[Pki-devel] [PATCH] pki-ftweedal-0015-Monitor-database-for-changes-to-LDAP-profiles.patch

Fraser Tweedale ftweedal at redhat.com
Thu Nov 20 06:32:41 UTC 2014


Thanks Endi, you picked up several subtle problems in your review.
I addressed all the issues in the new patch (attached).

Fraser

On Thu, Oct 09, 2014 at 09:47:29AM -0500, Endi Sukma Dewata wrote:
> On 10/1/2014 1:42 AM, Fraser Tweedale wrote:
> >On Mon, Sep 22, 2014 at 05:36:26PM +1000, Fraser Tweedale wrote:
> >>This is the first cut of the LDAP profile change monitoring.  It
> >>depends on patches 0004..0009 and 0014
> >>(https://www.redhat.com/archives/pki-devel/2014-September/msg00052.html).
> >>
> >>To summarise the implementation: a separate thread carries out a
> >>persistent LDAP search and calls back into the ProfileSubsystem when
> >>changes occur.  I haven't had much experience with persistent
> >>searches or multithreaded programming in Java, so eyeballs familiar
> >>with those areas are needed.
> >>
> >>I haven't yet tested with changes replicating between clones (a task
> >>for tomorrow) but I wanted to get the patch on list for feedback as
> >>early as possible.
> >>
> >Further to earlier email, I tested profile change replication
> >between clones and it is working well.
> >
> 
> Some comments:
> 
> 1. The MODDN operation can potentially happen if someone renames the profile
> in LDAP directly, and that's easier to do with LDAP-based profiles. I think
> we should handle this case too.
> 
> 2. If the LDAP server is restarted the Monitor will stop working and
> subsequent changes are not detected. The Monitor should automatically
> reconnect in case the LDAP connection is interrupted.
> 
> 3. Since the changesOnly is set to true, there's a possibility that changes
> that happens after initial profile loading and before the Monitor starts
> will not be detected. To avoid this problem, the changesOnly should be
> false, and the initial profile loading should be done in the Monitor as
> well.
> 
> 4. The following assignment is redundant because the value is overwritten by
> the next line:
> 
>     String profileId = "<unknown>";
> 
> 5. When receiving a MODIFY operation the Monitor calls forgetProfile(). It's
> probably redundant because readProfile() calls createProfile() which calls
> forgetProfile() too.
> 
> 6. Generally it's recommended to implement Runnable instead of extending
> Thread. The Monitor can be merged into ProfileSubsystem.
> 
> I think #1, #2, #3 are important to fix because there is no mechanism to
> refresh the profiles in memory other than by restarting the server, so we
> cannot miss any changes in the database.
> 
> 
> -- 
> Endi S. Dewata
-------------- next part --------------
>From 518841c8527c57f45b1b434685dd0b7276f4f366 Mon Sep 17 00:00:00 2001
From: Fraser Tweedale <ftweedal at redhat.com>
Date: Mon, 22 Sep 2014 03:22:57 -0400
Subject: [PATCH 10/10] Monitor database for changes to LDAP profiles.

Use a persistent query to monitor the database for changes to LDAP
profiles, and update the contents of the ProfileSubsystem according
to the changes (Add/Modify/Delete) that occur.

The monitoring occurs within its own thread.
---
 .../netscape/cmscore/profile/ProfileSubsystem.java | 207 ++++++++++++++++-----
 1 file changed, 160 insertions(+), 47 deletions(-)

diff --git a/base/server/cmscore/src/com/netscape/cmscore/profile/ProfileSubsystem.java b/base/server/cmscore/src/com/netscape/cmscore/profile/ProfileSubsystem.java
index ca0e09b785877da2a98fd2dd54977b8d3ebeaa24..2318fcf997801e3a729a7dab7caad3dce182486b 100644
--- a/base/server/cmscore/src/com/netscape/cmscore/profile/ProfileSubsystem.java
+++ b/base/server/cmscore/src/com/netscape/cmscore/profile/ProfileSubsystem.java
@@ -17,15 +17,21 @@
 // --- END COPYRIGHT BLOCK ---
 package com.netscape.cmscore.profile;
 
