server/componentmanager/ComponentManager.java

//---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: tdb1 $
 * @version $Id: ComponentManager.java,v 1.37 2001/03/19 19:14:25 tdb1 Exp $
 */
public class ComponentManager {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.37 $";
    
    /**
     * 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;
        for(int i=0; i < args.length; i++) {
            if(args[i].equals("-h")) {
                usage();
            }
            else if(args[i].equals("-f")) {
                i++; filterName = args[i];
            }
            else if(args[i].equals("-l")) {
                i++; defaultProperties = args[i];
            }
            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();
            } else if (componentName.equalsIgnoreCase("filtermanager")) {
                component = new uk.org.iscream.cms.server.filtermanager.FilterManager();
            } 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("      -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:	1.38
Committed:	Tue May 29 17:02:34 2001 UTC (24 years, 6 months ago) by tdb
Branch:	MAIN
Branch point for:	SERVER_PIRCBOT
Changes since 1.37:	+18 -18 lines
Log Message:	Major change in the java package naming. This has been held off for some time now, but it really needed doing. The future packaging of all i-scream products will be; uk.org.iscream.<product>.<subpart>.* In the case of the central monitoring system server this will be; uk.org.iscream.cms.server.* The whole server has been changed to follow this structure, and tested to a smallish extent. Further changes in other parts of the CMS will follow.
#	User	Rev	Content
1	ajm	1.1	//---PACKAGE DECLARATION---
2	tdb	1.38	package uk.org.iscream.cms.server.componentmanager;
3	ajm	1.1
4			//---IMPORTS---
5			import java.util.*;
6			import java.io.*;
7	tdb	1.38	import uk.org.iscream.cms.server.util.*;
8	ajm	1.1
9			/**
10	ajm	1.2	* The component manager is the starting point for all
11			* server side components of the iscream system.
12			* It loads its initial system configuration from the
13			* default properties file, it then starts all the iscream
14			* components as specified in the default.properties under
15	tdb	1.38	* uk.org.iscream.cms.server.ComponentList
16	ajm	1.1	*
17	tdb	1.38	* @author $Author: tdb1 $
18			* @version $Id: ComponentManager.java,v 1.37 2001/03/19 19:14:25 tdb1 Exp $
19	ajm	1.1	*/
20			public class ComponentManager {
21
22			//---FINAL ATTRIBUTES---
23
24			/**
25			* The current CVS revision of this class
26			*/
27	tdb	1.38	public static final String REVISION = "$Revision: 1.37 $";
28	ajm	1.1
29			/**
30			* The toString() of this class
31			* As it won't be instatiated, this is needed.
32	ajm	1.2	* Not also that we pass a null as the class name (as we are static)
33	ajm	1.1	*/
34	ajm	1.2	public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
35	ajm	1.1
36			/**
37			* The default location of the properties file for the system
38			*/
39	ajm	1.2	public static final String DEFAULTPROPERTIES = "./etc/default.properties";
40	ajm	1.1
41	ajm	1.22	/**
42			* The default time to wait before retrying
43			* component.
44			*/
45			public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
46
47	ajm	1.1	//---STATIC METHODS---
48
49			/**
50	ajm	1.2	* The main method which starts the components as
51			* listed in the default.properties file.
