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fix: make Remote Config LKG writes crash-durable #859

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shameondev wants to merge 1 commit into from
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fix: make Remote Config LKG writes crash-durable #859

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206 changes: 176 additions & 30 deletions sdk/src/main/java/com/qonversion/android/sdk/internal/QRemoteConfigManager.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -306,7 +306,7 @@ internal class QRemoteConfigManager @Inject constructor(
contextKey,
loadingState,
generationAtStart,
requestIdentity.cacheScope,
requestIdentity,
remoteConfig,
)
} else {
Expand All @@ -326,7 +326,19 @@ internal class QRemoteConfigManager @Inject constructor(
override fun onError(error: QonversionError) {
postIdentityAction {
if (requestIdentity.isCurrentAndStable()) {
handleRemoteConfigError(contextKey, loadingState, requestIdentity.cacheScope, error)
if (error.code == QonversionErrorCode.RemoteConfigurationNotAvailable &&
requestIdentity.cacheScope != null
) {
handleAuthoritativeRemoteConfigRemoval(
contextKey,
loadingState,
generationAtStart,
requestIdentity,
error,
)
} else {
handleRemoteConfigError(contextKey, loadingState, requestIdentity.cacheScope, error)
}
} else {
reissueSingleAfterUserChange(contextKey, loadingState)
}
Expand All @@ -335,6 +347,38 @@ internal class QRemoteConfigManager @Inject constructor(
})
}

private fun handleAuthoritativeRemoteConfigRemoval(
contextKey: String?,
loadingState: LoadingState,
generationAtStart: Int,
requestIdentity: RemoteConfigRequestIdentity,
error: QonversionError,
) {
if (invalidationGeneration.get() != generationAtStart) {
reissueSingleAfterUserChange(contextKey, loadingState)
return
}
val cacheScope = requestIdentity.cacheScope ?: run {
handleRemoteConfigError(contextKey, loadingState, null, error)
return
}
persistentCache.remove(cacheScope, contextKey) { committed ->
postIdentityAction {
when {
!requestIdentity.isCurrentAndStable() ->
reissueSingleAfterUserChange(contextKey, loadingState)
invalidationGeneration.get() != generationAtStart ->
reissueSingleAfterUserChange(contextKey, loadingState)
committed -> handleRemoteConfigError(contextKey, loadingState, cacheScope, error)
else -> {
loadingState.retryBaseline = null
fireToCallbacks(contextKey) { onError(remoteConfigPersistenceError()) }
}
}
}
}
}

private fun reissueSingleAfterUserChange(
contextKey: String?,
supersededState: LoadingState,
Expand All @@ -351,13 +395,69 @@ internal class QRemoteConfigManager @Inject constructor(
contextKey: String?,
loadingState: LoadingState,
generationAtStart: Int,
cacheScope: RemoteConfigCacheScope?,
requestIdentity: RemoteConfigRequestIdentity,
remoteConfig: QRemoteConfig,
) {
loadingState.retryBaseline = null
val currentGeneration = invalidationGeneration.get()
if (currentGeneration != generationAtStart) {
deliverOrReissueRemoteConfigSuccess(
contextKey,
loadingState,
generationAtStart,
remoteConfig,
)
return
}

val cacheScope = requestIdentity.cacheScope
if (cacheScope == null) {
deliverOrReissueRemoteConfigSuccess(
contextKey,
loadingState,
generationAtStart,
remoteConfig,
)
return
}

persistentCache.save(cacheScope, remoteConfig) { committed ->
postIdentityAction {
when {
!requestIdentity.isCurrentAndStable() ->
reissueSingleAfterUserChange(contextKey, loadingState)
invalidationGeneration.get() != generationAtStart ->
deliverOrReissueRemoteConfigSuccess(
contextKey,
loadingState,
generationAtStart,
remoteConfig,
)
committed -> deliverOrReissueRemoteConfigSuccess(
contextKey,
loadingState,
generationAtStart,
remoteConfig,
)
else -> handleRemoteConfigError(
contextKey,
loadingState,
cacheScope,
remoteConfigPersistenceError(),
)
}
}
}
}

private fun deliverOrReissueRemoteConfigSuccess(
contextKey: String?,
loadingState: LoadingState,
generationAtStart: Int,
remoteConfig: QRemoteConfig,
) {
val currentGeneration = invalidationGeneration.get()
if (currentGeneration == generationAtStart) {
cacheScope?.let { persistentCache.save(it, remoteConfig) }
deliveryOrigins[contextKey] = QRemoteConfigDeliveryOrigin.Network
loadingState.loadedConfig = remoteConfig
loadingState.generation = generationAtStart
Expand Down Expand Up @@ -418,12 +518,6 @@ internal class QRemoteConfigManager @Inject constructor(
) {
val baseline = loadingState.retryBaseline
loadingState.retryBaseline = null
if (error.code == QonversionErrorCode.RemoteConfigurationNotAvailable) {
// The server authoritatively evaluated this context and found no
// config. Keeping the old disk value would resurrect a removed
// assignment on the next transient outage.
cacheScope?.let { persistentCache.remove(it, contextKey) }
}
val canRecover = error.shouldFireRemoteConfigFallback
val lastKnownGood = if (canRecover && cacheScope != null) {
persistentCache.get(cacheScope, contextKey)
Expand Down Expand Up @@ -619,7 +713,7 @@ internal class QRemoteConfigManager @Inject constructor(
contextKeys,
includeEmptyContextKey,
callback,
requestIdentity.cacheScope,
requestIdentity,
generationAtStart,
localLoadingStates,
remoteConfigList,
Expand Down Expand Up @@ -665,34 +759,85 @@ internal class QRemoteConfigManager @Inject constructor(
"Remote Config response does not match the request",
)

