path: root/src/mongo/shell/utils.js

__quiet = false;
__magicNoPrint = { __magicNoPrint : 1111 }
__callLastError = false; 
_verboseShell = false;

chatty = function(s){
    if ( ! __quiet )
        print( s );
}

friendlyEqual = function( a , b ){
    if ( a == b )
        return true;
    
    a = tojson(a,false,true);
    b = tojson(b,false,true);

    if ( a == b )
        return true;

    var clean = function( s ){
        s = s.replace( /NumberInt\((\-?\d+)\)/g , "$1" );
        return s;
    }
    
    a = clean(a);
    b = clean(b);

    if ( a == b )
        return true;
    
    return false;
}

printStackTrace = function(){
    try{
        throw new Error("Printing Stack Trace");
    } catch (e) {
        print(e.stack);
    }
}

/**
 * <p> Set the shell verbosity. If verbose the shell will display more information about command results. </>
 * <p> Default is off. <p>
 * @param {Bool} verbosity on / off
 */
setVerboseShell = function( value ) { 
    if( value == undefined ) value = true; 
    _verboseShell = value; 
}

argumentsToArray = function( a ){
    var arr = [];
    for ( var i=0; i<a.length; i++ )
        arr[i] = a[i];
    return arr;
}

// Formats a simple stacked horizontal histogram bar in the shell.
// @param data array of the form [[ratio, symbol], ...] where ratio is between 0 and 1 and
//             symbol is a string of length 1
// @param width width of the bar (excluding the left and right delimiters [ ] )
// e.g. _barFormat([[.3, "="], [.5, '-']], 80) returns
//      "[========================----------------------------------------                ]"
_barFormat = function(data, width) {
    var remaining = width;
    var res = "[";
    for (var i = 0; i < data.length; i++) {
        for (var x = 0; x < data[i][0] * width; x++) {
            if (remaining-- > 0) {
                res += data[i][1];
            }
        }
    }
    while (remaining-- > 0) {
        res += " ";
    }
    res += "]";
    return res;
}


//these two are helpers for Array.sort(func)
compare = function(l, r){ return (l == r ? 0 : (l < r ? -1 : 1)); }

// arr.sort(compareOn('name'))
compareOn = function(field){
    return function(l, r) { return compare(l[field], r[field]); }
}

if ( typeof _threadInject != "undefined" ){
    //print( "fork() available!" );
    
    Thread = function(){
        this.init.apply( this, arguments );
    }
    _threadInject( Thread.prototype );
    
    ScopedThread = function() {
        this.init.apply( this, arguments );
    }
    ScopedThread.prototype = new Thread( function() {} );
    _scopedThreadInject( ScopedThread.prototype );
    
    fork = function() {
        var t = new Thread( function() {} );
        Thread.apply( t, arguments );
        return t;
    }    

    // Helper class to generate a list of events which may be executed by a ParallelTester
    EventGenerator = function( me, collectionName, mean, host ) {
        this.mean = mean;
        if (host == undefined) host = db.getMongo().host;
        this.events = new Array( me, collectionName, host );
    }
    
    EventGenerator.prototype._add = function( action ) {
        this.events.push( [ Random.genExp( this.mean ), action ] );
    }
    
    EventGenerator.prototype.addInsert = function( obj ) {
        this._add( "t.insert( " + tojson( obj ) + " )" );
    }

    EventGenerator.prototype.addRemove = function( obj ) {
        this._add( "t.remove( " + tojson( obj ) + " )" );
    }

    EventGenerator.prototype.addUpdate = function( objOld, objNew ) {
        this._add( "t.update( " + tojson( objOld ) + ", " + tojson( objNew ) + " )" );
    }
    
    EventGenerator.prototype.addCheckCount = function( count, query, shouldPrint, checkQuery ) {
        query = query || {};
        shouldPrint = shouldPrint || false;
        checkQuery = checkQuery || false;
        var action = "assert.eq( " + count + ", t.count( " + tojson( query ) + " ) );"
        if ( checkQuery ) {
            action += " assert.eq( " + count + ", t.find( " + tojson( query ) + " ).toArray().length );"
        }
        if ( shouldPrint ) {
            action += " print( me + ' ' + " + count + " );";
        }
        this._add( action );
    }
    
