Metrics datanode (#30)

* basic metrics for datanode

* basic metrics

* basic metrics

* pull/push per sec

* throughput added

* seems done

datanode/src/datanode_server.py

@@ -10,6 +10,55 @@
 from shared_partition import clear_path
 from loguru import logger
 
+from prometheus_client import Counter, Gauge, Summary, Histogram, generate_latest, REGISTRY, start_http_server
+import os
+import time
+
+disk_total_size = Gauge('disk_total_size', 'Total size of disk', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+disk_used_size = Gauge('disk_used_size', 'Used size of disk', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+message_count = Gauge('message_count', 'Number of messages in datanode', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+push_per_sec = Histogram('push_per_sec', 'Number of pushes in second', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+pull_per_sec = Histogram('pull_per_sec', 'Number of pulls in second', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+throughput = Histogram('disk_total_size', 'Total size of disk', labelnames=["provider"], _labelvalues=[ConfigManager.get_prop('datanode_name')])
+
+
+# DECORATORS{
+def inc_message_count(func):
+    def wrapper(*args, **kwargs):
+        result = func(*args, **kwargs)
+        message_count.labels(provider=ConfigManager.get_prop('datanode_name')).inc()
+        return result
+    return wrapper
+
+
+def dec_message_count(func):
+    def wrapper(*args, **kwargs):
+        result = func(*args, **kwargs)
+        message_count.labels(provider=ConfigManager.get_prop('datanode_name')).dec()
+        return result
+    return wrapper
+
+
+def set_message_count(func):
+    def wrapper(*args, **kwargs):
+        result = func(*args, **kwargs)
+        message_count.labels(provider=ConfigManager.get_prop('datanode_name')).set(result)
+        return result
+    return wrapper
+
+
+def get_disk_info_decorator(func):
+    def wrapper():
+        result = func()
+        path = ConfigManager.get_prop('partition_home_path')
+        st = os.statvfs(path)
+        total = st.f_blocks * st.f_frsize
+        used = (st.f_blocks - st.f_bfree) * st.f_frsize
+        disk_total_size.labels(provider=ConfigManager.get_prop('datanode_name')).set(total)
+        disk_total_size.labels(provider=ConfigManager.get_prop('datanode_name')).set(used)
+        return result
+    return wrapper
+
 
 class DataNode(datanode_pb2_grpc.DataNodeServicer):
     def __init__(self, partition_count=1, home_path='datanode/server/'):
@@ -19,19 +68,28 @@ def __init__(self, partition_count=1, home_path='datanode/server/'):
         self.replica = SharedPartitions(partition_count, home_path=home_path + '/replica/')
 
 
+    @inc_message_count
     def Push(self, request, context):
+        throughput.observe(1)
+        start_time = time.time()
         logger.info(f"received a push message: {request.message}")
         if request.is_replica:
             self.replica.push(request.message)
         else:
             self.shared_partition.push(request.message)
+        end_time = time.time()
+        push_per_sec.observe(end_time - start_time)
         return empty_pb2.Empty()
 
     def Pull(self, request, context):
         try:
+            throughput.observe(1)
+            start_time = time.time()
             logger.info(f"received a pull message: {request}")
             message = self.shared_partition.pull()
             response = datanode_pb2.PullResponse(message=message)
+            end_time = time.time()
+            push_per_sec.observe(end_time - start_time)
             return response
         except grpc.RpcError as e:
             logger.exception(e)
@@ -77,8 +135,10 @@ def PurgeReplicaData(self, request, context):
                                         home_path=self.home_path + '/replica/')
         return empty_pb2.Empty()
 
+    @dec_message_count
     def AcknowledgePull(self, request, context):
         try:
+            throughput.observe(1)
             key = request.key
             logger.info(f"received an acknowledge message: {key}")
             if request.is_replica:
@@ -95,6 +155,8 @@ def IsHealthy(self, request, context):
         except grpc.RpcError as e:
             logger.exception(f"Error in acknowledging. {e}")
 
+    @get_disk_info_decorator
+    @set_message_count
     def GetRemainingMessagesCount(self, request, context):
         try:
             count = self.shared_partition.get_remaining_messages_count()
@@ -111,6 +173,8 @@ def push_to_partition(partition_index: int,
 
 
 def serve():
+    start_http_server(9000)
+
     port = ConfigManager.get_prop('server_port')
     partitions_count = int(ConfigManager.get_prop('partition_count'))
     home_path = ConfigManager.get_prop('partition_home_path')