.firetail.logging.core.FiretailTemplate
+import io.firetail.logging.spring.FiretailConfig
 import io.firetail.logging.util.FiretailMDC
 import jakarta.servlet.FilterChain
 import jakarta.servlet.http.HttpServletRequest
@@ -75,9 +75,7 @@ class FiretailFilter(
                             )
                         CompletableFuture.runAsync {
                             try {
-                                synchronized(firetailBuffer) {
-                                    firetailBuffer.add(firetailLog)
-                                }
+                                firetailBuffer.add(firetailLog)
                             } catch (e: Exception) {
                                 LOGGER.error(e.message)
                                 throw e

src/test/kotlin/io/firetail/logging/RequestInterceptorTests.kt

@@ -2,12 +2,12 @@ package io.firetail.logging
 
 import io.firetail.logging.core.Constants
 import io.firetail.logging.core.FiretailBuffer
-import io.firetail.logging.spring.EnableFiretail
 import io.firetail.logging.core.FiretailLogger
 import io.firetail.logging.core.FiretailTemplate
 import io.firetail.logging.servlet.FiretailFilter
 import io.firetail.logging.servlet.FiretailHeaderInterceptor
 import io.firetail.logging.servlet.FiretailMapper
+import io.firetail.logging.spring.EnableFiretail
 import io.firetail.logging.util.FiretailMDC
 import io.firetail.logging.util.StringUtils
 import org.assertj.core.api.Assertions.assertThat
@@ -37,6 +37,7 @@ import org.springframework.web.client.RestTemplate
 @TestPropertySource(
     properties = [
         "firetail.url=http://localhost:\${wiremock.server.port}",
+        "firetail.buffer.capacity=5",
     ],
 )
 @EnableFiretail