    EventGenerator.prototype.getEvents = function() {
        return this.events;
    }
    
    EventGenerator.dispatch = function() {
        var args = argumentsToArray( arguments );
        var me = args.shift();
        var collectionName = args.shift();
        var host = args.shift();
        var m = new Mongo( host );
        var t = m.getDB( "test" )[ collectionName ];
        for( var i in args ) {
            sleep( args[ i ][ 0 ] );
            eval( args[ i ][ 1 ] );
        }
    }
    
    // Helper class for running tests in parallel.  It assembles a set of tests
    // and then calls assert.parallelests to run them.
    ParallelTester = function() {
        this.params = new Array();
    }
    
    ParallelTester.prototype.add = function( fun, args ) {
        args = args || [];
        args.unshift( fun );
        this.params.push( args );
    }
    
    ParallelTester.prototype.run = function( msg, newScopes ) {
        newScopes = newScopes || false;
        assert.parallelTests( this.params, msg, newScopes );
    }
    
    // creates lists of tests from jstests dir in a format suitable for use by
    // ParallelTester.fileTester.  The lists will be in random order.
    // n: number of lists to split these tests into
    ParallelTester.createJstestsLists = function( n ) {
        var params = new Array();
        for( var i = 0; i < n; ++i ) {
            params.push( [] );
        }

        var makeKeys = function( a ) {
            var ret = {};
            for( var i in a ) {
                ret[ a[ i ] ] = 1;
            }
            return ret;
        }
        
        // some tests can't run in parallel with most others
        var skipTests = makeKeys( [ "jstests/dbadmin.js",
                                   "jstests/repair.js",
                                   "jstests/cursor8.js",
                                   "jstests/recstore.js",
                                   "jstests/extent.js",
                                   "jstests/indexb.js",
                                   "jstests/profile1.js",
                                   "jstests/mr3.js",
                                   "jstests/indexh.js",
                                   "jstests/apitest_db.js",
                                   "jstests/evalb.js",
                                   "jstests/evald.js",
                                   "jstests/evalf.js",
                                   "jstests/killop.js",
                                   "jstests/run_program1.js",
                                   "jstests/notablescan.js",
                                   "jstests/drop2.js",
                                   "jstests/dropdb_race.js",
                                   "jstests/fsync2.js", // May be placed in serialTestsArr once SERVER-4243 is fixed.
                                   "jstests/bench_test1.js",
                                   "jstests/padding.js",
                                   "jstests/queryoptimizera.js",
                                   "jstests/loglong.js",// log might overflow before 
                                                        // this has a chance to see the message
                                   "jstests/connections_opened.js" // counts connections, globally
                                  ] );
        
        // some tests can't be run in parallel with each other
        var serialTestsArr = [ "jstests/fsync.js"
//                              ,"jstests/fsync2.js" // SERVER-4243
                              ];
        var serialTests = makeKeys( serialTestsArr );
        
        params[ 0 ] = serialTestsArr;
        
        var files = listFiles("jstests");
        files = Array.shuffle( files );
        
        var i = 0;
        files.forEach(
                      function(x) {
                      
                      if ( ( /[\/\\]_/.test(x.name) ) ||
                          ( ! /\.js$/.test(x.name ) ) ||
                          ( x.name in skipTests ) ||
                          ( x.name in serialTests ) ||
                          ! /\.js$/.test(x.name ) ){ 
                      print(" >>>>>>>>>>>>>>> skipping " + x.name);
                      return;
                      }
                      
                      params[ i % n ].push( x.name );
                      ++i;
                      }
        );
        
        // randomize ordering of the serialTests
        params[ 0 ] = Array.shuffle( params[ 0 ] );
        
        for( var i in params ) {
            params[ i ].unshift( i );
        }
        
        return params;
    }
    
    // runs a set of test files
    // first argument is an identifier for this tester, remaining arguments are file names
    ParallelTester.fileTester = function() {
        var args = argumentsToArray( arguments );
        var suite = args.shift();
        args.forEach(
                     function( x ) {
                     print("         S" + suite + " Test : " + x + " ...");
                     var time = Date.timeFunc( function() { load(x); }, 1);
                     print("         S" + suite + " Test : " + x + " " + time + "ms" );
                     }
                     );        
    }
    
