Factor out dependency checking functions to its own class (ref T9).

scripts/check-build-env

@@ -23,34 +23,31 @@
 import os
 import sys
 
-required_packages = [
-    'sudo',
-    'make',
-    'live-build',
-    'pbuilder',
-    'devscripts',
-    'python-pystache'
-]
+import util
 
-
-def is_installed(name):
-    result = os.system("dpkg-query -W --showformat='${{Status}}\n' {name} 2>&1 | grep 'install ok installed' >/dev/null".format(name=name))
-    return True if result == 0 else False
-
-
-missing_packages = []
+deps = {
+    'packages': [
+       'sudo',
+       'make',
+       'live-build',
+       'pbuilder',
+       'devscripts',
+       'python-pystache'
+    ],
+   'binaries': []
+}
 
 print("Checking if packages required for VyOS image build are installed")
 
-for p in required_packages:
-    if not is_installed(p):
-        missing_packages.append(p)
+checker = util.DependencyChecker(deps)
 
-if missing_packages:
-    print("Your system does not have some of the required packages installed.")
-    print("Please install the following packages:")
-    print(" ".join(missing_packages))
-    sys.exit(1)
-else:
-    print("All required packages are installed")
+missing = checker.get_missing_dependencies()
+if not missing:
+    print("All dependencies are installed")
     sys.exit(0)
+else:
+    checker.print_missing_deps()
+    sys.exit(1)
+
+sys.exit(0)
+

scripts/check-vm-build-env

@@ -21,41 +21,31 @@
 
 import os
 import sys
-from distutils.spawn import find_executable
 
-required_packages = [
-    'make',
-    'qemu-system-x86',
-    'qemu-utils'
-]
+import util
 
+deps = {
+    'packages': [
+      'make',
+      'qemu-system-x86',
+      'qemu-utils'
+    ],
+   'binaries': ['packer']
+}
 
-def is_installed(name):
-    result = os.system("dpkg-query -W --showformat='${{Status}}\n' {name} 2>&1 | grep 'install ok installed' >/dev/null".format(name=name))
-    return True if result == 0 else False
+print("Checking if packages required for VyOS image build are installed")
 
+checker = util.DependencyChecker(deps)
 
-missing_packages = []
-
-print("Checking if packages required for VyOS VM image build are installed")
-
-for p in required_packages:
-    if not is_installed(p):
-        missing_packages.append(p)
-
-if missing_packages:
-    print("Your system does not have some of the required packages installed.")
-    print("Please install the following packages:")
-    print(" ".join(missing_packages))
-    sys.exit(1)
+missing = checker.get_missing_dependencies()
+if not missing:
+    print("All dependencies are installed")
+    sys.exit(0)
 else:
-    print("All required packages are installed")
-
-if find_executable("packer"):
-    print("Your system has Packer.")
-else:
-    print("Your system does not have Packer.")
-    print("Please install Packer from https://www.packer.io/downloads.html.")
+    checker.print_missing_deps()
+    if 'packer' in missing['binaries']:
+        print("Your system does not have Packer.")
+        print("Please install Packer from https://www.packer.io/downloads.html.")
     sys.exit(1)
 
 sys.exit(0)

scripts/util.py

@@ -19,6 +19,7 @@
 
 import sys
 import os
+from distutils.spawn import find_executable
 
 import defaults
 
@@ -27,3 +28,38 @@ def check_build_config():
         print("Build config file ({file}) does not exist".format(file=defaults.BUILD_CONFIG))
         print("If you are running this script by hand, you should better not. Run 'make iso' instead.")
         sys.exit(1)
+
+
+class DependencyChecker(object):
+    def __init__(self, spec):
+        missing_packages = self._get_missing_packages(spec['packages'])
+        missing_binaries = self._get_missing_binaries(spec['binaries'])
+        self.__missing = {'packages': missing_packages, 'binaries': missing_binaries}
+
+
+    def _package_installed(self, name):
+        result = os.system("dpkg-query -W --showformat='${{Status}}\n' {name} 2>&1 | grep 'install ok installed' >/dev/null".format(name=name))
+        return True if result == 0 else False
+
+    def _get_missing_packages(self, packages):
+        missing_packages = []
+        for p in packages:
+            if not self._package_installed(p):
+                missing_packages.append(p)
+        return missing_packages
+
+    def _get_missing_binaries(self, binaries):
+        missing_binaries = []
+        for b in binaries:
+            if not find_executable(b):
+                missing_binaries.append(b)
+        return missing_binaries
+
+    def get_missing_dependencies(self):
+        if self.__missing['packages'] or self.__missing['binaries']:
+            return self.__missing
+        return None
+
+    def print_missing_deps(self):
+        print("Missing packages: " + " ".join(self.__missing['packages']))
+        print("Missing binaries: " + " ".join(self.__missing['binaries']))