Framework for admin/install tools, with ipa-ldap-updater

Currently, FreeIPA's install/admin scripts are long pieces of code
that aren't very reusable, importable, or testable.
They have been extended over time with features such as logging and
error handling, but since each tool was extended individually, there
is much inconsistency and code duplication.
This patch starts a framework which the admin tools can use, and
converts ipa-ldap-updater to use the framework.

Common tasks the tools do -- option parsing, validation, logging
setup, error handling -- are represented as methods. Individual
tools can extend, override or reuse the defaults as they see fit.

The ipa-ldap-updater has two modes (normal and --upgrade) that
don't share much functionality. They are represented by separate
classes. Option parsing, and selecting which class to run, happens
before they're instantiated.

All code is moved to importable modules to aid future testing. The
only thing that remains in the ipa-ldap-updater script is a two-line
call to the library.

First part of the work for:
https://fedorahosted.org/freeipa/ticket/2652

1 files changed, 41 insertions, 51 deletions

diff --git a/ipaserver/install/installutils.py b/ipaserver/install/installutils.py
index 903e8f185..388a11e26 100644
--- a/ipaserver/install/installutils.py
+++ b/ipaserver/install/installutils.py
@@ -32,12 +32,14 @@ import tempfile
 import shutil
 from ConfigParser import SafeConfigParser
 import traceback
+import textwrap
 
 from dns import resolver, rdatatype
 from dns.exception import DNSException
 import ldap
 
-from ipapython import ipautil, sysrestore
+from ipapython import ipautil, sysrestore, admintool
+from ipapython.admintool import ScriptError
 from ipapython.ipa_log_manager import *
 from ipalib.util import validate_hostname
 from ipapython import config
@@ -61,18 +63,6 @@ class HostReverseLookupError(HostLookupError):
 class HostnameLocalhost(HostLookupError):
     pass
 
-
-class ScriptError(StandardError):
-    """An exception that records an error message and a return value
-    """
-    def __init__(self, msg = '', rval = 1):
-        self.msg = msg
-        self.rval = rval
-
-    def __str__(self):
-        return self.msg
-
-
 class ReplicaConfig:
     def __init__(self):
         self.realm_name = ""
@@ -639,65 +629,65 @@ def run_script(main_function, operation_name, log_file_name=None,
             sys.exit(return_value)
 
     except BaseException, error:
-        handle_error(error, log_file_name)
+        message, exitcode = handle_error(error, log_file_name)
+        if message:
+            print >> sys.stderr, message
+        sys.exit(exitcode)
 
 
 def handle_error(error, log_file_name=None):
-    """Handle specific errors"""
+    """Handle specific errors. Returns a message and return code"""
 
     if isinstance(error, SystemExit):
-        sys.exit(error)
+        if isinstance(error.code, int):
+            return None, error.code
+        elif error.code is None:
+            return None, 0
+        else:
+            return str(error), 1
     if isinstance(error, RuntimeError):
-        sys.exit(error)
+        return str(error), 1
     if isinstance(error, KeyboardInterrupt):
-        print >> sys.stderr, "Cancelled."
-        sys.exit(1)
+        return "Cancelled.", 1
 
-    if isinstance(error, ScriptError):
-        if error.msg:
-            print >> sys.stderr, error.msg
-        sys.exit(error.rval)
+    if isinstance(error, admintool.ScriptError):
+        return error.msg, error.rval
 
     if isinstance(error, socket.error):
-        print >> sys.stderr, error
-        sys.exit(1)
+        return error, 1
 
     if isinstance(error, ldap.INVALID_CREDENTIALS):
-        print >> sys.stderr, "Invalid password"
-        sys.exit(1)
+        return "Invalid password", 1
     if isinstance(error, ldap.INSUFFICIENT_ACCESS):
-        print >> sys.stderr, "Insufficient access"
-        sys.exit(1)
+        return "Insufficient access", 1
     if isinstance(error, ldap.LOCAL_ERROR):
-        print >> sys.stderr, error.args[0]['info']
-        sys.exit(1)
+        return error.args[0]['info'], 1
     if isinstance(error, ldap.SERVER_DOWN):
-        print >> sys.stderr, error.args[0]['desc']
-        sys.exit(1)
+        return error.args[0]['desc'], 1
     if isinstance(error, ldap.LDAPError):
-        print >> sys.stderr, 'LDAP error: %s' % type(error).__name__
-        print >> sys.stderr, error.args[0]['info']
-        sys.exit(1)
+        return 'LDAP error: %s\n%s' % (
+            type(error).__name__, error.args[0]['info']), 1
 
     if isinstance(error, config.IPAConfigError):
-        print >> sys.stderr, "An IPA server to update cannot be found. Has one been configured yet?"
-        print >> sys.stderr, "The error was: %s" % error
-        sys.exit(1)
+        message = "An IPA server to update cannot be found. Has one been configured yet?"
+        message += "\nThe error was: %s" % error
+        return message, 1
     if isinstance(error, errors.LDAPError):
-        print >> sys.stderr, "An error occurred while performing operations: %s" % error
-        sys.exit(1)
+        return "An error occurred while performing operations: %s" % error, 1
 
     if isinstance(error, HostnameLocalhost):
-        print >> sys.stderr, "The hostname resolves to the localhost address (127.0.0.1/::1)"
-        print >> sys.stderr, "Please change your /etc/hosts file so that the hostname"
-        print >> sys.stderr, "resolves to the ip address of your network interface."
-        print >> sys.stderr, ""
-        print >> sys.stderr, "Please fix your /etc/hosts file and restart the setup program"
-        sys.exit(1)
+        message = textwrap.dedent("""
+            The hostname resolves to the localhost address (127.0.0.1/::1)
+            Please change your /etc/hosts file so that the hostname
+            resolves to the ip address of your network interface.
+
+            Please fix your /etc/hosts file and restart the setup program
+            """).strip()
+        return message, 1
 
     if log_file_name:
-        print >> sys.stderr, "Unexpected error - see %s for details:" % log_file_name
+        message = "Unexpected error - see %s for details:" % log_file_name
     else:
-        print >> sys.stderr, "Unexpected error"
-    print >> sys.stderr, '%s: %s' % (type(error).__name__, error)
-    sys.exit(1)
+        message = "Unexpected error"
+    message += '\n%s: %s' % (type(error).__name__, error)
+    return message, 1