+import java.lang.Thread;
 import java.util.Enumeration;
 import java.util.Hashtable;
 import java.util.Vector;
 
 import netscape.ldap.LDAPAttribute;
 import netscape.ldap.LDAPConnection;
+import netscape.ldap.LDAPControl;
 import netscape.ldap.LDAPEntry;
 import netscape.ldap.LDAPException;
+import netscape.ldap.LDAPSearchConstraints;
 import netscape.ldap.LDAPSearchResults;
+import netscape.ldap.controls.LDAPEntryChangeControl;
+import netscape.ldap.controls.LDAPPersistSearchControl;
+import netscape.ldap.util.DN;
 
 import com.netscape.certsrv.apps.CMS;
 import com.netscape.certsrv.base.EBaseException;
@@ -40,7 +46,7 @@ import com.netscape.certsrv.registry.IPluginInfo;
 import com.netscape.certsrv.registry.IPluginRegistry;
 import com.netscape.cmscore.base.LDAPConfigStore;
 
-public class ProfileSubsystem implements IProfileSubsystem {
+public class ProfileSubsystem implements IProfileSubsystem, Runnable {
     private static final String PROP_CHECK_OWNER = "checkOwner";
 
     private static final String PROP_ENABLE = "enable";
@@ -52,9 +58,13 @@ public class ProfileSubsystem implements IProfileSubsystem {
     private Vector<String> mProfileIds;
     private Hashtable<String, IProfile> mProfiles;
     private Hashtable<String, String> mProfileClassIds;
+    private String dn;
 
     private ILdapConnFactory dbFactory;
 
+    private boolean stopped = false;
+    private Thread monitor;
+
     /**
      * Retrieves the name of this subsystem.
      */
@@ -86,9 +96,6 @@ public class ProfileSubsystem implements IProfileSubsystem {
         mProfiles = new Hashtable<String, IProfile>();
         mProfileClassIds = new Hashtable<String, String>();
 
-        IPluginRegistry registry = (IPluginRegistry)
-                CMS.getSubsystem(CMS.SUBSYSTEM_REGISTRY);
-
         IConfigStore cs = CMS.getConfigStore();
         IConfigStore dbCfg = cs.getSubStore("internaldb");
         dbFactory = CMS.getLdapBoundConnFactory();
@@ -106,60 +113,47 @@ public class ProfileSubsystem implements IProfileSubsystem {
 
         // read profile id, implementation, and its configuration files
         String basedn = cs.getString("internaldb.basedn");
-        String dn = "ou=certificateProfiles,ou=ca," + basedn;
-        LDAPConnection conn = dbFactory.getConn();
+        dn = "ou=certificateProfiles,ou=ca," + basedn;
 
-        String[] attrs = {"cn", "classId"};
-        try {
-            LDAPSearchResults ldapProfiles = conn.search(
-                dn, LDAPConnection.SCOPE_ONE, "(objectclass=*)", attrs, false);
+        monitor = new Thread(this, "profileChangeMonitor");
+        monitor.start();
+    }
 
-            while (ldapProfiles.hasMoreElements()) {
-                String id = "<unknown>";
-                try {
-                    LDAPEntry ldapProfile = ldapProfiles.next();
+    /**
+     * Read the given LDAPEntry into the profile subsystem.
+     */
+    private void readProfile(LDAPEntry ldapProfile) {
+        IPluginRegistry registry = (IPluginRegistry)
+            CMS.getSubsystem(CMS.SUBSYSTEM_REGISTRY);
 
-                    id = (String)
-                        ldapProfile.getAttribute("cn").getStringValues().nextElement();
+        String profileId = (String)
+            ldapProfile.getAttribute("cn").getStringValues().nextElement();
 
