Ssh.java

/**
 *  Copyright 2007-2008 University Of Southern California
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package edu.isi.pegasus.common.credential.impl;

import java.io.File;
import java.util.Map;

import edu.isi.pegasus.common.credential.CredentialHandler;
import edu.isi.pegasus.planner.catalog.classes.Profiles;
import edu.isi.pegasus.planner.catalog.site.classes.SiteCatalogEntry;
import edu.isi.pegasus.planner.classes.PegasusBag;
import edu.isi.pegasus.planner.namespace.Namespace;




/**
 * A convenience class that allows us to determine the path to the user ssh private key file.
 *
 * @author Mats Rynge
 * @author Karan Vahi
 *
 * @version $Revision: 4817 $
 */
public class Ssh extends Abstract implements CredentialHandler {

    /**
     * The name of the environment variable that specifies the path to the
     * SSH key.
     */
    public static final String SSH_PRIVATE_KEY_VARIABLE = "SSH_PRIVATE_KEY";
    
    
    private static final String SSH_PRIVATE_KEY_PEGASUS_PROFILE_KEY = SSH_PRIVATE_KEY_VARIABLE.toLowerCase() ;//has to be lowercased

    /**
     * The description
     */
    private static final String DESCRIPTION = "SSH private key Credential Handler";


    /**
     * The local path to the credential
     */
    private String mLocalCredentialPath;
    
    /**
     * The default constructor.
     */
    public Ssh(){
        super();
    }
    
    /**
     * Initializes the credential implementation. Implementations require
     * access to the logger, properties and the SiteCatalog Store.
     *
     * @param bag  the bag of Pegasus objects.
     */
    public void initialize( PegasusBag bag ){
        super.initialize( bag );
        mLocalCredentialPath = this.getLocalPath();
    }

    
    /**
     * Returns the path to SSH_PRIVATE_KEY . The order of preference is as follows
     *
     * - If a SSH_PRIVATE_KEY is specified as a Pegasus Profile in the site catalog
     * - Else the path on the local site
     *
     * @param site   the  site handle
     *
     * @return  the path to SSH private key for the site.
     */
    public  String getPath( String site ){

        SiteCatalogEntry siteEntry = mSiteStore.lookup( site );
        //check if one is specified in site catalog entry
        String path = ( siteEntry == null )? null :
                       (String)siteEntry.getProfiles().get( Profiles.NAMESPACES.pegasus).get( Ssh.SSH_PRIVATE_KEY_VARIABLE.toLowerCase().toLowerCase() );

        return( path == null ) ?
                //PM-731 return the path on the local site
                this.mLocalCredentialPath:
                path;
       
    }

    /**
     * Returns the path to user cred on the local site. 
     * The order of preference is as follows
     *
     * - If a SSH_PRIVATE_KEY is specified in the site catalog entry as a Pegasus Profile that is used, else the corresponding env profile for backward support
     * - Else the Pegasus Profile SSH_PRIVATE_KEY specified in the properties, else the corresponding env profile for backward support
     * - Else the one pointed to by the environment variable SSH_PRIVATE_KEY
     * 
     * 
     * @param site   the  site catalog entry object.
     *
     * @return  the path to user cred.
     */
    public String getLocalPath(){
        SiteCatalogEntry siteEntry = mSiteStore.lookup( "local" );
        
        //check if corresponding Pegasus Profile is specified in site catalog entry
        String cred = ( siteEntry == null )? null :
                        (String)siteEntry.getProfiles().get( Profiles.NAMESPACES.pegasus).get( Ssh.SSH_PRIVATE_KEY_PEGASUS_PROFILE_KEY  );
        if( cred == null && siteEntry != null ){
            //try to check for an env profile in the site entry 
            cred = (String)siteEntry.getProfiles().get( Profiles.NAMESPACES.env).get( Ssh.SSH_PRIVATE_KEY_VARIABLE );
        }
        
        //try from properites file
        if( cred == null ){
            //load the pegasus profile from property file 
            Namespace profiles = mProps.getProfiles(Profiles.NAMESPACES.pegasus);
            cred = (String)profiles.get( Ssh.SSH_PRIVATE_KEY_PEGASUS_PROFILE_KEY  );
        }
        if( cred == null ) {
            //load the backup env profile from property file 
            Namespace env = mProps.getProfiles(Profiles.NAMESPACES.env);
            cred = (String)env.get( Ssh.SSH_PRIVATE_KEY_VARIABLE  );
        }
        
        //try from environment
        if( cred == null){
            //check if X509_USER_PROXY is specified in the environment
            Map<String,String> envs = System.getenv();
            if( envs.containsKey( Ssh.SSH_PRIVATE_KEY_VARIABLE ) ){
                cred = envs.get( Ssh.SSH_PRIVATE_KEY_VARIABLE  );
            }
        }

        return cred;
    }
    
    /**
     * returns the basename of the path to the local credential
     * 
     * @param site  the site handle
     */
    public String getBaseName( String site ) {
        File path = new File(this.getPath( site ));
        return path.getName();
    }

    /**
     * Returns the env or pegasus profile key that needs to be associated
     * for the credential.
     * 
     * @return the name of the environment variable.
     */
    public String getProfileKey( ){
        return Ssh.SSH_PRIVATE_KEY_VARIABLE;
    }

    /**
     * Returns the name of the environment variable that needs to be set
     * for the job associated with the credential.
     *
     * @return the name of the environment variable.
     */
    public String getEnvironmentVariable( String site ){
        return Ssh.SSH_PRIVATE_KEY_VARIABLE + "_" + this.getSiteNameForEnvironmentKey(site) ;
    }

    /**
     * Returns the description for the implementing handler
     *
     * @return  description
     */
    public String getDescription(){
        return Ssh.DESCRIPTION;
    }
}