server/componentmanager/ComponentManager.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

//---PACKAGE DECLARATION---
package uk.org.iscream.cms.server.componentmanager;

//---IMPORTS---
import java.util.*;
import java.io.*;
import uk.org.iscream.cms.util.*;

/**
 * The component manager is the starting point for all
 * server side components of the iscream system.
 * It loads its initial system configuration from the
 * default properties file, it then starts all the iscream
 * components as specified in the default.properties under
 * uk.org.iscream.cms.server.ComponentList
 *
 * @author  $Author: tdb $
 * @version $Id: ComponentManager.java,v 1.41 2002/05/21 16:47:17 tdb Exp $
 */
public class ComponentManager {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.41 $";
    
    /**
     * The toString() of this class
     * As it won't be instatiated, this is needed.
     * Not also that we pass a null as the class name (as we are static)
     */
    public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
    
    /**
     * The default location of the properties file for the system
     */
    public static final String DEFAULTPROPERTIES = "./etc/default.properties";
    
    /**
     * The default time to wait before retrying 
     * component.
     */
    public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
    
//---STATIC METHODS---

    /**
     * The main method which starts the components as
     * listed in the default.properties file.
     *
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        System.out.println("-----------------------------------------");
        System.out.println("--- i-scream Server Component Manager ---");
        System.out.println("---   (c) 2001 The i-scream Project   ---");
        System.out.println("---    (http://www.i-scream.org.uk)   ---");
        System.out.println("-----------------------------------------");
        System.out.println("---          Starting System          ---");        
        
        // get the command line args
        String defaultProperties = DEFAULTPROPERTIES;
        String filterName = null;
        String filterManagerName = null;
        for(int i=0; i < args.length; i++) {
            if(args[i].equals("-h")) {
                usage();
            }
            else if(args[i].equals("-f")) {
                if(++i < args.length) {
                    filterName = args[i];
                }
                else {
                    usage();
                }
            }
            else if(args[i].equals("-fm")) {
                if(++i < args.length) {
                    filterManagerName = args[i];
                }
                else {
                    usage();
                }
            }
            else if(args[i].equals("-l")) {
                if(++i < args.length) {
                    defaultProperties = args[i];
                }
                else {
                    usage();
                }
            }
            else {
                usage();
            }
        }

        // load the default properties file into the system properties
        System.out.println(toString + ": initialising - using " + defaultProperties);
        try {
            Properties initProperties = new Properties(System.getProperties());
            initProperties.load(new FileInputStream(new File(defaultProperties)));
            System.setProperties(initProperties);
        } catch (Exception e) {
            System.err.println(toString + ": ERROR " + e.getMessage());
            usage();
        }

        // continue to bring the system up
        System.out.println(toString + ": coming up");
        
        // start the ORB by initialising the ReferenceManager
        ReferenceManager refman = ReferenceManager.getInstance();
        
        // now the ORB is running, we need to activate our RootPOA
        // so that we can start serving requests once servants start up
        refman.activatePOA();
        
        // get the list of components
        String componentList = System.getProperty("uk.org.iscream.cms.server.ComponentList");
        StringTokenizer st = new StringTokenizer(componentList, ";");
        _componentsToStart = new LinkedList();
        
        // this could be done using reflection
        // but..well..we don't ;-p
        while (st.hasMoreTokens()){
            String componentName = st.nextToken();
            Component component = null;
            
            
            // ### This is where the list of supported components is checked! ###
            if (componentName.equalsIgnoreCase("core")) {
                component = new uk.org.iscream.cms.server.core.Core();
            // note the passing of the FilterManagers's name in its constructor
            } else if (componentName.equalsIgnoreCase("filtermanager")) {
                component = new uk.org.iscream.cms.server.filtermanager.FilterManager(filterManagerName);
            } else if (componentName.equalsIgnoreCase("rootfilter")) {
                component = new uk.org.iscream.cms.server.rootfilter.RootFilter();
            } else if (componentName.equalsIgnoreCase("dbinterface")) {
                component = new uk.org.iscream.cms.server.dbinterface.DBInterface();
            } else if (componentName.equalsIgnoreCase("clientinterface")) {
                component = new uk.org.iscream.cms.server.clientinterface.ClientInterfaceMain();
            // note the passing of the Filter's name in its constructor
            } else if (componentName.equalsIgnoreCase("filter")) {
                component = new uk.org.iscream.cms.server.filter.FilterMain(filterName);
            } else if (componentName.equalsIgnoreCase("client")) {
                component = new uk.org.iscream.cms.server.client.ClientMain();
            }
            // ###  Add new component constructors in the above section! ###
            
