Merge pull request #315 from mendix/UPV4-160-Latency-between-app-and-…

…database

Add metric to measure TCP latency between app and database

bin/bootstrap-python

@@ -25,12 +25,9 @@ PIP_WORKDIR="${CACHE_PATH}/pip/build"
 # Set the correct Python site-packages directory to install to
 SITE_PACKAGES_PATH="${BUILD_PATH}/$(python3 -m site --user-site | cut -d '/' -f4-)"
 
-if [[ ! -d $PIP_WHEELDIR ]]
-then
-    echo " ---> Copying included wheels to cache...";
-    mkdir -p $PIP_WHEELDIR;
-    cp -rf $WHEELS_PATH/* $PIP_WHEELDIR/; 
-fi
+echo " ---> Copying included wheels to cache...";
+mkdir -p $PIP_WHEELDIR;
+cp -rf $WHEELS_PATH/* $PIP_WHEELDIR/;
 
 echo " ---> Bootstrapping pip and setuptools..."
 $PIP_CMD install --user --no-warn-script-location --no-index --find-links=$PIP_WHEELDIR --build=$PIP_WORKDIR pip setuptools

buildpack/runtime_components/metrics.py

@@ -2,10 +2,12 @@
 import json
 import logging
 import os
+import socket
 import sys
 import threading
 import time
 from abc import ABCMeta, abstractmethod
+from timeit import default_timer as timer
 
 import psycopg2
 import requests
@@ -235,6 +237,9 @@ def _inject_database_stats(self, stats):
         if mutations_stats:
             database_stats.update(mutations_stats)
         stats["database"] = database_stats
+        tcp_latency = self._get_database_tcp_latency()
+        if tcp_latency:
+            database_stats["tcp_latency"] = tcp_latency
         return stats
 
     def _get_database_storage(self):
@@ -244,6 +249,34 @@ def _get_database_storage(self):
             except ValueError:
                 return None
 
+    def _get_database_tcp_latency(self, timeout: float = 5):
+        db_config = database.get_config()
+        host, port = self._get_db_host_and_port(db_config["DatabaseHost"])
+        # New Socket and Time out
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.settimeout(timeout)
+
+        # Start a timer
+        s_start = timer()
+
+        # Try to Connect
+        try:
+            sock.connect((host, int(port)))
+            sock.shutdown(socket.SHUT_RD)
+            sock.close()
+
+        # If something bad happens, the latency is None
+        except socket.timeout:
+            return None
+        except OSError:
+            return None
+
+        # Stop Timer
+        s_stop = timer()
+        s_runtime = "%.2f" % (1000 * (s_stop - s_start))
+
+        return s_runtime
+
     def _get_database_mutations(self):
         conn = self._get_db_conn()
         db_config = database.get_config()
@@ -357,12 +390,7 @@ def _get_db_conn(self):
                     % db_config["DatabaseType"]
                 )
 
-            host_and_port = db_config["DatabaseHost"].split(":")
-            host = host_and_port[0]
-            if len(host_and_port) > 1:
-                port = int(host_and_port[1])
-            else:
-                port = 5432
+            host, port = self._get_db_host_and_port(db_config["DatabaseHost"])
             self.db = psycopg2.connect(
                 "options='-c statement_timeout=60s'",
                 database=db_config["DatabaseName"],
@@ -377,6 +405,16 @@ def _get_db_conn(self):
             )
         return self.db
 
+    @staticmethod
+    def _get_db_host_and_port(database_host):
+        host_and_port = database_host.split(":")
+        host = host_and_port[0]
+        if len(host_and_port) > 1:
+            port = int(host_and_port[1])
+        else:
+            port = 5432
+        return host, port
+
 
 class PaidAppsMetricsEmitterThread(BaseMetricsEmitterThread):
     @property

buildpack/start.py

@@ -27,7 +27,7 @@
 from buildpack.runtime_components import security
 from lib.m2ee import M2EE as m2ee_class
 
-BUILDPACK_VERSION = "4.5.2"
+BUILDPACK_VERSION = "4.5.3"
 
 m2ee = None
 app_is_restarting = False

tests/integration/test_emit_metrics.py

@@ -25,6 +25,7 @@ def test_read_metrics_in_logs(self):
         self.assert_string_in_recent_logs("storage")
         self.assert_string_in_recent_logs("number_of_files")
         self.assert_string_in_recent_logs("critical_logs_count")
+        self.assert_string_in_recent_logs("tcp_latency")
 
     def test_free_apps_metrics(self):
         self.setUpCF(