    // params: array of arrays, each element of which consists of a function followed
    // by zero or more arguments to that function.  Each function and its arguments will
    // be called in a separate thread.
    // msg: failure message
    // newScopes: if true, each thread starts in a fresh scope
    assert.parallelTests = function( params, msg, newScopes ) {
        newScopes = newScopes || false;
        var wrapper = function( fun, argv ) {
                   eval (
                         "var z = function() {" +
                         "var __parallelTests__fun = " + fun.toString() + ";" +
                         "var __parallelTests__argv = " + tojson( argv ) + ";" +
                         "var __parallelTests__passed = false;" +
                         "try {" +
                            "__parallelTests__fun.apply( 0, __parallelTests__argv );" +
                            "__parallelTests__passed = true;" +
                         "} catch ( e ) {" +
                            "print( '********** Parallel Test FAILED: ' + tojson(e) );" +
                         "}" +
                         "return __parallelTests__passed;" +
                         "}"
                         );
            return z;
        }
        var runners = new Array();
        for( var i in params ) {
            var param = params[ i ];
            var test = param.shift();
            var t;
            if ( newScopes )
                t = new ScopedThread( wrapper( test, param ) );
            else
                t = new Thread( wrapper( test, param ) );
            runners.push( t );
        }
        
        runners.forEach( function( x ) { x.start(); } );
        var nFailed = 0;
        // v8 doesn't like it if we exit before all threads are joined (SERVER-529)
        runners.forEach( function( x ) { if( !x.returnData() ) { ++nFailed; } } );        
        assert.eq( 0, nFailed, msg );
    }
}

shellPrint = function( x ){
    it = x;
    if ( x != undefined )
        shellPrintHelper( x );
    
    if ( db ){
        var e = db.getPrevError();
        if ( e.err ) {
            if ( e.nPrev <= 1 )
                print( "error on last call: " + tojson( e.err ) );
            else
                print( "an error " + tojson( e.err ) + " occurred " + e.nPrev + " operations back in the command invocation" );
        }
        db.resetError();
    }
}

printjson = function(x){
    print( tojson( x ) );
}

printjsononeline = function(x){
    print( tojsononeline( x ) );
}

if ( typeof TestData == "undefined" ){
    TestData = undefined
}

jsTestName = function(){
    if( TestData ) return TestData.testName
    return "__unknown_name__"
}

jsTestFile = function(){
    if( TestData ) return TestData.testFile
    return "__unknown_file__"
}

jsTestPath = function(){
    if( TestData ) return TestData.testPath
    return "__unknown_path__"
}

var _jsTestOptions = { enableTestCommands : true }; // Test commands should be enabled by default

jsTestOptions = function(){
    if( TestData ) {
        return Object.merge(_jsTestOptions,
                            { noJournal : TestData.noJournal,
                              noJournalPrealloc : TestData.noJournalPrealloc,
                              auth : TestData.auth,
                              keyFile : TestData.keyFile,
                              authUser : "__system",
                              authPassword : TestData.keyFileData,
                              adminUser : TestData.adminUser || "admin",
                              adminPassword : TestData.adminPassword || "password" });
    }
    return _jsTestOptions;
}

setJsTestOption = function(name, value) {
    _jsTestOptions[name] = value;
}

jsTestLog = function(msg){
    print( "\n\n----\n" + msg + "\n----\n\n" )
}

jsTest = {}

jsTest.name = jsTestName
jsTest.file = jsTestFile
jsTest.path = jsTestPath
jsTest.options = jsTestOptions
jsTest.setOption = setJsTestOption
jsTest.log = jsTestLog

jsTest.dir = function(){
    return jsTest.path().replace( /\/[^\/]+$/, "/" )
}

jsTest.randomize = function( seed ) {
    if( seed == undefined ) seed = new Date().getTime()
    Random.srand( seed )
    print( "Random seed for test : " + seed ) 
}

