adding option to set containers based on workers memory

CONTRIBUTING

@@ -7,8 +7,8 @@ can help
 
 * Fork the latest branch of the component you want to contribute to
 * Make sure you have a [GitHub account](https://github.com/signup/free)
-* Use virtualenv to install all requirements from the requirements.txt file
-* Fix the issue you \ add a feature
+* Use virtualenv to install all requirements from the requirements.txt file, this will require having GCC compiler, python2-dev & linux-headers depending on your environment setup due to psutil requiring compilation on some OS.
+* Fix the issue you want \ add a feature
 * Create a pull request
 
 ## Design philosophy

functions/misc/server.py

@@ -1,4 +1,4 @@
-import multiprocessing, os, sys
+import multiprocessing, os, sys, psutil
 
 
 # return numbers of cores
@@ -10,3 +10,15 @@ def get_number_of_cpu_cores():
         print >> sys.stderr, e
         print("error getting the number of cpu core")
         os._exit(2)
+
+
+# return numbers of cores
+def get_total_memory_size_in_mb():
+    try:
+        memory_in_bytes = psutil.virtual_memory()
+        total_memory_in_mb = int(memory_in_bytes.total / 1024 / 1024)
+        return total_memory_in_mb
+    except Exception as e:
+        print >> sys.stderr, e
+        print("error getting the number of cpu core")
+        os._exit(2)

requirements.txt

@@ -8,6 +8,7 @@ freeze==1.0.10
 idna==2.7
 ipaddress==1.0.22
 NebulaPythonSDK==2.0.0
+psutil==5.5.0
 requests==2.20.0
 retrying==1.3.3
 six==1.11.0

worker.py

@@ -156,6 +156,8 @@ def containers_required(app_json):
     for scale_type, scale_amount in app_json["containers_per"].iteritems():
         if scale_type == "cpu":
             containers_needed = int(cpu_cores * scale_amount)
+        elif scale_type == "memory" or scale_type == "mem":
+            containers_needed = int(total_memory_size_in_mb / scale_amount)
         elif scale_type == "server" or scale_type == "instance":
             containers_needed = int(scale_amount)
     return containers_needed
@@ -214,6 +216,9 @@ def get_device_group_info(nebula_connection_object, device_group_to_get_info):
         # get number of cpu cores on host
         cpu_cores = get_number_of_cpu_cores()
 
+        # get total memory on the host in mb
+        total_memory_size_in_mb = get_total_memory_size_in_mb()
+
         # work against docker socket
         docker_socket = DockerFunctions()