-                    String classid = (String)
-                        ldapProfile.getAttribute("classId").getStringValues().nextElement();
+        String classId = (String)
+            ldapProfile.getAttribute("classId").getStringValues().nextElement();
 
-                    IPluginInfo info = registry.getPluginInfo("profile", classid);
-                    if (info == null) {
-                        CMS.debug("Error loading profile: No plugins for type : profile, with id " + classid);
-                    } else {
-                        CMS.debug("Start Profile Creation - " + id + " " + classid + " " + info.getClassName());
-                        createProfile(id, classid, info.getClassName());
-                        CMS.debug("Done Profile Creation - " + id);
-                    }
-                } catch (LDAPException e) {
-                    CMS.debug("Error reading profile '" + id + "'; skipping.");
-                }
-            }
-        } catch (LDAPException e) {
-            throw new EBaseException("Error reading profiles: " + e.toString());
-        } finally {
+        IPluginInfo info = registry.getPluginInfo("profile", classId);
+        if (info == null) {
+            CMS.debug("Error loading profile: No plugins for type : profile, with classId " + classId);
+        } else {
             try {
-                dbFactory.returnConn(conn);
-            } catch (Exception e) {
-                throw new EProfileException("Error releasing the ldap connection" + e.toString());
+                CMS.debug("Start Profile Creation - " + profileId + " " + classId + " " + info.getClassName());
+                createProfile(profileId, classId, info.getClassName());
+                CMS.debug("Done Profile Creation - " + profileId);
+            } catch (EProfileException e) {
+                CMS.debug("Error creating profile '" + profileId + "'; skipping.");
             }
         }
-
-        Enumeration<String> ee = getProfileIds();
-
-        while (ee.hasMoreElements()) {
-            String id = ee.nextElement();
-
-            CMS.debug("Registered Confirmation - " + id);
-        }
     }
 
     /**
      * Creates a profile instance.
+     *
+     * createProfile could theoretically be called simultaneously
+     * with the same profileId from Monitor and ProfileService,
+     * so the method is synchronized.
      */
-    public IProfile createProfile(String id, String classid, String className)
+    public synchronized IProfile createProfile(String id, String classid, String className)
             throws EProfileException {
         try {
             String[] objectClasses = {"top", "certProfile"};
@@ -176,7 +170,8 @@ public class ProfileSubsystem implements IProfileSubsystem {
             IProfile profile = (IProfile) Class.forName(className).newInstance();
             profile.setId(id);
             profile.init(this, subStoreConfig);
-            mProfileIds.addElement(id);
+            if (!mProfiles.containsKey(id))
+                mProfileIds.addElement(id);
             mProfiles.put(id, profile);
             mProfileClassIds.put(id, classid);
             return profile;
@@ -211,11 +206,41 @@ public class ProfileSubsystem implements IProfileSubsystem {
             }
         }
 
+        forgetProfile(id);
+    }
+
+    private synchronized void handleMODDN(DN oldDN, LDAPEntry entry) {
+        DN profilesDN = new DN(dn);
+
+        if (oldDN.isDescendantOf(profilesDN))
+            forgetProfile(oldDN.explodeDN(true)[0]);
+
+        if ((new DN(entry.getDN())).isDescendantOf(profilesDN))
+            readProfile(entry);
+    }
+
+    /**
+     * Forget a profile without deleting it from the database.
+     *
+     * This method is used when the profile change monitor receives
+     * notification that a profile was deleted.
+     */
+    private void forgetProfile(String id) {
         mProfileIds.removeElement(id);
         mProfiles.remove(id);
         mProfileClassIds.remove(id);
     }
 