/**
* Adds a user to the admin DB on the given connection. This is only used for running the test suite
* with authentication enabled.
*/
jsTest.addAuth = function(conn) {
    // Get a connection over localhost so that the first user can be added.
    var localconn = conn;
    if ( localconn.host.indexOf('localhost') != 0 ) {
        print( 'Getting locahost connection instead of ' + conn + ' to add first admin user' );
        var hosts = conn.host.split(',');
        for ( var i = 0; i < hosts.length; i++ ) {
            hosts[i] = 'localhost:' + hosts[i].split(':')[1];
        }
        localconn = new Mongo(hosts.join(','));
    }
    print ("Adding admin user on connection: " + localconn);
    return localconn.getDB('admin').addUser(jsTestOptions().adminUser, jsTestOptions().adminPassword,
                                            false, 'majority', 60000);
}

jsTest.authenticate = function(conn) {
    if (!jsTest.options().auth && !jsTest.options().keyFile) {
        conn.authenticated = true;
        return true;
    }

    try {
        jsTest.attempt({timeout:5000, sleepTime:1000, desc: "Authenticating connection: " + conn},
                       function() {
                           // Set authenticated to stop an infinite recursion from getDB calling
                           // back into authenticate.
                           conn.authenticated = true;
                           print ("Authenticating to admin database as " +
                                  jsTestOptions().adminUser + " with mechanism " +
                                  DB.prototype._defaultAuthenticationMechanism +
                                  " on connection: " + conn);
                           conn.authenticated = conn.getDB('admin').auth({
                               user: jsTestOptions().adminUser,
                               pwd: jsTestOptions().adminPassword
                           });
                           return conn.authenticated;
                       });
    } catch (e) {
        print("Caught exception while authenticating connection: " + tojson(e));
        conn.authenticated = false;
    }
    return conn.authenticated;
}

jsTest.authenticateNodes = function(nodes) {
    jsTest.attempt({timeout:30000, desc: "Authenticate to nodes: " + nodes}, function() {
        for (var i = 0; i < nodes.length; i++) {
            // Don't try to authenticate to arbiters
            res = nodes[i].getDB("admin").runCommand({replSetGetStatus: 1});
            if(res.myState == 7) {
                continue;
            }
            if(jsTest.authenticate(nodes[i]) != 1) {
                return false;
            }
        }
        return true;
    });
}

jsTest.isMongos = function(conn) {
    return conn.getDB('admin').isMaster().msg=='isdbgrid';
}

// Pass this method a function to call repeatedly until
// that function returns true. Example:
//   attempt({timeout: 20000, desc: "get master"}, function() { // return false until success })
jsTest.attempt = function( opts, func ) {
    var timeout = opts.timeout || 1000;
    var tries   = 0;
    var sleepTime = opts.sleepTime || 2000;
    var result = null;
    var context = opts.context || this;

    while((result = func.apply(context)) == false) {
        tries += 1;
        sleep(sleepTime);
        if( tries * sleepTime > timeout) {
            throw('[' + opts['desc'] + ']' + " timed out after " + timeout + "ms ( " + tries + " tries )");
        }
    }

    return result;
}

replSetMemberStatePrompt = function() {
    var state = '';
    var stateInfo = db.getSiblingDB( 'admin' ).runCommand( { replSetGetStatus:1, forShell:1 } );
    if ( stateInfo.ok ) {
        // Report the self member's stateStr if it's present.
        stateInfo.members.forEach( function( member ) {
                                      if ( member.self ) {
                                          state = member.stateStr;
                                      }
                                  } );
        // Otherwise fall back to reporting the numeric myState field (mongodb 1.6).
        if ( !state ) {
            state = stateInfo.myState;
        }
        state = '' + stateInfo.set + ':' + state;
    }
    else {
        var info = stateInfo.info;
        if ( info && info.length < 20 ) {
            state = info; // "mongos", "configsvr"
        }
    }
    return state + '> ';
}

shellPrintHelper = function (x) {
    if (typeof (x) == "undefined") {
        // Make sure that we have a db var before we use it
        // TODO: This implicit calling of GLE can cause subtle, hard to track issues - remove?
        if (__callLastError && typeof( db ) != "undefined" && db.getMongo ) {
            __callLastError = false;
            // explicit w:1 so that replset getLastErrorDefaults aren't used here which would be bad.
            var err = db.getLastError(1);
            if (err != null) {
                print(err);
            }
        }
        return;
    }

    if (x == __magicNoPrint)
        return;