52	ajm	1.1	*
53			* @param args the command line arguments
54			*/
55			public static void main(String[] args) {
56	ajm	1.36	System.out.println("-----------------------------------------");
57	tdb	1.11	System.out.println("--- i-scream Server Component Manager ---");
58	tdb	1.37	System.out.println("--- (c) 2001 The i-scream Project ---");
59	ajm	1.36	System.out.println("--- (http://www.i-scream.org.uk) ---");
60			System.out.println("-----------------------------------------");
61	ajm	1.2	System.out.println("--- Starting System ---");
62
63	ajm	1.1	// get the command line args
64			String defaultProperties = DEFAULTPROPERTIES;
65			String filterName = null;
66	tdb	1.11	for(int i=0; i < args.length; i++) {
67	tdb	1.12	if(args[i].equals("-h")) {
68	ajm	1.1	usage();
69	tdb	1.11	}
70	tdb	1.12	else if(args[i].equals("-f")) {
71	tdb	1.11	i++; filterName = args[i];
72			}
73	tdb	1.12	else if(args[i].equals("-l")) {
74	tdb	1.11	i++; defaultProperties = args[i];
75			}
76			else {
77			usage();
78			}
79	ajm	1.1	}
80
81			// load the default properties file into the system properties
82			System.out.println(toString + ": initialising - using " + defaultProperties);
83			try {
84			Properties initProperties = new Properties(System.getProperties());
85			initProperties.load(new FileInputStream(new File(defaultProperties)));
86			System.setProperties(initProperties);
87			} catch (Exception e) {
88			System.err.println(toString + ": ERROR " + e.getMessage());
89			usage();
90			}
91
92			// continue to bring the system up
93			System.out.println(toString + ": coming up");
94
95			// start the ORB by initialising the ReferenceManager
96	ajm	1.2	ReferenceManager refman = ReferenceManager.getInstance();
97	ajm	1.1
98	ajm	1.2	// now the ORB is running, we need to activate our RootPOA
99			// so that we can start serving requests once servants start up
100	ajm	1.1	refman.activatePOA();
101
102	ajm	1.2	// get the list of components
103	tdb	1.38	String componentList = System.getProperty("uk.org.iscream.cms.server.ComponentList");
104	ajm	1.1	StringTokenizer st = new StringTokenizer(componentList, ";");
105	tdb	1.33	_componentsToStart = new LinkedList();
106	ajm	1.13
107	ajm	1.1	// this could be done using reflection
108			// but..well..we don't ;-p
109			while (st.hasMoreTokens()){
110			String componentName = st.nextToken();
111			Component component = null;
112	ajm	1.13
113	ajm	1.2
114			// ### This is where the list of supported components is checked! ###
115			if (componentName.equalsIgnoreCase("core")) {
116	tdb	1.38	component = new uk.org.iscream.cms.server.core.Core();
117	ajm	1.3	} else if (componentName.equalsIgnoreCase("filtermanager")) {
118	tdb	1.38	component = new uk.org.iscream.cms.server.filtermanager.FilterManager();
119	ajm	1.4	} else if (componentName.equalsIgnoreCase("rootfilter")) {
120	tdb	1.38	component = new uk.org.iscream.cms.server.rootfilter.RootFilter();
121	ajm	1.5	} else if (componentName.equalsIgnoreCase("dbinterface")) {
122	tdb	1.38	component = new uk.org.iscream.cms.server.dbinterface.DBInterface();
123	ajm	1.6	} else if (componentName.equalsIgnoreCase("clientinterface")) {
124	tdb	1.38	component = new uk.org.iscream.cms.server.clientinterface.ClientInterfaceMain();
125	ajm	1.7	// note the passing of the Filter's name in its constructor
126			} else if (componentName.equalsIgnoreCase("filter")) {
127	tdb	1.38	component = new uk.org.iscream.cms.server.filter.FilterMain(filterName);
128	tdb	1.30	} else if (componentName.equalsIgnoreCase("client")) {
129	tdb	1.38	component = new uk.org.iscream.cms.server.client.ClientMain();
130	ajm	1.1	}
131	ajm	1.2	// ### Add new component constructors in the above section! ###
132	ajm	1.3
133	ajm	1.22	// build the list of components to start
134	ajm	1.1	if (component != null) {
135	ajm	1.32	_componentsToStart.add(component);
136	ajm	1.13	} else {
137	tdb	1.33	System.err.println(toString + ": WARNING unsupported component not started: "+componentName);
138	ajm	1.13	}
139			}
140
141	ajm	1.32
142	ajm	1.22
143			// get the value for timeout
144	ajm	1.32
145	ajm	1.28	String confTimeout = null;
146	ajm	1.22	try {
147	tdb	1.38	confTimeout = System.getProperty("uk.org.iscream.cms.server.ComponentTimeout");
148	ajm	1.29	confTimeout.trim();
149	ajm	1.32	_startTimeout = Integer.parseInt(confTimeout);
150	ajm	1.22	} catch (NumberFormatException e) {
151	ajm	1.32	_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
152	tdb	1.38	System.err.println(toString + ": unable to read uk.org.iscream.cms.server.ComponentTimeout value (" + confTimeout + "), using default!");
153	ajm	1.22	}
154	ajm	1.32	System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
155	ajm	1.22
156	ajm	1.31	// startup the system components
157			startUp();
158
159			// block on the ORB...in time, management functionality can be placed here.
160			// if we detect a CORBA communication error, we'll restart all the components.
161	tdb	1.33	// !! this doesn't appear to work !!
162	ajm	1.31	while(true) {
163			try {
164			refman.getORB().run();
165	ajm	1.32	} catch (org.omg.CORBA.COMM_FAILURE e) {
166	ajm	1.31	System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
167			System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
168			}
169			startUp();
170			}
171			}
172
173			/**
174			* Starts the components as obtained from the configuration.