+    private void forgetProfile(LDAPEntry entry) {
+        String profileId = (String)
+            entry.getAttribute("cn").getStringValues().nextElement();
+        if (profileId == null) {
+            CMS.debug("forgetProfile: error retrieving cn (profileId) from LDAPEntry");
+        } else {
+            forgetProfile(profileId);
+        }
+    }
+
     /**
      * Notifies this subsystem if owner is in running mode.
      */
@@ -229,6 +254,8 @@ public class ProfileSubsystem implements IProfileSubsystem {
      * <P>
      */
     public void shutdown() {
+        stopped = true;
+        monitor = null;
         mProfileIds.clear();
         mProfiles.clear();
         mProfileClassIds.clear();
@@ -346,6 +373,92 @@ public class ProfileSubsystem implements IProfileSubsystem {
         } catch (EBaseException e) {
             throw new EProfileException("CMS_PROFILE_DELETE_UNKNOWNPROFILE");
         }
-        return "cn=" + id + ",ou=certificateProfiles,ou=ca," + basedn;
+        return "cn=" + id + "," + dn;
+    }
+
+    public void run() {
+        int op = LDAPPersistSearchControl.ADD
+            | LDAPPersistSearchControl.MODIFY
+            | LDAPPersistSearchControl.DELETE
+            | LDAPPersistSearchControl.MODDN;
+        LDAPPersistSearchControl persistCtrl =
+            new LDAPPersistSearchControl(op, false, true, true);
+
+        LDAPConnection conn;
+
+        CMS.debug("Profile change monitor: starting.");
+
+        while (!stopped) {
+            try {
+                conn = dbFactory.getConn();
+            } catch (ELdapException e) {
+                CMS.debug("Profile change monitor: failed to get LDAPConnection. Retrying in 5 seconds.");
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException ex) {
+                    Thread.currentThread().interrupt();
+                }
+                continue;
+            }
+            try {
+                LDAPSearchConstraints cons = conn.getSearchConstraints();
+                cons.setServerControls(persistCtrl);
+                cons.setBatchSize(1);
+                cons.setServerTimeLimit(0 /* seconds */);
+                LDAPSearchResults results = conn.search(
+                    dn, LDAPConnection.SCOPE_ONE, "(objectclass=*)",
+                    null, false, cons);
+                while (!stopped && results.hasMoreElements()) {
+                    LDAPEntry entry = results.next();
+                    LDAPEntryChangeControl changeControl = null;
+                    LDAPControl[] changeControls = results.getResponseControls();
+                    if (changeControls != null) {
+                        for (LDAPControl control : changeControls) {
+                            if (control instanceof LDAPEntryChangeControl) {
+                                changeControl = (LDAPEntryChangeControl) control;
+                                break;
+                            }
+                        }
+                    }
+                    CMS.debug("Profile change monitor: Processed change controls.");
+                    if (changeControl != null) {
+                        int changeType = changeControl.getChangeType();
+                        switch (changeType) {
+                        case LDAPPersistSearchControl.ADD:
+                            CMS.debug("Profile change monitor: ADD");
+                            readProfile(entry);
+                            break;
+                        case LDAPPersistSearchControl.DELETE:
+                            CMS.debug("Profile change monitor: DELETE");
+                            forgetProfile(entry);
+                            break;
+                        case LDAPPersistSearchControl.MODIFY:
+                            CMS.debug("Profile change monitor: MODIFY");
+                            readProfile(entry);
+                            break;
+                        case LDAPPersistSearchControl.MODDN:
+                            CMS.debug("Profile change monitor: MODDN");
+                            handleMODDN(new DN(changeControl.getPreviousDN()), entry);
+                            break;
+                        default:
+                            CMS.debug("Profile change monitor: unknown change type: " + changeType);
+                            break;
+                        }
+                    } else {
+                        CMS.debug("Profile change monitor: immediate result");
+                        readProfile(entry);
+                    }
+                }
+            } catch (LDAPException e) {
+                CMS.debug("Profile change monitor: Caught exception: " + e.toString());
+            } finally {
+                try {
+                    dbFactory.returnConn(conn);
+                } catch (Exception e) {
+                    CMS.debug("Profile change monitor: Error releasing the LDAPConnection" + e.toString());
+                }
+            }
+        }
+        CMS.debug("Profile change monitor: stopping.");
     }
 }
-- 
1.9.3



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