    if (x == null) {
        print("null");
        return;
    }

    if (typeof x != "object")
        return print(x);

    var p = x.shellPrint;
    if (typeof p == "function")
        return x.shellPrint();

    var p = x.tojson;
    if (typeof p == "function")
        print(x.tojson());
    else
        print(tojson(x));
}

shellAutocomplete = function ( /*prefix*/ ) { // outer scope function called on init. Actual function at end

    var universalMethods = "constructor prototype toString valueOf toLocaleString hasOwnProperty propertyIsEnumerable".split( ' ' );

    var builtinMethods = {}; // uses constructor objects as keys
    builtinMethods[Array] = "length concat join pop push reverse shift slice sort splice unshift indexOf lastIndexOf every filter forEach map some".split( ' ' );
    builtinMethods[Boolean] = "".split( ' ' ); // nothing more than universal methods
    builtinMethods[Date] = "getDate getDay getFullYear getHours getMilliseconds getMinutes getMonth getSeconds getTime getTimezoneOffset getUTCDate getUTCDay getUTCFullYear getUTCHours getUTCMilliseconds getUTCMinutes getUTCMonth getUTCSeconds getYear parse setDate setFullYear setHours setMilliseconds setMinutes setMonth setSeconds setTime setUTCDate setUTCFullYear setUTCHours setUTCMilliseconds setUTCMinutes setUTCMonth setUTCSeconds setYear toDateString toGMTString toLocaleDateString toLocaleTimeString toTimeString toUTCString UTC".split( ' ' );
    builtinMethods[Math] = "E LN2 LN10 LOG2E LOG10E PI SQRT1_2 SQRT2 abs acos asin atan atan2 ceil cos exp floor log max min pow random round sin sqrt tan".split( ' ' );
    builtinMethods[Number] = "MAX_VALUE MIN_VALUE NEGATIVE_INFINITY POSITIVE_INFINITY toExponential toFixed toPrecision".split( ' ' );
    builtinMethods[RegExp] = "global ignoreCase lastIndex multiline source compile exec test".split( ' ' );
    builtinMethods[String] = "length charAt charCodeAt concat fromCharCode indexOf lastIndexOf match replace search slice split substr substring toLowerCase toUpperCase".split( ' ' );
    builtinMethods[Function] = "call apply".split( ' ' );
    builtinMethods[Object] = "bsonsize".split( ' ' );

    builtinMethods[Mongo] = "find update insert remove".split( ' ' );
    builtinMethods[BinData] = "hex base64 length subtype".split( ' ' );

    var extraGlobals = "Infinity NaN undefined null true false decodeURI decodeURIComponent encodeURI encodeURIComponent escape eval isFinite isNaN parseFloat parseInt unescape Array Boolean Date Math Number RegExp String print load gc MinKey MaxKey Mongo NumberInt NumberLong ObjectId DBPointer UUID BinData HexData MD5 Map Timestamp".split( ' ' );

    var isPrivate = function( name ) {
        if ( shellAutocomplete.showPrivate ) return false;
        if ( name == '_id' ) return false;
        if ( name[0] == '_' ) return true;
        if ( name[name.length - 1] == '_' ) return true; // some native functions have an extra name_ method
        return false;
    }

    var customComplete = function( obj ) {
        try {
            if ( obj.__proto__.constructor.autocomplete ) {
                var ret = obj.constructor.autocomplete( obj );
                if ( ret.constructor != Array ) {
                    print( "\nautocompleters must return real Arrays" );
                    return [];
                }
                return ret;
            } else {
                return [];
            }
        } catch ( e ) {
            // print( e ); // uncomment if debugging custom completers
            return [];
        }
    }

    var worker = function( prefix ) {
        var global = ( function() { return this; } ).call(); // trick to get global object

        var curObj = global;
        var parts = prefix.split( '.' );
        for ( var p = 0; p < parts.length - 1; p++ ) { // doesn't include last part
            curObj = curObj[parts[p]];
            if ( curObj == null )
                return [];
        }

        var lastPrefix = parts[parts.length - 1] || '';
        var lastPrefixLowercase = lastPrefix.toLowerCase()
        var beginning = parts.slice( 0, parts.length - 1 ).join( '.' );
        if ( beginning.length )
            beginning += '.';

