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Posted to dev@tomcat.apache.org by co...@apache.org on 2001/02/01 06:06:06 UTC
cvs commit: jakarta-tomcat/src/share/org/apache/tomcat/core Context.java ContextManager.java
costin 01/01/31 21:06:05
Modified: src/share/org/apache/tomcat/core Context.java
ContextManager.java
Log:
The first significant change in core for this year :-)
The startup rules for tomcat were almost undefined in tomcat 3.2 and before,
and defining a clear state was one of the biggest issues for 3.3.
Things has improved ( thanks to Larry and Nacho for all the feedback),
but I don't think they are perfect yet
This is one of the biggest things that need review and attention.
This fix tightens up a bit more the startup process:
- no addContext or initContext hook can be called before the server is
fully configure ( i.e. in STATE_CONFIG ). Because the server.xml reader
adds both modules and contexts, calling addContext is delayed until
init()
- make clear that after init(), the server is fully configured and initialized
engineStart is mostly for connectors.
- reorganized a bit the documentation - runtime configuration is a different
issue.
Please read at least the ContextManager comments on the top, and send
any feedback.
( ContextManager has 1 very important role - call the hooks that
compose tomcat. It also stores global config, modules and contexts -
but that's easy )
Revision Changes Path
1.134 +1 -1 jakarta-tomcat/src/share/org/apache/tomcat/core/Context.java
Index: Context.java
===================================================================
RCS file: /home/cvs/jakarta-tomcat/src/share/org/apache/tomcat/core/Context.java,v
retrieving revision 1.133
retrieving revision 1.134
diff -u -r1.133 -r1.134
--- Context.java 2001/01/28 19:49:19 1.133
+++ Context.java 2001/02/01 05:06:04 1.134
@@ -525,7 +525,7 @@
// no action if ContextManager is not initialized
if( contextM==null ||
- contextM.getState() == ContextManager.STATE_CONFIG ) {
+ contextM.getState() == ContextManager.STATE_NEW ) {
log( "ContextManager is not yet initialized ");
return;
}
1.164 +193 -116 jakarta-tomcat/src/share/org/apache/tomcat/core/ContextManager.java
Index: ContextManager.java
===================================================================
RCS file: /home/cvs/jakarta-tomcat/src/share/org/apache/tomcat/core/ContextManager.java,v
retrieving revision 1.163
retrieving revision 1.164
diff -u -r1.163 -r1.164
--- ContextManager.java 2001/01/01 00:17:23 1.163
+++ ContextManager.java 2001/02/01 05:06:04 1.164
@@ -67,65 +67,78 @@
/**
- ContextManager is the entry point and "controler" of the servlet execution.
+ ContextManager controls requests processing and server configuration.
It maintains a list of Contexts ( web applications ) and a list of
- interceptors (hooks) that are set up to handle the actual execution.
+ global modules that deal with server configuration and request processing,
+ and global properties ( directories, general settings, etc ).
- The execution is modeled after Apache2.0 and other web servers, with
- interceptors serving the same role as modules.
-
- The "core" is composed of representation of "Request", "Response",
- "Container" ( a set of URLs with shared properties - like a Location
- in Apache), "Context" ( web application - the deployment unit ).
-
- "ContextManager" will store properties that are global to the servlet
- container - like root directory, install dir, work dir and act as the
- top level controler.
+ The request processing is similar with Apache and other servers, with the
+ addition of a "contextMap" chain that will select a tomcat-specific.
- The server functionality is implemented in modules ( "BaseInterceptor" ).
-
- Hooks are provided for request parsing and mapping, auth, autorization,
- pre/post service, actual invocation and logging - similar with Apache and all
- other web servers.
-
- <h2>Using tomcat</h2>
+ <h2>Configuration and startup</h2>
+ Starting tomcat involves a number of actions and states. In order to
+ start tomcat:
+
<ol>
- <li> Create ContextManager.
+ <li> Create ContextManager. The server state is STATE_NEW
<li> Set properties for ContextManager ( home, debug, etc).
- <li> Add the initial set of modules. Modules can also be added and removed
- after the server is started. ( engineInit() and addInterceptor() hooks
- will be called ). An interceptor can add/remove other interceptors
- during the engineInit hook, or change/set server properties.
- XXX web applications should be added at a later stage.
