Move install script error handling to a common function

All of our install/admin scripts had a try/except block calling the
main function and handling common exceptions. These were copy-pasted
from each other and modified to various levels of sophistication.
This refactors them out of installers to a single function, which
includes a final pass/fail message for all of the scripts.

Non-install scripts that set up the same log handler levels for
stderr and log file are not changed, as it's not possible to log
to only the logfile without changing the logger configuration.

https://fedorahosted.org/freeipa/ticket/2071

install/tools/ipa-ca-install

@@ -21,7 +21,7 @@
 import sys
 import socket
 
-import os, traceback, shutil
+import os, shutil
 
 from ipapython import ipautil
 from ipapython import services as ipaservices
@@ -39,8 +39,9 @@ from ipapython.config import IPAOptionParser
 from ipapython import sysrestore
 from ipapython.ipa_log_manager import *
 
-CACERT="/etc/ipa/ca.crt"
-REPLICA_INFO_TOP_DIR=None
+log_file_name = "/var/log/ipareplica-ca-install.log"
+CACERT = "/etc/ipa/ca.crt"
+REPLICA_INFO_TOP_DIR = None
 
 def parse_options():
     usage = "%prog [options] REPLICA_FILE"
@@ -72,7 +73,12 @@ def get_dirman_password():
 
 def main():
     safe_options, options, filename = parse_options()
-    standard_logging_setup("/var/log/ipareplica-ca-install.log", debug=options.debug)
+
+    if os.geteuid() != 0:
+        sys.exit("\nYou must be root to run this script.\n")
+
+    standard_logging_setup(log_file_name, debug=options.debug)
+
     root_logger.debug('%s was invoked with argument "%s" and options: %s' % (sys.argv[0], filename, safe_options))
 
     if not ipautil.file_exists(filename):
@@ -150,41 +156,20 @@ def main():
     # We need to restart apache as we drop a new config file in there
     ipaservices.knownservices.httpd.restart(capture_output=True)
 
-try:
-    if not os.geteuid()==0:
-        sys.exit("\nYou must be root to run this script.\n")
+fail_message = '''
+Your system may be partly configured.
+Run /usr/sbin/ipa-server-install --uninstall to clean up.
+'''
 
-    main()
-    sys.exit(0)
-except SystemExit, e:
-    sys.exit(e)
-except socket.error, (errno, errstr):
-    print errstr
-except HostnameLocalhost:
-    print "The hostname resolves to the localhost address (127.0.0.1/::1)"
-    print "Please change your /etc/hosts file so that the hostname"
-    print "resolves to the ip address of your network interface."
-    print ""
-    print "Please fix your /etc/hosts file and restart the setup program"
-except Exception, e:
-    print "creation of replica failed: %s" % str(e)
-    message = str(e)
-    for str in traceback.format_tb(sys.exc_info()[2]):
-        message = message + "\n" + str
-    root_logger.debug(message)
-except KeyboardInterrupt:
-    print "Installation cancelled."
-finally:
-    # always try to remove decrypted replica file
+if __name__ == '__main__':
     try:
-        if REPLICA_INFO_TOP_DIR:
-            shutil.rmtree(REPLICA_INFO_TOP_DIR)
-    except OSError:
-        pass
-
-print ""
-print "Your system may be partly configured."
-print "Run /usr/sbin/ipa-server-install --uninstall to clean up."
-
-# the only way to get here is on error or ^C
-sys.exit(1)
+        installutils.run_script(main, log_file_name=log_file_name,
+                operation_name='ipa-ca-install',
+                fail_message=fail_message)
+    finally:
+        # always try to remove decrypted replica file
+        try:
+            if REPLICA_INFO_TOP_DIR:
+                shutil.rmtree(REPLICA_INFO_TOP_DIR)
+        except OSError:
+            pass