        var possibilities = new Array().concat(
            universalMethods,
            Object.keySet( curObj ),
            Object.keySet( curObj.__proto__ ),
            builtinMethods[curObj] || [], // curObj is a builtin constructor
            builtinMethods[curObj.__proto__.constructor] || [], // curObj is made from a builtin constructor
            curObj == global ? extraGlobals : [],
            customComplete( curObj )
        );

        var noDuplicates = {}; // see http://dreaminginjavascript.wordpress.com/2008/08/22/eliminating-duplicates/
        for ( var i = 0; i < possibilities.length; i++ ) {
            var p = possibilities[i];
            if ( typeof ( curObj[p] ) == "undefined" && curObj != global ) continue; // extraGlobals aren't in the global object
            if ( p.length == 0 || p.length < lastPrefix.length ) continue;
            if ( lastPrefix[0] != '_' && isPrivate( p ) ) continue;
            if ( p.match( /^[0-9]+$/ ) ) continue; // don't array number indexes
            if ( p.substr( 0, lastPrefix.length ).toLowerCase() != lastPrefixLowercase ) continue;

            var completion = beginning + p;
            if ( curObj[p] && curObj[p].constructor == Function && p != 'constructor' )
                completion += '(';

            noDuplicates[completion] = 0;
        }

        var ret = [];
        for ( var i in noDuplicates )
            ret.push( i );

        return ret;
    }

    // this is the actual function that gets assigned to shellAutocomplete
    return function( prefix ) {
        try {
            __autocomplete__ = worker( prefix ).sort();
        } catch ( e ) {
            print( "exception during autocomplete: " + tojson( e.message ) );
            __autocomplete__ = [];
        }
    }
} ();

shellAutocomplete.showPrivate = false; // toggle to show (useful when working on internals)

shellHelper = function( command , rest , shouldPrint ){
    command = command.trim();
    var args = rest.trim().replace(/\s*;$/,"").split( "\s+" );
    
    if ( ! shellHelper[command] )
        throw "no command [" + command + "]";
    
    var res = shellHelper[command].apply( null , args );
    if ( shouldPrint ){
        shellPrintHelper( res );
    }
    return res;
}

shellHelper.use = function (dbname) {
    var s = "" + dbname;
    if (s == "") {
        print("bad use parameter");
        return;
    }
    db = db.getMongo().getDB(dbname);
    print("switched to db " + db.getName());
}

shellHelper.set = function (str) {
    if (str == "") {
        print("bad use parameter");
        return;
    }
    tokens = str.split(" ");
    param = tokens[0];
    value = tokens[1];
    
    if ( value == undefined ) value = true;
    // value comes in as a string..
    if ( value == "true" ) value = true;
    if ( value == "false" ) value = false;

    if (param == "verbose") {
        _verboseShell = value;
    }
    print("set " + param + " to " + value);
}

shellHelper.it = function(){
    if ( typeof( ___it___ ) == "undefined" || ___it___ == null ){
        print( "no cursor" );
        return;
    }
    shellPrintHelper( ___it___ );
}

shellHelper.show = function (what) {
    assert(typeof what == "string");

    var args = what.split( /\s+/ );
    what = args[0]
    args = args.splice(1)

    if (what == "profile") {
        if (db.system.profile.count() == 0) {
            print("db.system.profile is empty");
            print("Use db.setProfilingLevel(2) will enable profiling");
            print("Use db.system.profile.find() to show raw profile entries");
        }
        else {
            print();
            db.system.profile.find({ millis: { $gt: 0} }).sort({ $natural: -1 }).limit(5).forEach(
                function (x) { 
                    print("" + x.op + "\t" + x.ns + " " + x.millis + "ms " + String(x.ts).substring(0, 24)); 
                    var l = "";
                    for ( var z in x ){
                        if ( z == "op" || z == "ns" || z == "millis" || z == "ts" )
                            continue;
                        
                        var val = x[z];
                        var mytype = typeof(val);
                        
                        if ( mytype == "string" || 
                             mytype == "number" )
                            l += z + ":" + val + " ";
                        else if ( mytype == "object" ) 
                            l += z + ":" + tojson(val ) + " ";
                        else if ( mytype == "boolean" )
                            l += z + " ";
                        else
                            l += z + ":" + val + " ";