private fun remoteConfigPersistenceError() = QonversionError(
QonversionErrorCode.ResponseParsingFailed,
"Remote Config could not be persisted as last known good",
)

private fun handleRemoteConfigListSuccess(
contextKeys: List<String>?,
includeEmptyContextKey: Boolean,
callback: QonversionRemoteConfigListCallback,
cacheScope: RemoteConfigCacheScope?,
requestIdentity: RemoteConfigRequestIdentity,
generationAtStart: Int,
localLoadingStates: MutableMap<String?, LoadingState>,
remoteConfigList: QRemoteConfigList,
) {
if (invalidationGeneration.get() != generationAtStart) {
// Preserve the legacy list contract: an already-valid response is
// still delivered, but a superseded evaluation is never promoted
// into either the in-memory cache or the persistent LKG.
remoteConfigList.remoteConfigs.forEach { remoteConfig ->
deliveryOrigins[remoteConfig.source.contextKey] = QRemoteConfigDeliveryOrigin.Network
}
callback.onSuccess(remoteConfigList)
return
}

val cacheScope = requestIdentity.cacheScope
if (cacheScope == null) {
completeRemoteConfigListSuccess(
callback,
generationAtStart,
localLoadingStates,
remoteConfigList,
)
return
}

reconcilePersistentCache(
contextKeys,
includeEmptyContextKey,
cacheScope,
remoteConfigList.remoteConfigs,
) { committed ->
postIdentityAction {
when {
!requestIdentity.isCurrentAndStable() ->
reissueRemoteConfigListAfterUserChange(contextKeys, includeEmptyContextKey, callback)
invalidationGeneration.get() != generationAtStart ->
reissueRemoteConfigList(contextKeys, includeEmptyContextKey, callback)
committed -> completeRemoteConfigListSuccess(
callback,
generationAtStart,
localLoadingStates,
remoteConfigList,
)
else -> remoteConfigListFallback(
contextKeys,
includeEmptyContextKey,
cacheScope,
)?.let(callback::onSuccess) ?: callback.onError(remoteConfigPersistenceError())
}
}
}
}

private fun completeRemoteConfigListSuccess(
callback: QonversionRemoteConfigListCallback,
generationAtStart: Int,
localLoadingStates: MutableMap<String?, LoadingState>,
remoteConfigList: QRemoteConfigList,
) {
remoteConfigList.remoteConfigs.forEach { remoteConfig ->
deliveryOrigins[remoteConfig.source.contextKey] = QRemoteConfigDeliveryOrigin.Network
}
if (invalidationGeneration.get() == generationAtStart) {
cacheScope?.let {
reconcilePersistentCache(
contextKeys,
includeEmptyContextKey,
it,
remoteConfigList.remoteConfigs,
)
}
remoteConfigList.remoteConfigs.forEach { remoteConfig ->
val contextKey = remoteConfig.source.contextKey
val loadingState = localLoadingStates[contextKey] ?: LoadingState()
loadingState.loadedConfig = remoteConfig
loadingState.generation = generationAtStart
localLoadingStates[contextKey] = loadingState
}
remoteConfigList.remoteConfigs.forEach { remoteConfig ->
val contextKey = remoteConfig.source.contextKey
val loadingState = localLoadingStates[contextKey] ?: LoadingState()
loadingState.loadedConfig = remoteConfig
loadingState.generation = generationAtStart
localLoadingStates[contextKey] = loadingState
}

callback.onSuccess(remoteConfigList)
Expand All @@ -703,17 +848,18 @@ internal class QRemoteConfigManager @Inject constructor(
includeEmptyContextKey: Boolean,
cacheScope: RemoteConfigCacheScope,
remoteConfigs: List<QRemoteConfig>,
completion: (Boolean) -> Unit,
) {
if (contextKeys == null) {
persistentCache.replaceAll(cacheScope, remoteConfigs)
persistentCache.replaceAll(cacheScope, remoteConfigs, completion)
return
}

val requestedContextKeys = buildList<String?> {
addAll(contextKeys)
if (includeEmptyContextKey) add(null)
}.toSet()
persistentCache.replaceRequested(cacheScope, requestedContextKeys, remoteConfigs)
persistentCache.replaceRequested(cacheScope, requestedContextKeys, remoteConfigs, completion)
}

private fun remoteConfigListFallback(
Expand Down
4 changes: 4 additions & 0 deletions sdk/src/main/java/com/qonversion/android/sdk/internal/storage/Cache.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,10 @@ internal interface Cache {
values.forEach(::putString)
}

fun updateStringsDurably(values: Map<String, String?>, removedKeys: Set<String>): Boolean {
throw UnsupportedOperationException("This cache does not provide durable atomic string updates")
}

/**
* @param defValue is returned if the String preference for key does not exist
*/
Expand Down
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