            // build the list of components to start
            if (component != null) {
                _componentsToStart.add(component);    
            } else {
                System.err.println(toString + ": WARNING unsupported component not started: "+componentName);
            }
        }
        
        

        // get the value for timeout
        
        String confTimeout = null;
        try {
            confTimeout = System.getProperty("uk.org.iscream.cms.server.ComponentTimeout");
            confTimeout.trim();
            _startTimeout = Integer.parseInt(confTimeout);
        } catch (NumberFormatException e) {
            _startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
            System.err.println(toString + ": unable to read uk.org.iscream.cms.server.ComponentTimeout value (" + confTimeout + "), using default!");
        }
        System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
        
        // startup the system components
        startUp();

            // block on the ORB...in time, management functionality can be placed here.
            // if we detect a CORBA communication error, we'll restart all the components.
            // !! this doesn't appear to work !!
            while(true) {
            try {
                refman.getORB().run();
            } catch (org.omg.CORBA.COMM_FAILURE e) {
                System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
                System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
            }
            startUp();
        }
    }

    /**
     * Starts the components as obtained from the configuration.
     * This method calls the start() methods on all the components.
     * If a component fails to start due to a CORBA communication
     * problem, then it catches this and tries to start it again
     * according to uk.org.iscream.cms.server.ComponentTimeout time.
     *
     * If the server dies and CORBA connections are lost, this method
     * is called again.
     */
    private static void startUp() {
        // now we try and start the beast up        
        boolean tryAgain = true;
        Component component = null;
        
        // keep trying until we've started all the components.
        // maybe add support for a limited number of retries
        while(tryAgain) {
            Iterator i = _componentsToStart.iterator();
            LinkedList failedComponents = new LinkedList();
            // go through all the components
            while(i.hasNext()) {
                // get a refence to the component
                component = (Component) i.next();
                System.out.println(toString + ": dependency checking component - " + component.toString());
                
                // check it's dependencies
                boolean depOK = component.depCheck();
                if(depOK) {
                    System.out.println(toString + ": starting component - " + component.toString());
                    // it should be ok to start the component
                        try {    
                            // start the component
                        component.start();
                    } catch (ComponentStartException e) {
                        // if we get this then there was a problem
                        // that we can't recover from
                        System.err.println(toString + ": ERROR starting component - " + component.toString());
                        System.err.println(toString + ": component reports - " + e.getMessage());
                        System.exit(1);
                    }
                }
                else {
                    // it seems the depedencies failed
                    // so we want to try again after a delay
                    System.err.println(toString + ": WARNING Component reported dependency failure");
                    System.err.println(toString + ": This could be because it can't communicate with components it needs.");
                    
                    // make a list of the failed components
                    failedComponents.add(component);
                }
            }
            
            // if we had some failed components that we can retry
            if (failedComponents.size() > 0) {
                System.err.println(toString + ": WARNING One or more components failed to start correctly.");
                System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
            
                // our list is now the failed list
                _componentsToStart = failedComponents;
                
                // sleep for a given timeout
                try {    
                    Thread.sleep(_startTimeout * 1000);
                } catch (InterruptedException e) {
                    // we're not bothered
                }
            // otherwise we started everything
            } else {
                // so we set to exit the loop
                tryAgain = false;
            }
        }
                
            System.out.println(toString + ": running");
        }

    /**
     * A simple method to print the usage of this class.
     * It never returns, but instead exits to the system
     * with a value 1, to indicate the system did not start
     * properly.
     */
    public static void usage() {
        System.out.println("USAGE: java uk.org.iscream.cms.server.componentmanager.ComponentManager <option>");
        System.out.println("   or: java -jar iscream.jar <option>");
        System.out.println("WHERE <option>:");
        System.out.println("      -l <filename> - the location of initial system properties");
        System.out.println("                      the default is ./etc/default.properties");
        System.out.println("      -f <name>     - the name of the filter (if there is one configured");
        System.out.println("      -fm <name>    - the name of the filter manager (if there is one configured");
        System.out.println("      -h            - this help screen");
        System.exit(1);
    }

//---CONSTRUCTORS---

//---PUBLIC METHODS---

//---PRIVATE METHODS---

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---
    
//---STATIC ATTRIBUTES---

    private static LinkedList _componentsToStart;
    private static int _startTimeout = 0;