                    }
                    print( l );
                    print("\n"); 
                }
            )
        }
        return "";
    }

    if (what == "users") {
        db.system.users.find().forEach(printjson);
        return "";
    }

    if (what == "collections" || what == "tables") {
        db.getCollectionNames().forEach(function (x) { print(x) });
        return "";
    }

    if (what == "dbs" || what == "databases") {
        var dbs = db.getMongo().getDBs();
        var size = {};
        dbs.databases.forEach(function (x) { size[x.name] = x.sizeOnDisk; });
        var names = dbs.databases.map(function (z) { return z.name; }).sort();
        names.forEach(function (n) {
            if (size[n] > 1) {
                print(n + "\t" + size[n] / 1024 / 1024 / 1024 + "GB");
            } else {
                print(n + "\t(empty)");
            }
        });
        //db.getMongo().getDBNames().sort().forEach(function (x) { print(x) });
        return "";
    }
    
    if (what == "log" ) {
        var n = "global";
        if ( args.length > 0 )
            n = args[0]
        
        var res = db.adminCommand( { getLog : n } )
        for ( var i=0; i<res.log.length; i++){
            print( res.log[i] )
        }
        return ""
    }

    if (what == "logs" ) {
        var res = db.adminCommand( { getLog : "*" } )
        for ( var i=0; i<res.names.length; i++){
            print( res.names[i] )
        }
        return ""
    }

    if (what == "startupWarnings" ) {
        var dbDeclared, ex;
        try {
            // !!db essentially casts db to a boolean
            // Will throw a reference exception if db hasn't been declared.
            dbDeclared = !!db;
        } catch (ex) {
            dbDeclared = false;
        }
        if (dbDeclared) {
            var res = db.adminCommand( { getLog : "startupWarnings" } );
            if ( res.ok ) {
                if (res.log.length == 0) {
                    return "";
                }
                print( "Server has startup warnings: " );
                for ( var i=0; i<res.log.length; i++){
                    print( res.log[i] )
                }
                return "";
            } else {
                print("Error while trying to show server startup warnings: " + res.errmsg);
                return "";
            }
        } else {
            print("Cannot show startupWarnings, \"db\" is not set");
            return "";
        }
    }

    throw "don't know how to show [" + what + "]";

}

Math.sigFig = function( x , N ){
    if ( ! N ){
        N = 3;
    }
    var p = Math.pow( 10, N - Math.ceil( Math.log( Math.abs(x) ) / Math.log( 10 )) );
    return Math.round(x*p)/p;
}

Random = function() {}

// set random seed
Random.srand = function( s ) { _srand( s ); }

// random number 0 <= r < 1
Random.rand = function() { return _rand(); }

// random integer 0 <= r < n
Random.randInt = function( n ) { return Math.floor( Random.rand() * n ); }

Random.setRandomSeed = function( s ) {
    s = s || new Date().getTime();
    print( "setting random seed: " + s );
    Random.srand( s );
}

// generate a random value from the exponential distribution with the specified mean
Random.genExp = function( mean ) {
    var r = Random.rand();
    if ( r == 0 ) {
        r = Random.rand();
        if ( r == 0 ) {
            r = 0.000001;
        }
    }
    return -Math.log( r ) * mean;
}

Geo = {};
Geo.distance = function( a , b ){
    var ax = null;
    var ay = null;
    var bx = null;
    var by = null;
    
    for ( var key in a ){
        if ( ax == null )
            ax = a[key];
        else if ( ay == null )
            ay = a[key];
    }
    
    for ( var key in b ){
        if ( bx == null )
            bx = b[key];
        else if ( by == null )
            by = b[key];
    }

    return Math.sqrt( Math.pow( by - ay , 2 ) + 
                      Math.pow( bx - ax , 2 ) );
}

Geo.sphereDistance = function( a , b ){
    var ax = null;
    var ay = null;
    var bx = null;
    var by = null;
    
