server/componentmanager/ComponentManager.java

/* 
 * i-scream central monitoring system
 * 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.server.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 1.39 2002/03/20 13:40:29 tdb Exp $
 */
public class ComponentManager {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.39 $";
    
    /**
     * 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:	1.40
Committed:	Sat May 18 18:16:01 2002 UTC (22 years ago) by tdb
Branch:	MAIN
Changes since 1.39:	+21 -2 lines
Log Message:	i-scream is now licensed under the GPL. I've added the GPL headers to every source file, and put a full copy of the license in the appropriate places. I think I've covered everything. This is going to be a mad commit ;)
#	User	Rev	Content
1	tdb	1.40	/*
2			* i-scream central monitoring system
3			* Copyright (C) 2000-2002 i-scream
4			*
5			* This program is free software; you can redistribute it and/or
6			* modify it under the terms of the GNU General Public License
7			* as published by the Free Software Foundation; either version 2
8			* of the License, or (at your option) any later version.
9			*
10			* This program is distributed in the hope that it will be useful,
11			* but WITHOUT ANY WARRANTY; without even the implied warranty of
12			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13			* GNU General Public License for more details.
14			*
15			* You should have received a copy of the GNU General Public License
16			* along with this program; if not, write to the Free Software
17			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18			*/
19
20	ajm	1.1	//---PACKAGE DECLARATION---
21	tdb	1.38	package uk.org.iscream.cms.server.componentmanager;
22	ajm	1.1
23			//---IMPORTS---
24			import java.util.*;
25			import java.io.*;
26	tdb	1.38	import uk.org.iscream.cms.server.util.*;
27	ajm	1.1
28			/**
29	ajm	1.2	* The component manager is the starting point for all
30			* server side components of the iscream system.
31			* It loads its initial system configuration from the
32			* default properties file, it then starts all the iscream
33			* components as specified in the default.properties under
34	tdb	1.38	* uk.org.iscream.cms.server.ComponentList
35	ajm	1.1	*
36	tdb	1.39	* @author $Author: tdb $
37	tdb	1.40	* @version $Id: ComponentManager.java,v 1.39 2002/03/20 13:40:29 tdb Exp $
38	ajm	1.1	*/
39			public class ComponentManager {
40
41			//---FINAL ATTRIBUTES---
42
43			/**
44			* The current CVS revision of this class
45			*/
46	tdb	1.40	public static final String REVISION = "$Revision: 1.39 $";
47	ajm	1.1
48			/**
49			* The toString() of this class
50			* As it won't be instatiated, this is needed.
51	ajm	1.2	* Not also that we pass a null as the class name (as we are static)
52	ajm	1.1	*/
53	ajm	1.2	public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
54	ajm	1.1
55			/**
56			* The default location of the properties file for the system
57			*/
58	ajm	1.2	public static final String DEFAULTPROPERTIES = "./etc/default.properties";
59	ajm	1.1
60	ajm	1.22	/**
61			* The default time to wait before retrying
62			* component.
63			*/
64			public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
65
66	ajm	1.1	//---STATIC METHODS---
67
68			/**
69	ajm	1.2	* The main method which starts the components as
70			* listed in the default.properties file.
71	ajm	1.1	*
72			* @param args the command line arguments
73			*/
74			public static void main(String[] args) {
75	ajm	1.36	System.out.println("-----------------------------------------");
76	tdb	1.11	System.out.println("--- i-scream Server Component Manager ---");
77	tdb	1.37	System.out.println("--- (c) 2001 The i-scream Project ---");
78	ajm	1.36	System.out.println("--- (http://www.i-scream.org.uk) ---");
79			System.out.println("-----------------------------------------");
80	ajm	1.2	System.out.println("--- Starting System ---");
81
82	ajm	1.1	// get the command line args
83			String defaultProperties = DEFAULTPROPERTIES;
84			String filterName = null;
85	tdb	1.39	String filterManagerName = null;
86	tdb	1.11	for(int i=0; i < args.length; i++) {
87	tdb	1.12	if(args[i].equals("-h")) {
88	ajm	1.1	usage();
89	tdb	1.11	}
90	tdb	1.12	else if(args[i].equals("-f")) {
91	tdb	1.39	if(++i < args.length) {
92			filterName = args[i];
93			}
94			else {
95			usage();
96			}
97			}
98			else if(args[i].equals("-fm")) {
99			if(++i < args.length) {