}
Revision:	1.42
Committed:	Wed Feb 5 16:43:46 2003 UTC (21 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.41:	+3 -3 lines
Log Message:	Changed the server to use the external util package. Quite a minor change, but does affect a lot of files.
#	User	Rev	Content
1	tdb	1.40	/*
2			* i-scream central monitoring system
3	tdb	1.41	* http://www.i-scream.org.uk
4	tdb	1.40	* Copyright (C) 2000-2002 i-scream
5			*
6			* This program is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU General Public License
8			* as published by the Free Software Foundation; either version 2
9			* of the License, or (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19			*/
20
21	ajm	1.1	//---PACKAGE DECLARATION---
22	tdb	1.38	package uk.org.iscream.cms.server.componentmanager;
23	ajm	1.1
24			//---IMPORTS---
25			import java.util.*;
26			import java.io.*;
27	tdb	1.42	import uk.org.iscream.cms.util.*;
28	ajm	1.1
29			/**
30	ajm	1.2	* The component manager is the starting point for all
31			* server side components of the iscream system.
32			* It loads its initial system configuration from the
33			* default properties file, it then starts all the iscream
34			* components as specified in the default.properties under
35	tdb	1.38	* uk.org.iscream.cms.server.ComponentList
36	ajm	1.1	*
37	tdb	1.39	* @author $Author: tdb $
38	tdb	1.42	* @version $Id: ComponentManager.java,v 1.41 2002/05/21 16:47:17 tdb Exp $
39	ajm	1.1	*/
40			public class ComponentManager {
41
42			//---FINAL ATTRIBUTES---
43
44			/**
45			* The current CVS revision of this class
46			*/
47	tdb	1.42	public static final String REVISION = "$Revision: 1.41 $";
48	ajm	1.1
49			/**
50			* The toString() of this class
51			* As it won't be instatiated, this is needed.
52	ajm	1.2	* Not also that we pass a null as the class name (as we are static)
53	ajm	1.1	*/
54	ajm	1.2	public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
55	ajm	1.1
56			/**
57			* The default location of the properties file for the system
58			*/
59	ajm	1.2	public static final String DEFAULTPROPERTIES = "./etc/default.properties";
60	ajm	1.1
61	ajm	1.22	/**
62			* The default time to wait before retrying
63			* component.
64			*/
65			public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
66
67	ajm	1.1	//---STATIC METHODS---
68
69			/**
70	ajm	1.2	* The main method which starts the components as
71			* listed in the default.properties file.
72	ajm	1.1	*
73			* @param args the command line arguments
74			*/
75			public static void main(String[] args) {
76	ajm	1.36	System.out.println("-----------------------------------------");
77	tdb	1.11	System.out.println("--- i-scream Server Component Manager ---");
78	tdb	1.37	System.out.println("--- (c) 2001 The i-scream Project ---");
79	ajm	1.36	System.out.println("--- (http://www.i-scream.org.uk) ---");
80			System.out.println("-----------------------------------------");
81	ajm	1.2	System.out.println("--- Starting System ---");
82
83	ajm	1.1	// get the command line args
84			String defaultProperties = DEFAULTPROPERTIES;
85			String filterName = null;
86	tdb	1.39	String filterManagerName = null;
87	tdb	1.11	for(int i=0; i < args.length; i++) {
88	tdb	1.12	if(args[i].equals("-h")) {
89	ajm	1.1	usage();
90	tdb	1.11	}
91	tdb	1.12	else if(args[i].equals("-f")) {
92	tdb	1.39	if(++i < args.length) {
93			filterName = args[i];
94			}
95			else {
96			usage();
97			}
98			}
99			else if(args[i].equals("-fm")) {
100			if(++i < args.length) {
101			filterManagerName = args[i];
102			}
103			else {
104			usage();
105			}
106	tdb	1.11	}
107	tdb	1.12	else if(args[i].equals("-l")) {
108	tdb	1.39	if(++i < args.length) {
109			defaultProperties = args[i];
110			}
111			else {
112			usage();
113			}
114	tdb	1.11	}
115			else {
116			usage();
117			}
118	ajm	1.1	}
119
120			// load the default properties file into the system properties
121			System.out.println(toString + ": initialising - using " + defaultProperties);
122			try {
123			Properties initProperties = new Properties(System.getProperties());
124			initProperties.load(new FileInputStream(new File(defaultProperties)));
125			System.setProperties(initProperties);
126			} catch (Exception e) {
