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Merge pull request #2 from kkostov/feature/offline-cache
Add a basic persistent local cache for signals
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64
lib/src/main/java/com/telemetrydeck/sdk/PersistentSignalCache.kt
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|---|---|---|
| @@ -0,0 +1,64 @@ | ||
| package com.telemetrydeck.sdk | ||
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| import kotlinx.serialization.json.Json | ||
| import kotlinx.serialization.decodeFromString | ||
| import kotlinx.serialization.encodeToString | ||
| import java.io.File | ||
| import java.lang.Exception | ||
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| class PersistentSignalCache(private var signalQueue: MutableList<Signal> = mutableListOf()): SignalCache { | ||
| val cacheFileName: String = "telemetrydeck.json" | ||
| var file: File? = null | ||
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| constructor(cacheDir: File, logger: DebugLogger?) : this() { | ||
| if (!cacheDir.isDirectory) { | ||
| logger?.error("Expected a folder but received a file instead.") | ||
| return | ||
| } | ||
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| val writeFile = File(cacheDir, cacheFileName) | ||
| logger?.debug("Using signal cache at ${writeFile.absolutePath}.") | ||
| if (writeFile.exists()) { | ||
| logger?.debug("Detected existing signal cache, attempting to parse...") | ||
| val content = writeFile.readText() | ||
| try { | ||
| val oldSignals: List<Signal> = Json.decodeFromString(content) | ||
| logger?.error("Restoring ${oldSignals.count()} signals from cache.") | ||
| signalQueue.addAll(oldSignals) | ||
| } catch (e: Exception) { | ||
| logger?.error("Failed to parse signal cache.") | ||
| } | ||
| } | ||
| file = writeFile | ||
| saveSignals() | ||
| } | ||
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| override fun add(signal: Signal) { | ||
| synchronized(this) { | ||
| signalQueue.add(signal) | ||
| saveSignals() | ||
| } | ||
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| } | ||
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| override fun empty(): List<Signal> { | ||
| synchronized(this) { | ||
| val items = signalQueue.toList() | ||
| signalQueue = mutableListOf() | ||
| saveSignals() | ||
| return items | ||
| } | ||
| } | ||
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| override fun count(): Int { | ||
| synchronized(this) { | ||
| return signalQueue.count() | ||
| } | ||
| } | ||
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| fun saveSignals() { | ||
| file?.createNewFile() | ||
| val json = Json.encodeToString(signalQueue) | ||
| file?.writeText(json) | ||
| } | ||
| } |
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99
lib/src/test/java/com/telemetrydeck/sdk/PersistentSignalCacheTest.kt
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,99 @@ | ||
| package com.telemetrydeck.sdk | ||
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| import androidx.arch.core.executor.testing.InstantTaskExecutorRule | ||
| import kotlinx.serialization.decodeFromString | ||
| import kotlinx.serialization.json.Json | ||
| import kotlinx.coroutines.* | ||
| import org.junit.Assert | ||
| import org.junit.Rule | ||
| import org.junit.Test | ||
| import org.junit.rules.TemporaryFolder | ||
| import java.io.File | ||
| import java.util.* | ||
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| class PersistentSignalCacheTest { | ||
| @get:Rule | ||
| val instantTaskExecutorRule = InstantTaskExecutorRule() | ||
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| @get:Rule | ||
| var folder = TemporaryFolder() | ||
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| @Test | ||
| fun persistentSignalCache_starts_with_empty_queue() { | ||
| val cacheDir = folder.newFolder() | ||
| val sut = PersistentSignalCache(cacheDir, null) | ||
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| Assert.assertEquals(0, sut.count()) | ||
| } | ||
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| @Test | ||
| fun persistentSignalCache_creates_cache_file() { | ||
| val cacheDir = folder.newFolder() | ||
| val sut = PersistentSignalCache(cacheDir, null) | ||
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| val cacheFile = File(cacheDir, sut.cacheFileName) | ||
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| Assert.assertTrue(cacheFile.exists()) | ||
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| val json = cacheFile.readText() | ||
| val signals = Json.decodeFromString<List<Signal>>(json) | ||
| Assert.assertEquals(0, signals.count()) | ||
| } | ||
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| @Test | ||
| fun persistentSignalCache_new_signals_added_to_cache() { | ||
| val cacheDir = folder.newFolder() | ||
| val sut = PersistentSignalCache(cacheDir, null) | ||
| sut.add(Signal(UUID.randomUUID(), "type", "user", SignalPayload())) | ||
| val cacheFile = File(cacheDir, sut.cacheFileName) | ||
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| val json = cacheFile.readText() | ||
| val signals = Json.decodeFromString<List<Signal>>(json) | ||
| Assert.assertEquals(1, signals.count()) | ||
| Assert.assertEquals("type", signals[0].type) | ||
| Assert.assertEquals("user", signals[0].clientUser) | ||
| } | ||
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| @Test | ||
| fun persistentSignalCache_empty_clears_cache() { | ||
| val cacheDir = folder.newFolder() | ||
| val sut = PersistentSignalCache(cacheDir, null) | ||
| sut.add(Signal(UUID.randomUUID(), "type", "user", SignalPayload())) | ||
| sut.empty() | ||
| val cacheFile = File(cacheDir, sut.cacheFileName) | ||
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| val json = cacheFile.readText() | ||
| val signals = Json.decodeFromString<List<Signal>>(json) | ||
| Assert.assertEquals(0, signals.count()) | ||
| } | ||
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| @DelicateCoroutinesApi | ||
| @Test | ||
| fun persistentSignalCache_allows_adding_signals_concurrently() = runBlocking { | ||
| val cacheDir = folder.newFolder() | ||
| val sut = PersistentSignalCache(cacheDir, null) | ||
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| // the cache should accept signals from concurrent coroutines | ||
| val scope = CoroutineScope(newFixedThreadPoolContext(4, "pool")) | ||
| scope.launch { | ||
| val coroutines = 1.rangeTo(100).map { | ||
| // create 100 coroutines (light-weight threads). | ||
| launch { | ||
| for (i in 1..20) { // and in each of them, add 20 signals | ||
| sut.add(Signal(UUID.randomUUID(), "type", "user", SignalPayload())) | ||
| } | ||
| } | ||
| } | ||
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| coroutines.forEach { coroutine -> | ||
| coroutine.join() // wait for all coroutines to finish their jobs. | ||
| } | ||
| }.join() | ||
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| val cacheFile = File(cacheDir, sut.cacheFileName) | ||
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| val json = cacheFile.readText() | ||
| val signals = Json.decodeFromString<List<Signal>>(json) | ||
| Assert.assertEquals(2000, signals.count()) | ||
| } | ||
| } |