100			filterManagerName = args[i];
101			}
102			else {
103			usage();
104			}
105	tdb	1.11	}
106	tdb	1.12	else if(args[i].equals("-l")) {
107	tdb	1.39	if(++i < args.length) {
108			defaultProperties = args[i];
109			}
110			else {
111			usage();
112			}
113	tdb	1.11	}
114			else {
115			usage();
116			}
117	ajm	1.1	}
118
119			// load the default properties file into the system properties
120			System.out.println(toString + ": initialising - using " + defaultProperties);
121			try {
122			Properties initProperties = new Properties(System.getProperties());
123			initProperties.load(new FileInputStream(new File(defaultProperties)));
124			System.setProperties(initProperties);
125			} catch (Exception e) {
126			System.err.println(toString + ": ERROR " + e.getMessage());
127			usage();
128			}
129
130			// continue to bring the system up
131			System.out.println(toString + ": coming up");
132
133			// start the ORB by initialising the ReferenceManager
134	ajm	1.2	ReferenceManager refman = ReferenceManager.getInstance();
135	ajm	1.1
136	ajm	1.2	// now the ORB is running, we need to activate our RootPOA
137			// so that we can start serving requests once servants start up
138	ajm	1.1	refman.activatePOA();
139
140	ajm	1.2	// get the list of components
141	tdb	1.38	String componentList = System.getProperty("uk.org.iscream.cms.server.ComponentList");
142	ajm	1.1	StringTokenizer st = new StringTokenizer(componentList, ";");
143	tdb	1.33	_componentsToStart = new LinkedList();
144	ajm	1.13
145	ajm	1.1	// this could be done using reflection
146			// but..well..we don't ;-p
147			while (st.hasMoreTokens()){
148			String componentName = st.nextToken();
149			Component component = null;
150	ajm	1.13
151	ajm	1.2
152			// ### This is where the list of supported components is checked! ###
153			if (componentName.equalsIgnoreCase("core")) {
154	tdb	1.38	component = new uk.org.iscream.cms.server.core.Core();
155	tdb	1.39	// note the passing of the FilterManagers's name in its constructor
156	ajm	1.3	} else if (componentName.equalsIgnoreCase("filtermanager")) {
157	tdb	1.39	component = new uk.org.iscream.cms.server.filtermanager.FilterManager(filterManagerName);
158	ajm	1.4	} else if (componentName.equalsIgnoreCase("rootfilter")) {
159	tdb	1.38	component = new uk.org.iscream.cms.server.rootfilter.RootFilter();
160	ajm	1.5	} else if (componentName.equalsIgnoreCase("dbinterface")) {
161	tdb	1.38	component = new uk.org.iscream.cms.server.dbinterface.DBInterface();
162	ajm	1.6	} else if (componentName.equalsIgnoreCase("clientinterface")) {
163	tdb	1.38	component = new uk.org.iscream.cms.server.clientinterface.ClientInterfaceMain();
164	ajm	1.7	// note the passing of the Filter's name in its constructor
165			} else if (componentName.equalsIgnoreCase("filter")) {
166	tdb	1.38	component = new uk.org.iscream.cms.server.filter.FilterMain(filterName);
167	tdb	1.30	} else if (componentName.equalsIgnoreCase("client")) {
168	tdb	1.38	component = new uk.org.iscream.cms.server.client.ClientMain();
169	ajm	1.1	}
170	ajm	1.2	// ### Add new component constructors in the above section! ###
171	ajm	1.3
172	ajm	1.22	// build the list of components to start
173	ajm	1.1	if (component != null) {
174	ajm	1.32	_componentsToStart.add(component);
175	ajm	1.13	} else {
176	tdb	1.33	System.err.println(toString + ": WARNING unsupported component not started: "+componentName);
177	ajm	1.13	}
178			}
179
180	ajm	1.32
181	ajm	1.22
182			// get the value for timeout
183	ajm	1.32
184	ajm	1.28	String confTimeout = null;
185	ajm	1.22	try {
186	tdb	1.38	confTimeout = System.getProperty("uk.org.iscream.cms.server.ComponentTimeout");
187	ajm	1.29	confTimeout.trim();
188	ajm	1.32	_startTimeout = Integer.parseInt(confTimeout);
189	ajm	1.22	} catch (NumberFormatException e) {
190	ajm	1.32	_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
191	tdb	1.38	System.err.println(toString + ": unable to read uk.org.iscream.cms.server.ComponentTimeout value (" + confTimeout + "), using default!");
192	ajm	1.22	}
193	ajm	1.32	System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
194	ajm	1.22
195	ajm	1.31	// startup the system components
196			startUp();
197
198			// block on the ORB...in time, management functionality can be placed here.
199			// if we detect a CORBA communication error, we'll restart all the components.
200	tdb	1.33	// !! this doesn't appear to work !!