-
- <li> Add the initial set of web applications ( Contexts ). Applications can
- be added and removed after the server is started. ( addContext() hook
- will be called )
-
- <li>init(). All contexts will be ready to run ( contextInit() hook is called)
-
- <li>start(). engineStart() hook will be called, the connector modules
- should accept and serve requests.
-
- <li>While tomcat is running, you can add/remove interceptors ( you must
- insure the server is temporarily stoped ). engineInit(), addInterceptor()
- will be called, then addContext() for all existing contexts and
- initContext() if server is in INIT state.
-
- <li>While tomcat is running, you can temporarily disable web applications,
- remove and add new applications. If an application is disabled you can
- add local modules, that will affect only that application. Modules can
- also add and remove webapplications automatically ( like ~user ).
+ <li> Add the initial set of modules ( addInterceptor() ). ContextManager
+ will call setContextManager() and then the addInterceptor() hook.
- <li>stop() will stop the server ( engineStop() hook will be called )
+ <li> Add the initial set of web applications ( Contexts ). Configuration
+ modules can also add web applications - but no "addContext" hook
+ will be called ( since the server is not initialized ).
+
+ <li> Call init().
+ <ol>
+ <li>Init will notify all modules using the engineInit() hook. At
+ this point the ContextManager will be in STATE_CONFIG.
+ <li>It'll then call addContext() hooks for each context that were
+ added by config modules. Contexts will be in STATE_ADDED.
+ <li>It'll then call context.init() hooks for each context that were
+ added by config modules. Contexts will be in STATE_READY.
+ <li>After all contexts are added and initialized, server will be
+ in STATE_INIT.
+ </ol>
+ XXX Do we need finer control ? ( like initModules(), initContexts() ? )
+
+ <li> At this point the server is fully configured, but not started.
+ The user can add/remove modules and applications - the rules are
+ defined in "run-time configuration".
+
+ <li> Call start(). The engineStart() hook will be called,
+ the connector modules should accept and serve requests.
+
+ <li> Call stop() to stop the server ( engineStop() hook will be called,
+ no requests more will be accepted )
+
+ <li> Call shutdown() to clean up all resources in use by web applications
+ and modules. The server will revert to STATE_CONFIG.
+ <ol>
+ <li>contextShutdown() will be called for each application. Modules
+ must clean any resources allocated for that context.
- <li>shutdown() will clean up all resources in use by web applications
- ( contextShutdown() ) and remove all contexts ( removeContext() hook )
+ <li>removeContext() will be called for each application.
+
+ <li>engineShutdown() will be called for each module
+ </ol>
+
</ol>
+
+ <h2>Runtime configuration</h2>
+
+ XXX The only "supported" feature is adding/removing web applications.
+ Since each module can have a set of local modules, you can change the
+ configuration or modules for each context. Changing "global" modules may
+ work, but it's not finalized or tested.
+
+ While tomcat is running, you can temporarily disable web applications,
+ remove and add new applications.
+
@author James Duncan Davidson [duncan@eng.sun.com]
@author James Todd [gonzo@eng.sun.com]
@author Harish Prabandham
@@ -148,33 +161,27 @@
/**
* Server is beeing configured - modules are added.
- * This is the inital state. As soon as init() is called or the
- * first context is added the server will move to init state.
*/
- public static final int STATE_CONFIG=0;
+ public static final int STATE_NEW=0;
/**
- * Server is initialized, web applications can be added.
+ * Server and global modules are initialized and stable.
*/
- public static final int STATE_INIT=1;
-
+ public static final int STATE_CONFIG=1;
+
/**
- * Server is able to run requests.
+ * Web applications are configured and initialized.
*/
- public static final int STATE_START=2;
-
- /** Engine is stoped ( temporarily disabled ).
+ public static final int STATE_INIT=2;
+
+ /**
+ * Server is started and may process requests.
*/
- public static final int STATE_STOP=3;
+ public static final int STATE_START=3;
- /** Engine is shutdown. This is the final state, modules should clean
- up all resources.
- */
- public static final int STATE_SHUTDOWN=4;
-
// -------------------- local variables --------------------
- private int state=STATE_CONFIG;
+ private int state=STATE_NEW;
// All contexts managed by the server ( can belong to different
// virtual hosts )
@@ -363,49 +370,78 @@
defaultContainer = newDefaultContainer;
}
- /** Add a global interceptor. It's hooks will be called for
- * all requests.
+ /** Add a global interceptor. The addInterceptor() hook will be called.