127			System.err.println(toString + ": ERROR " + e.getMessage());
128			usage();
129			}
130
131			// continue to bring the system up
132			System.out.println(toString + ": coming up");
133
134			// start the ORB by initialising the ReferenceManager
135	ajm	1.2	ReferenceManager refman = ReferenceManager.getInstance();
136	ajm	1.1
137	ajm	1.2	// now the ORB is running, we need to activate our RootPOA
138			// so that we can start serving requests once servants start up
139	ajm	1.1	refman.activatePOA();
140
141	ajm	1.2	// get the list of components
142	tdb	1.38	String componentList = System.getProperty("uk.org.iscream.cms.server.ComponentList");
143	ajm	1.1	StringTokenizer st = new StringTokenizer(componentList, ";");
144	tdb	1.33	_componentsToStart = new LinkedList();
145	ajm	1.13
146	ajm	1.1	// this could be done using reflection
147			// but..well..we don't ;-p
148			while (st.hasMoreTokens()){
149			String componentName = st.nextToken();
150			Component component = null;
151	ajm	1.13
152	ajm	1.2
153			// ### This is where the list of supported components is checked! ###
154			if (componentName.equalsIgnoreCase("core")) {
155	tdb	1.38	component = new uk.org.iscream.cms.server.core.Core();
156	tdb	1.39	// note the passing of the FilterManagers's name in its constructor
157	ajm	1.3	} else if (componentName.equalsIgnoreCase("filtermanager")) {
158	tdb	1.39	component = new uk.org.iscream.cms.server.filtermanager.FilterManager(filterManagerName);
159	ajm	1.4	} else if (componentName.equalsIgnoreCase("rootfilter")) {
160	tdb	1.38	component = new uk.org.iscream.cms.server.rootfilter.RootFilter();
161	ajm	1.5	} else if (componentName.equalsIgnoreCase("dbinterface")) {
162	tdb	1.38	component = new uk.org.iscream.cms.server.dbinterface.DBInterface();
163	ajm	1.6	} else if (componentName.equalsIgnoreCase("clientinterface")) {
164	tdb	1.38	component = new uk.org.iscream.cms.server.clientinterface.ClientInterfaceMain();
165	ajm	1.7	// note the passing of the Filter's name in its constructor
166			} else if (componentName.equalsIgnoreCase("filter")) {
167	tdb	1.38	component = new uk.org.iscream.cms.server.filter.FilterMain(filterName);
168	tdb	1.30	} else if (componentName.equalsIgnoreCase("client")) {
169	tdb	1.38	component = new uk.org.iscream.cms.server.client.ClientMain();
170	ajm	1.1	}
171	ajm	1.2	// ### Add new component constructors in the above section! ###
172	ajm	1.3
173	ajm	1.22	// build the list of components to start
174	ajm	1.1	if (component != null) {
175	ajm	1.32	_componentsToStart.add(component);
176	ajm	1.13	} else {
177	tdb	1.33	System.err.println(toString + ": WARNING unsupported component not started: "+componentName);
178	ajm	1.13	}
179			}
180
181	ajm	1.32
182	ajm	1.22
183			// get the value for timeout
184	ajm	1.32
185	ajm	1.28	String confTimeout = null;
186	ajm	1.22	try {
187	tdb	1.38	confTimeout = System.getProperty("uk.org.iscream.cms.server.ComponentTimeout");
188	ajm	1.29	confTimeout.trim();
189	ajm	1.32	_startTimeout = Integer.parseInt(confTimeout);
190	ajm	1.22	} catch (NumberFormatException e) {
191	ajm	1.32	_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
192	tdb	1.38	System.err.println(toString + ": unable to read uk.org.iscream.cms.server.ComponentTimeout value (" + confTimeout + "), using default!");
193	ajm	1.22	}
194	ajm	1.32	System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
195	ajm	1.22
196	ajm	1.31	// startup the system components
197			startUp();
198
199			// block on the ORB...in time, management functionality can be placed here.
200			// if we detect a CORBA communication error, we'll restart all the components.
201	tdb	1.33	// !! this doesn't appear to work !!
202	ajm	1.31	while(true) {
203			try {
204			refman.getORB().run();
205	ajm	1.32	} catch (org.omg.CORBA.COMM_FAILURE e) {
206	ajm	1.31	System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
207			System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
208			}
209			startUp();
210			}
211			}
212
213			/**
214			* Starts the components as obtained from the configuration.
215			* This method calls the start() methods on all the components.
216			* If a component fails to start due to a CORBA communication
217			* problem, then it catches this and tries to start it again
