arguments parser

vm.py

 import libvirt
-import sys
+import sys, getopt, os
 import uuid
 from jinja2 import Environment, select_autoescape, FileSystemLoader
 import subprocess
 
 from utils import fwd_port, show_ip
 
-try:
-    conn = libvirt.open("qemu:///system")
-except libvirt.libvirtError:
-    print('Failed to open connection to the hypervisor')
-    sys.exit(1)
-
 file_loader = FileSystemLoader('templates')
 
 env = Environment(autoescape=select_autoescape(
@@ -33,44 +27,52 @@ params = {
     "boot_menu": "yes",
 }
 
-template = env.get_template("demovm.xml")
+def start_vm(params):
 
-vmxml = template.render(
+    template = env.get_template("demovm.xml")
+
+    vmxml = template.render(
         **params
-)
+    )
+
+    print(vmxml)
 
-print(vmxml)
+    input("Correct? ")
 
-input("Correct? ")
+    try:
+        conn = libvirt.open("qemu:///system")
+    except libvirt.libvirtError:
+        print('Failed to open connection to the hypervisor')
+        sys.exit(1)
 
-id = params["uuid"]
-bus = params["mdev_bus"]
-vgpu = params["vgpu_type"]
+    id = params["uuid"]
 
-if params["vgpu"]:
+    if params["vgpu"]:
+        bus = params["mdev_bus"]
+        vgpu = params["vgpu_type"]
         print("Allocating VGPU instance for the VM")
         try:
             subprocess.run([f"sudo bash create_vgpu.sh {id} {bus} {vgpu}"], check=True, shell=True, stderr=subprocess.STDOUT)
         except subprocess.CalledProcessError as e:
             raise RuntimeError("command '{}' return with error (code {}): {}".format(e.cmd, e.returncode, e.output))
 
-try:
+    try:
         dom = conn.defineXML(vmxml)
         if not dom:
             raise SystemExit("Failed to define a domain from an XML definition")
         print("Start VM")
         if dom.create() < 0:
             raise SystemExit("Can not boot guest domain")
-except libvirt.libvirtError:
+    except libvirt.libvirtError:
         print('Failed to find the main domain')
         sys.exit(1)
 
-print("Domain 0: id %d running %s" % (dom.ID(), dom.OSType()))
-print(dom.info())
+    print("Domain 0: id %d running %s" % (dom.ID(), dom.OSType()))
+    print(dom.info())
 
-print("Type stop, to shutdown vm!")
-cmd = input()
-while cmd != "stop":
+    print("Type stop, to shutdown vm!")
+    cmd = input()
+    while cmd != "stop":
         cmdarr = cmd.split()
         if cmdarr[0] == "fwd":
             fwd_port(dom, int(cmdarr[1]), int(cmdarr[2]))
@@ -78,15 +80,15 @@ while cmd != "stop":
             show_ip(dom)
         cmd = input()
 
-try:
+    try:
         print("Stop VM")
         if dom.destroy() < 0:
             raise SystemExit("Can not stop guest domain")
-except libvirt.libvirtError:
+    except libvirt.libvirtError:
         print('Failed to find the main domain')
         sys.exit(1)    
 
-if params["vgpu"]:
+    if params["vgpu"]:
         print("Deallocating VGPU instance from the VM")
         try:
             subprocess.run([f"sudo bash remove_vgpu.sh {id} {bus} {vgpu}"], check=True, shell=True, stderr=subprocess.STDOUT)
@@ -94,4 +96,34 @@ if params["vgpu"]:
             raise RuntimeError("command '{}' return with error (code {}): {}".format(e.cmd, e.returncode, e.output))
 
 
-conn.close()
\ No newline at end of file
+    conn.close()
+
+
+def main():
+    try:
+        opts, args = getopt.getopt(sys.argv[1:], "gbmcd:v", ["help", "output="])
+    except getopt.GetoptError as err:
+        # print help information and exit:
+        print(err)  # will print something like "option -a not recognized"
+        sys.exit(2)
+    for o, a in opts:
+        if o in ("-m", "--mem"):
+            params["ram"] = int(a)
+        elif o in ("-g", "--gpu"):
+            params["vgpu"] = True
+            params["vgpu_type"] = a
+        elif o in ("-b", "--boot"):
+            params["boot_iso"] = True
+            params["iso"] = a
+            if not os.path.isfile(a):
+                raise RuntimeError("The attached boot iso is not a file or not exists")
+        elif o in ("-c", "--cpu"):
+            params["vcpu"] = int(a)
+        elif o in ("-d", "--disk"):
+            params["disk"] = a
+            if not os.path.isfile(a):
+                raise RuntimeError("The attached disk is not a file or not exists")
+        else:
+            assert False, "unhandled option"
+
+    start_vm(params)
\ No newline at end of file