+ * If the module is added after STATE_CONFIG, the engineInit() hook will
+ * be called ( otherwise we wait for init() ).
+ * If the module is added after STATE_INIT, the addContext and
+ * initContext hooks will be called.
+ * If the module is added after STATE_START, the engineStart hooks will
+ * be called.
*/
public final void addInterceptor( BaseInterceptor ri )
throws TomcatException
{
ri.setContextManager( this );
+ // first, add the module ( addInterceptor may change the ordering )
+ defaultContainer.addInterceptor(ri);
+
+ // second, let the module know it's added. It may look at
+ // other module and even choose to remove himself and throw exception.
+ ri.addInterceptor( this, null, ri ); // should know about itself
+
+ // let other modules know about the new friend.
BaseInterceptor existingI[]=defaultContainer.getInterceptors();
for( int i=0; i<existingI.length; i++ ) {
- existingI[i].addInterceptor( this, null, ri );
+ if( existingI[i] != ri )
+ existingI[i].addInterceptor( this, null, ri );
}
- ri.addInterceptor( this, null, ri ); // should know about itself
- defaultContainer.addInterceptor(ri);
-
- if( state==STATE_CONFIG ) return;
+ // startup module, server is not initialized
+ if( state==STATE_NEW ) return;
- // we are at last initialized, call engineInit hook
+ // we are at last initialized, call engineInit hook ( a module
+ // at runtime will get the same calls as a setup module )
ri.engineInit( this );
- // make sure the interceptor knows about all existing contexts.
+ if( state== STATE_CONFIG ) return;
+
+ // addContext hook for all existing contexts
Enumeration enum = getContexts();
while (enum.hasMoreElements()) {
Context ctx = (Context)enum.nextElement();
try {
ri.addContext( this, ctx );
- if( state==STATE_START ) {
- ri.contextInit( ctx );
- }
} catch( TomcatException ex ) {
+ log( "Error adding context " +ctx + " to " + ri ); // ignore
+ }
+ }
+
+ // contextInit hook if we're started
+ enum = getContexts();
+ while (enum.hasMoreElements()) {
+ Context ctx = (Context)enum.nextElement();
+ try {
+ ri.contextInit( ctx );
+ } catch( TomcatException ex ) {
log( "Error adding context " +ctx + " to " + ri );
- // ignore it
+ // ignore it
}
}
- if( state==STATE_START )
- ri.engineStart(this);
+ if( state==STATE_INIT ) return;
+
+ // we are running - let the module know about that.
+ ri.engineStart(this);
}
+ /** Remove a module. Hooks will be called to allow the module to
+ * free the resources.
+ */
public final void removeInterceptor( BaseInterceptor ri )
throws TomcatException
{
+
BaseInterceptor existingI[]=defaultContainer.getInterceptors();
for( int i=0; i<existingI.length; i++ ) {
existingI[i].removeInterceptor( this, null, ri );
@@ -414,24 +450,35 @@
defaultContainer.removeInterceptor( ri );
- if( state==STATE_CONFIG ) return;
-
- Enumeration enum = getContexts();
- while (enum.hasMoreElements()) {
- Context ctx = (Context)enum.nextElement();
- try {
- if( state==STATE_START ) {
+ if( state==STATE_NEW ) return;
+
+ if( state==STATE_START )
+ ri.engineStop(this);
+
+ if( state >= STATE_INIT ) {
+ Enumeration enum = getContexts();
+ while (enum.hasMoreElements()) {
+ Context ctx = (Context)enum.nextElement();
+ try {
ri.contextShutdown( ctx );
+ } catch( TomcatException ex ) {
+ log( "Error shuting down context " +ctx + " to " + ri );
}
- ri.removeContext( this, ctx );
- } catch( TomcatException ex ) {
- log( "Error adding context " +ctx + " to " + ri );
- // ignore it
}
+
+ enum = getContexts();
+ while (enum.hasMoreElements()) {
+ Context ctx = (Context)enum.nextElement();
+ try {
+ ri.removeContext( this, ctx );
+ } catch( TomcatException ex ) {
+ log( "Error removing context " +ctx + " to " + ri );
+ // ignore it
+ }
+ }
}
- if( state==STATE_START )
- ri.engineStop(this);
+ ri.engineShutdown( this );
}
// -------------------- Server functions --------------------
@@ -445,42 +492,60 @@
*
*/
public final void init() throws TomcatException {
- if( state == STATE_INIT )
+ if( state >= STATE_CONFIG ) // already initialized
return;
- if(debug>0 ) log( "Tomcat init");
- setState(STATE_INIT);
+ if(debug>0 ) log( "Tomcat init");
BaseInterceptor existingI[]=defaultContainer.getInterceptors();
for( int i=0; i<existingI.length; i++ ) {
existingI[i].engineInit( this );
}
- }
+ // The server is configured, all modules are ready
+ setState(STATE_CONFIG);
- /** Will start the connectors and begin serving requests.
