TP-54316 | Retry Mechanism System (#9363)

Co-authored-by: Shivam Goyal <shivam.goyal@navi.com>

navi-base/build.gradle

@@ -83,6 +83,8 @@ dependencies {
 
     testImplementation libs.junit
 
+    testImplementation libs.kotlinx.coroutines.test
+
     testImplementation libs.mockk
 }
 

navi-base/src/main/java/com/navi/base/utils/Retry.kt

@@ -0,0 +1,85 @@
+/*
+ *
+ *  * Copyright © 2024 by Navi Technologies Limited
+ *  * All rights reserved. Strictly confidential
+ *
+ */
+
+package com.navi.base.utils
+
+import kotlin.math.pow
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.seconds
+import kotlinx.coroutines.delay
+
+/**
+ * Linear with retryIntervalInSeconds of 3 secs means at T = 0, 3, 6, 9, 12, ... execute will be
+ * called
+ *
+ * Exponential with retryIntervalInSeconds of 3 secs means 0, 3, 9, 27, 81, ...
+ */
+enum class RetryStrategy {
+    LINEAR,
+    EXPONENTIAL
+}
+
+/**
+ * For retryCount n means, execute will be called at max n+1 times. 1 time for normal execution &
+ * then n times for retry
+ *
+ * @param retryCount should be >= 0. It says after 1st execution, how many times should we retry
+ */
+suspend fun <T> retry(
+    retryCount: Int = 3,
+    retryIntervalInSeconds: Double = 0.0,
+    retryStrategy: RetryStrategy = RetryStrategy.LINEAR,
+    execute: suspend () -> T,
+    shouldRetry: (T) -> Boolean
+): T {
+
+    if (retryCount < 1) throw IllegalArgumentException("retryCount should be >= 0")
+
+    if (retryIntervalInSeconds < 0)
+        throw IllegalArgumentException("retryIntervalInSeconds should be >= 0")
+
+    // Default execute
+    var result = execute()
+
+    // If result is success & retry is not needed, return result
+    if (!shouldRetry(result)) {
+        return result
+    }
+
+    // Default execute has failed & retry should start
+    for (i in 1..retryCount) {
+        delay(
+            getDelayDuration(
+                retryIntervalInSeconds = retryIntervalInSeconds,
+                retryStrategy = retryStrategy,
+                retryCount = i
+            )
+        )
+
+        result = execute()
+
+        // If retry is success, return retryResult
+        if (!shouldRetry(result)) {
+            return result
+        }
+    }
+
+    // All retry count has exhausted, return the last result
+    return result
+}
+
+/** This function is made internal only for testing purpose & is not intended to be used directly */
+internal fun getDelayDuration(
+    retryIntervalInSeconds: Double,
+    retryStrategy: RetryStrategy,
+    retryCount: Int
+): Duration {
+    return when (retryStrategy) {
+        RetryStrategy.LINEAR -> (retryIntervalInSeconds * retryCount).seconds
+        RetryStrategy.EXPONENTIAL -> (retryIntervalInSeconds.pow(retryCount)).seconds
+    }
+}

navi-base/src/test/java/com/navi/base/utils/RetryUtilTest.kt

@@ -0,0 +1,169 @@
+/*
+ *
+ *  * Copyright © 2024 by Navi Technologies Limited
+ *  * All rights reserved. Strictly confidential
+ *
+ */
+
+package com.navi.base.utils
+
+import kotlin.time.Duration.Companion.seconds
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class RetryUtilTest {
+
+    @Test
+    fun `linear retry strategy delay duration test`() = runTest {
+        var retryIntervalInSeconds = 3.0
+
+        assertEquals(3.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 1))
+        assertEquals(6.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 2))
+        assertEquals(9.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 3))
+
+        retryIntervalInSeconds = 0.0
+
+        assertEquals(0.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 1))
+        assertEquals(0.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 2))
+        assertEquals(0.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 3))
+
+        retryIntervalInSeconds = 1.0
+
+        assertEquals(1.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 1))
+        assertEquals(2.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 2))
+        assertEquals(3.seconds, getDelayDuration(retryIntervalInSeconds, RetryStrategy.LINEAR, 3))
+    }
+
+    @Test
+    fun `exponential retry strategy delay duration test`() = runTest {
+        var retryIntervalInSeconds = 3.0
+
+        assertEquals(
+            3.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 1)
+        )
+        assertEquals(
+            9.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 2)
+        )
+        assertEquals(
+            27.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 3)
+        )
+
+        retryIntervalInSeconds = 0.0
+
+        assertEquals(
+            0.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 1)
+        )
+        assertEquals(
+            0.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 2)
+        )
+        assertEquals(
+            0.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 3)
+        )
+
+        retryIntervalInSeconds = 1.0
+
+        assertEquals(
+            1.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 1)
+        )
+        assertEquals(
+            3.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 2)
+        )
+        assertEquals(
+            9.seconds,
+            getDelayDuration(retryIntervalInSeconds, RetryStrategy.EXPONENTIAL, 3)
+        )
+    }
+
+    @Test
+    fun `test number of times execute is getting invoked for all execute failing & asking retry with retryCount as 3`() =
+        runTest {
+            var executeCount = 0
+            val execute = {
+                executeCount++
+                1
+            }
+            val shouldRetry: (Any) -> Boolean = { true }
+
+            retry(
+                retryCount = 3,
+                retryIntervalInSeconds = 3.0,
+                retryStrategy = RetryStrategy.LINEAR,
+                execute = execute,
+                shouldRetry = shouldRetry
+            )
+
+            assertEquals(4, executeCount)
+        }
+
+    @Test
+    fun `test number of times execute is getting invoked for 1st instance of execute getting success for retryCount as 3`() =
+        runTest {
+            var executeCount = 0
+            val execute = {
+                executeCount++
+                1
+            }
+            val shouldRetry: (Any) -> Boolean = { false }
+
+            retry(
+                retryCount = 3,
+                retryIntervalInSeconds = 3.0,
+                retryStrategy = RetryStrategy.LINEAR,
+                execute = execute,
+                shouldRetry = shouldRetry
+            )
+
+            assertEquals(1, executeCount)
+        }
+
+    @Test
+    fun `test number of times execute is getting invoked for 2nd instance of execute getting success for retryCount as 3`() =
+        runTest {
+            var executeCount = 0
+            val execute = {
+                executeCount++
+                1
+            }
+            val shouldRetry: (Any) -> Boolean = { executeCount == 1 }
+
+            retry(
+                retryCount = 3,
+                retryIntervalInSeconds = 3.0,
+                retryStrategy = RetryStrategy.LINEAR,
+                execute = execute,
+                shouldRetry = shouldRetry
+            )
+
+            assertEquals(2, executeCount)
+        }
+
+    @Test
+    fun `test number of times execute is getting invoked for 3rd instance of execute getting success for retryCount as 3`() =
+        runTest {
+            var executeCount = 0
+            val execute = {
+                executeCount++
+                1
+            }
+            val shouldRetry: (Any) -> Boolean = { executeCount <= 2 }
+
+            retry(
+                retryCount = 3,
+                retryIntervalInSeconds = 3.0,
+                retryStrategy = RetryStrategy.LINEAR,
+                execute = execute,
+                shouldRetry = shouldRetry
+            )
+
+            assertEquals(3, executeCount)
+        }
+}