Package com.github.ambry.quota.storage

Interface StorageQuotaEnforcer

public interface StorageQuotaEnforcer

StorageQuotaEnforcer enforces the traffic throttling based on the storage quota and the current storage usage. Each traffic that changes storage usage is targeted at a specific account and container. Enforcer enforces storage quota on each container. Before evaluating any traffic, enforcer has to retrieve storage quota of each container from StorageQuotaSource and current storage usage of each container from StorageUsageRefresher, by calling initStorageQuota(java.util.Map<java.lang.String, java.util.Map<java.lang.String, java.lang.Long>>) and initStorageUsage(java.util.Map<java.lang.String, java.util.Map<java.lang.String, java.lang.Long>>) respectively. Container storage quota can be dynamic, it can be updated to increase or decrease the quota for specific containers. To listen on these changes, Enforcer would return a StorageQuotaSource.Listener. Container storage usage is changing all the the time because of expired blobs and compacted deleted blobs. That's the reason why relying on the incoming traffic won't give you a correct answer about the current storage usage. For instance, if 1GB blob is uploaded to containerA and the TTL for this blob is one day. Then one day later, without any traffic from client, the storage usage for containerA becomes 0. Since the storage usage from StorageUsageRefresher is the source of the truth, enforcer has to listen on the changes for storage usage and replace the value in memory with the value from StorageUsageRefresher.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	StorageQuotaEnforcer.QuotaExceededCallback	Interface of callback method when the quota of certain account and container's quota is exceeded.

Method Summary

Modifier and Type	Method	Description
void	initStorageQuota(java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>> quota)	Initialize the storage quota in StorageQuotaSource.
void	initStorageUsage(java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>> usage)	Initialize the storage usage in StorageQuotaEnforcer.
void	registerListeners(StorageQuotaSource storageQuotaSource, StorageUsageRefresher storageUsageRefresher)	Register listeners in StorageQuotaSource and StorageUsageRefresher.
void	setQuotaMode(QuotaMode mode)	Change the StorageQuotaEnforcer's mode to the given value.
boolean	shouldThrottle(short accountId, short containerId, QuotaOperation op, long size)	Return true if the given QuotaOperation should be throttled.

Method Detail

initStorageUsage

void initStorageUsage(java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>> usage)

Initialize the storage usage in StorageQuotaEnforcer.

Parameters:

usage - The initial storage usage from StorageUsageRefresher.

initStorageQuota

void initStorageQuota(java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>> quota)

Initialize the storage quota in StorageQuotaSource.

Parameters:

quota - The initial quota from StorageQuotaSource.

registerListeners

void registerListeners(StorageQuotaSource storageQuotaSource,
                       StorageUsageRefresher storageUsageRefresher)

Register listeners in StorageQuotaSource and StorageUsageRefresher.

Parameters:

storageQuotaSource - The StorageQuotaSource to register listener.

storageUsageRefresher - The StorageUsageRefresher to register listener.

shouldThrottle

boolean shouldThrottle(short accountId,
                       short containerId,
                       QuotaOperation op,
                       long size)

Return true if the given QuotaOperation should be throttled.

Parameters:

accountId - The accountId of this operation.

containerId - The containerId of this operation.

op - The QuotaOperation.

size - The size of this operation. eg, if the op is QuotaOperation.Post, size if the size of the content.

Returns:

True if the given QuotaOperation should be throttled.

setQuotaMode

void setQuotaMode(QuotaMode mode)

Change the StorageQuotaEnforcer's mode to the given value. If the mode is QuotaMode.Tracking, then StorageQuotaEnforcer should never return true in shouldThrottle(short, short, com.github.ambry.quota.storage.QuotaOperation, long) method.

Parameters:

mode - The new value for QuotaMode.