175			* This method calls the start() methods on all the components.
176			* If a component fails to start due to a CORBA communication
177			* problem, then it catches this and tries to start it again
178	tdb	1.38	* according to uk.org.iscream.cms.server.ComponentTimeout time.
179	ajm	1.31	*
180			* If the server dies and CORBA connections are lost, this method
181			* is called again.
182			*/
183			private static void startUp() {
184	ajm	1.32	// now we try and start the beast up
185			boolean tryAgain = true;
186			Component component = null;
187
188	ajm	1.22	// keep trying until we've started all the components.
189			// maybe add support for a limited number of retries
190	ajm	1.13	while(tryAgain) {
191	ajm	1.32	Iterator i = _componentsToStart.iterator();
192	tdb	1.33	LinkedList failedComponents = new LinkedList();
193	ajm	1.22	// go through all the components
194	ajm	1.13	while(i.hasNext()) {
195	tdb	1.33	// get a refence to the component
196			component = (Component) i.next();
197	tdb	1.35	System.out.println(toString + ": dependency checking component - " + component.toString());
198	tdb	1.33
199			// check it's dependencies
200			boolean depOK = component.depCheck();
201			if(depOK) {
202	tdb	1.35	System.out.println(toString + ": starting component - " + component.toString());
203	tdb	1.33	// it should be ok to start the component
204			try {
205			// start the component
206			component.start();
207			} catch (ComponentStartException e) {
208			// if we get this then there was a problem
209			// that we can't recover from
210			System.err.println(toString + ": ERROR starting component - " + component.toString());
211			System.err.println(toString + ": component reports - " + e.getMessage());
212			System.exit(1);
213			}
214			}
215			else {
216			// it seems the depedencies failed
217			// so we want to try again after a delay
218			System.err.println(toString + ": WARNING Component reported dependency failure");
219	ajm	1.14	System.err.println(toString + ": This could be because it can't communicate with components it needs.");
220	ajm	1.22
221			// make a list of the failed components
222	ajm	1.20	failedComponents.add(component);
223	ajm	1.1	}
224	ajm	1.13	}
225	ajm	1.22
226			// if we had some failed components that we can retry
227	ajm	1.21	if (failedComponents.size() > 0) {
228	ajm	1.14	System.err.println(toString + ": WARNING One or more components failed to start correctly.");
229	ajm	1.32	System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
230	ajm	1.22
231			// our list is now the failed list
232	ajm	1.32	_componentsToStart = failedComponents;
233	ajm	1.22
234			// sleep for a given timeout
235	ajm	1.18	try {
236	ajm	1.32	Thread.sleep(_startTimeout * 1000);
237	ajm	1.17	} catch (InterruptedException e) {
238			// we're not bothered
239			}
240	ajm	1.22	// otherwise we started everything
241	ajm	1.18	} else {
242	ajm	1.22	// so we set to exit the loop
243	ajm	1.18	tryAgain = false;
244	ajm	1.1	}
245			}
246	ajm	1.13
247	ajm	1.3	System.out.println(toString + ": running");
248	ajm	1.31	}
249	ajm	1.3
250			/**
251	ajm	1.1	* A simple method to print the usage of this class.
252			* It never returns, but instead exits to the system
253			* with a value 1, to indicate the system did not start
254			* properly.
255			*/
256			public static void usage() {
257	tdb	1.38	System.out.println("USAGE: java uk.org.iscream.cms.server.componentmanager.ComponentManager <option>");
258	tdb	1.8	System.out.println(" or: java -jar iscream.jar <option>");
259	ajm	1.1	System.out.println("WHERE <option>:");
260			System.out.println(" -l <filename> - the location of initial system properties");
261	ajm	1.2	System.out.println(" the default is ./etc/default.properties");
262	ajm	1.1	System.out.println(" -f <name> - the name of the filter (if there is one configured");
263			System.out.println(" -h - this help screen");
264			System.exit(1);
265			}
266
267			//---CONSTRUCTORS---
268
269			//---PUBLIC METHODS---
270
271			//---PRIVATE METHODS---
272
273			//---ACCESSOR/MUTATOR METHODS---
274
275			//---ATTRIBUTES---
276
277			//---STATIC ATTRIBUTES---
278	ajm	1.32
279	tdb	1.33	private static LinkedList _componentsToStart;
280	ajm	1.32	private static int _startTimeout = 0;
281	ajm	1.1
282			}