218	tdb	1.38	* according to uk.org.iscream.cms.server.ComponentTimeout time.
219	ajm	1.31	*
220			* If the server dies and CORBA connections are lost, this method
221			* is called again.
222			*/
223			private static void startUp() {
224	ajm	1.32	// now we try and start the beast up
225			boolean tryAgain = true;
226			Component component = null;
227
228	ajm	1.22	// keep trying until we've started all the components.
229			// maybe add support for a limited number of retries
230	ajm	1.13	while(tryAgain) {
231	ajm	1.32	Iterator i = _componentsToStart.iterator();
232	tdb	1.33	LinkedList failedComponents = new LinkedList();
233	ajm	1.22	// go through all the components
234	ajm	1.13	while(i.hasNext()) {
235	tdb	1.33	// get a refence to the component
236			component = (Component) i.next();
237	tdb	1.35	System.out.println(toString + ": dependency checking component - " + component.toString());
238	tdb	1.33
239			// check it's dependencies
240			boolean depOK = component.depCheck();
241			if(depOK) {
242	tdb	1.35	System.out.println(toString + ": starting component - " + component.toString());
243	tdb	1.33	// it should be ok to start the component
244			try {
245			// start the component
246			component.start();
247			} catch (ComponentStartException e) {
248			// if we get this then there was a problem
249			// that we can't recover from
250			System.err.println(toString + ": ERROR starting component - " + component.toString());
251			System.err.println(toString + ": component reports - " + e.getMessage());
252			System.exit(1);
253			}
254			}
255			else {
256			// it seems the depedencies failed
257			// so we want to try again after a delay
258			System.err.println(toString + ": WARNING Component reported dependency failure");
259	ajm	1.14	System.err.println(toString + ": This could be because it can't communicate with components it needs.");
260	ajm	1.22
261			// make a list of the failed components
262	ajm	1.20	failedComponents.add(component);
263	ajm	1.1	}
264	ajm	1.13	}
265	ajm	1.22
266			// if we had some failed components that we can retry
267	ajm	1.21	if (failedComponents.size() > 0) {
268	ajm	1.14	System.err.println(toString + ": WARNING One or more components failed to start correctly.");
269	ajm	1.32	System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
270	ajm	1.22
271			// our list is now the failed list
272	ajm	1.32	_componentsToStart = failedComponents;
273	ajm	1.22
274			// sleep for a given timeout
275	ajm	1.18	try {
276	ajm	1.32	Thread.sleep(_startTimeout * 1000);
277	ajm	1.17	} catch (InterruptedException e) {
278			// we're not bothered
279			}
280	ajm	1.22	// otherwise we started everything
281	ajm	1.18	} else {
282	ajm	1.22	// so we set to exit the loop
283	ajm	1.18	tryAgain = false;
284	ajm	1.1	}
285			}
286	ajm	1.13
287	ajm	1.3	System.out.println(toString + ": running");
288	ajm	1.31	}
289	ajm	1.3
290			/**
291	ajm	1.1	* A simple method to print the usage of this class.
292			* It never returns, but instead exits to the system
293			* with a value 1, to indicate the system did not start
294			* properly.
295			*/
296			public static void usage() {
297	tdb	1.38	System.out.println("USAGE: java uk.org.iscream.cms.server.componentmanager.ComponentManager <option>");
298	tdb	1.8	System.out.println(" or: java -jar iscream.jar <option>");
299	ajm	1.1	System.out.println("WHERE <option>:");
300			System.out.println(" -l <filename> - the location of initial system properties");
301	ajm	1.2	System.out.println(" the default is ./etc/default.properties");
302	ajm	1.1	System.out.println(" -f <name> - the name of the filter (if there is one configured");
303	tdb	1.39	System.out.println(" -fm <name> - the name of the filter manager (if there is one configured");
304	ajm	1.1	System.out.println(" -h - this help screen");
305			System.exit(1);
306			}
307
308			//---CONSTRUCTORS---
309
310			//---PUBLIC METHODS---
311
312			//---PRIVATE METHODS---
313
314			//---ACCESSOR/MUTATOR METHODS---
315
316			//---ATTRIBUTES---
317
318			//---STATIC ATTRIBUTES---
319	ajm	1.32
320	tdb	1.33	private static LinkedList _componentsToStart;
321	ajm	1.32	private static int _startTimeout = 0;
322	ajm	1.1
323			}