201	ajm	1.31	while(true) {
202			try {
203			refman.getORB().run();
204	ajm	1.32	} catch (org.omg.CORBA.COMM_FAILURE e) {
205	ajm	1.31	System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
206			System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
207			}
208			startUp();
209			}
210			}
211
212			/**
213			* Starts the components as obtained from the configuration.
214			* This method calls the start() methods on all the components.
215			* If a component fails to start due to a CORBA communication
216			* problem, then it catches this and tries to start it again
217	tdb	1.38	* according to uk.org.iscream.cms.server.ComponentTimeout time.
218	ajm	1.31	*
219			* If the server dies and CORBA connections are lost, this method
220			* is called again.
221			*/
222			private static void startUp() {
223	ajm	1.32	// now we try and start the beast up
224			boolean tryAgain = true;
225			Component component = null;
226
227	ajm	1.22	// keep trying until we've started all the components.
228			// maybe add support for a limited number of retries
229	ajm	1.13	while(tryAgain) {
230	ajm	1.32	Iterator i = _componentsToStart.iterator();
231	tdb	1.33	LinkedList failedComponents = new LinkedList();
232	ajm	1.22	// go through all the components
233	ajm	1.13	while(i.hasNext()) {
234	tdb	1.33	// get a refence to the component
235			component = (Component) i.next();
236	tdb	1.35	System.out.println(toString + ": dependency checking component - " + component.toString());
237	tdb	1.33
238			// check it's dependencies
239			boolean depOK = component.depCheck();
240			if(depOK) {
241	tdb	1.35	System.out.println(toString + ": starting component - " + component.toString());
242	tdb	1.33	// it should be ok to start the component
243			try {
244			// start the component
245			component.start();
246			} catch (ComponentStartException e) {
247			// if we get this then there was a problem
248			// that we can't recover from
249			System.err.println(toString + ": ERROR starting component - " + component.toString());
250			System.err.println(toString + ": component reports - " + e.getMessage());
251			System.exit(1);
252			}
253			}
254			else {
255			// it seems the depedencies failed
256			// so we want to try again after a delay
257			System.err.println(toString + ": WARNING Component reported dependency failure");
258	ajm	1.14	System.err.println(toString + ": This could be because it can't communicate with components it needs.");
259	ajm	1.22
260			// make a list of the failed components
261	ajm	1.20	failedComponents.add(component);
262	ajm	1.1	}
263	ajm	1.13	}
264	ajm	1.22
265			// if we had some failed components that we can retry
266	ajm	1.21	if (failedComponents.size() > 0) {
267	ajm	1.14	System.err.println(toString + ": WARNING One or more components failed to start correctly.");
268	ajm	1.32	System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
269	ajm	1.22
270			// our list is now the failed list
271	ajm	1.32	_componentsToStart = failedComponents;
272	ajm	1.22
273			// sleep for a given timeout
274	ajm	1.18	try {
275	ajm	1.32	Thread.sleep(_startTimeout * 1000);
276	ajm	1.17	} catch (InterruptedException e) {
277			// we're not bothered
278			}
279	ajm	1.22	// otherwise we started everything
280	ajm	1.18	} else {
281	ajm	1.22	// so we set to exit the loop
282	ajm	1.18	tryAgain = false;
283	ajm	1.1	}
284			}
285	ajm	1.13
286	ajm	1.3	System.out.println(toString + ": running");
287	ajm	1.31	}
288	ajm	1.3
289			/**
290	ajm	1.1	* A simple method to print the usage of this class.
291			* It never returns, but instead exits to the system
292			* with a value 1, to indicate the system did not start
293			* properly.
294			*/
295			public static void usage() {
296	tdb	1.38	System.out.println("USAGE: java uk.org.iscream.cms.server.componentmanager.ComponentManager <option>");
297	tdb	1.8	System.out.println(" or: java -jar iscream.jar <option>");
298	ajm	1.1	System.out.println("WHERE <option>:");
299			System.out.println(" -l <filename> - the location of initial system properties");
300	ajm	1.2	System.out.println(" the default is ./etc/default.properties");
301	ajm	1.1	System.out.println(" -f <name> - the name of the filter (if there is one configured");
302	tdb	1.39	System.out.println(" -fm <name> - the name of the filter manager (if there is one configured");
303	ajm	1.1	System.out.println(" -h - this help screen");
304			System.exit(1);
305			}
306
307			//---CONSTRUCTORS---
308
309			//---PUBLIC METHODS---
310
311			//---PRIVATE METHODS---
312
313			//---ACCESSOR/MUTATOR METHODS---
314
315			//---ATTRIBUTES---
316
317			//---STATIC ATTRIBUTES---
318	ajm	1.32
319	tdb	1.33	private static LinkedList _componentsToStart;
320	ajm	1.32	private static int _startTimeout = 0;
321	ajm	1.1
322			}