- * It must be called after init.
- */
- public final void start() throws TomcatException {
- if( state==STATE_CONFIG ) {
- init();
+ // deal with contexts that were added before init()
+ // ( by user or modules during engineInit )
+ Enumeration enum = getContexts();
+ while (enum.hasMoreElements()) {
+ Context ctx = (Context)enum.nextElement();
+ try {
+ for( int i=0; i<existingI.length; i++ ) {
+ existingI[i].addContext( this, ctx );
+ }
+ ctx.setState( Context.STATE_ADDED );
+ log("Adding context " + ctx.toString());
+ } catch( TomcatException ex ) {
+ log( "Error adding context " + ctx , ex );
+ continue;
+ }
}
- // make sure all context are ready
- Enumeration enum = getContexts();
+ // Initialize the contexts
+ enum = getContexts();
while (enum.hasMoreElements()) {
Context ctx = (Context)enum.nextElement();
try {
ctx.init();
} catch( TomcatException ex ) {
- // just log the error, the context will not serve
- // requests but we go on
+ // just log the error - the context will not serve requests
log( "Error initializing " + ctx , ex );
continue;
}
}
- //XXX before or after state=START ?
+ setState( STATE_INIT );
+ }
+
+ /** Will start the connectors and begin serving requests.
+ * It must be called after init.
+ */
+ public final void start() throws TomcatException {
+ if( state==STATE_NEW ) {
+ init();
+ }
+
BaseInterceptor cI[]=defaultContainer.getInterceptors();
for( int i=0; i< cI.length; i++ ) {
cI[i].engineStart( this );
@@ -515,7 +580,7 @@
BaseInterceptor cI[]=defaultContainer.getInterceptors();
for( int i=0; i< cI.length; i++ ) {
- cI[i].engineShutdown( this );
+ removeInterceptor( cI[i] );
}
}
@@ -534,19 +599,14 @@
/**
* Adds a new Context to the set managed by this ContextManager.
- *
- * If the server is initialized ( ContextManager.init() was called )
- * the addContext() hook will be called, otherwise the call will
- * be delayed until the server enters INIT state.
+ * It'll also init the server if it hasn't been already.
*
- * The context will be in DISABLED state until start() is called.
+ * All addContext hooks will be called. The context will be
+ * in STATE_ADDED - it'll not serve requests.
*
* @param ctx context to be added.
*/
public final void addContext( Context ctx ) throws TomcatException {
- if( state==STATE_CONFIG) {
- init();
- }
// Make sure context knows about its manager.
// this will also initialized all context-specific modules.
ctx.setContextManager( this );
@@ -554,6 +614,10 @@
contextsV.addElement( ctx );
+ if( getState() == STATE_NEW )
+ return;
+
+ // we are at least configured, can call the hook
try {
BaseInterceptor cI[]=ctx.getContainer().getInterceptors();
for( int i=0; i< cI.length; i++ ) {
@@ -579,6 +643,11 @@
contextsV.removeElement(context);
+ if( getState() == STATE_NEW )
+ return; // we are not even initialized
+ // modules can add/remove contexts at init time, but no
+ // action will take place until the server is stable.
+
// if it's already disabled - or was never activated,
// no need to shutdown and remove
if( context.getState() == Context.STATE_NEW )
@@ -734,6 +803,14 @@
if( status!=0 ) return status;
}
req.setState(Request.STATE_CONTEXT_MAPPED );
+
+ if( req.getContext() == null ||
+ req.getContext().getState() != Context.STATE_READY ) {
+ // the context is not fully initialized.
+ req.setAttribute("javax.servlet.error.message",
+ "Application not available");
+ handleStatus( req, req.getResponse(), 503 ); // service unavailable
+ }
ri=defaultContainer.getInterceptors(Container.H_requestMap);
for( int i=0; i< ri.length; i++ ) {