    // TODO swap order of x and y when done on server
    for ( var key in a ){
        if ( ax == null )
            ax = a[key] * (Math.PI/180);
        else if ( ay == null )
            ay = a[key] * (Math.PI/180);
    }
    
    for ( var key in b ){
        if ( bx == null )
            bx = b[key] * (Math.PI/180);
        else if ( by == null )
            by = b[key] * (Math.PI/180);
    }

    var sin_x1=Math.sin(ax), cos_x1=Math.cos(ax);
    var sin_y1=Math.sin(ay), cos_y1=Math.cos(ay);
    var sin_x2=Math.sin(bx), cos_x2=Math.cos(bx);
    var sin_y2=Math.sin(by), cos_y2=Math.cos(by);

    var cross_prod = 
        (cos_y1*cos_x1 * cos_y2*cos_x2) +
        (cos_y1*sin_x1 * cos_y2*sin_x2) +
        (sin_y1        * sin_y2);

    if (cross_prod >= 1 || cross_prod <= -1){
        // fun with floats
        assert( Math.abs(cross_prod)-1 < 1e-6 );
        return cross_prod > 0 ? 0 : Math.PI;
    }

    return Math.acos(cross_prod);
}

rs = function () { return "try rs.help()"; }

rs.help = function () {
    print("\trs.status()                     { replSetGetStatus : 1 } checks repl set status");
    print("\trs.initiate()                   { replSetInitiate : null } initiates set with default settings");
    print("\trs.initiate(cfg)                { replSetInitiate : cfg } initiates set with configuration cfg");
    print("\trs.conf()                       get the current configuration object from local.system.replset");
    print("\trs.reconfig(cfg)                updates the configuration of a running replica set with cfg (disconnects)");
    print("\trs.add(hostportstr)             add a new member to the set with default attributes (disconnects)");
    print("\trs.add(membercfgobj)            add a new member to the set with extra attributes (disconnects)");
    print("\trs.addArb(hostportstr)          add a new member which is arbiterOnly:true (disconnects)");
    print("\trs.stepDown([secs])             step down as primary (momentarily) (disconnects)");
    print("\trs.syncFrom(hostportstr)        make a secondary to sync from the given member");
    print("\trs.freeze(secs)                 make a node ineligible to become primary for the time specified");
    print("\trs.remove(hostportstr)          remove a host from the replica set (disconnects)");
    print("\trs.slaveOk()                    shorthand for db.getMongo().setSlaveOk()");
    print();
    print("\tdb.isMaster()                   check who is primary");
    print("\tdb.printReplicationInfo()       check oplog size and time range");
    print();
    print("\treconfiguration helpers disconnect from the database so the shell will display");
    print("\tan error, even if the command succeeds.");
    print("\tsee also http://<mongod_host>:28017/_replSet for additional diagnostic info");
}
rs.slaveOk = function (value) { return db.getMongo().setSlaveOk(value); }
rs.status = function () { return db._adminCommand("replSetGetStatus"); }
rs.isMaster = function () { return db.isMaster(); }
rs.initiate = function (c) { return db._adminCommand({ replSetInitiate: c }); }
rs._runCmd = function (c) {
    // after the command, catch the disconnect and reconnect if necessary
    var res = null;
    try {
        res = db.adminCommand(c);
    }
    catch (e) {
        if (("" + e).indexOf("error doing query") >= 0) {
            // closed connection.  reconnect.
            db.getLastErrorObj();
            var o = db.getLastErrorObj();
            if (o.ok) {
                print("reconnected to server after rs command (which is normal)");
            }
            else {
                printjson(o);
            }
        }
        else {
            print("shell got exception during repl set operation: " + e);
            print("in some circumstances, the primary steps down and closes connections on a reconfig");
        }
        return "";
    }
    return res;
}
rs.reconfig = function (cfg, options) {
    cfg.version = rs.conf().version + 1;
    cmd = { replSetReconfig: cfg };
    for (var i in options) {
        cmd[i] = options[i];
    }
    return this._runCmd(cmd);
}
rs.add = function (hostport, arb) {
    var cfg = hostport;

    var local = db.getSisterDB("local");
    assert(local.system.replset.count() <= 1, "error: local.system.replset has unexpected contents");
    var c = local.system.replset.findOne();
    assert(c, "no config object retrievable from local.system.replset");

    c.version++;

    var max = 0;
    for (var i in c.members)
        if (c.members[i]._id > max) max = c.members[i]._id;
    if (isString(hostport)) {
        cfg = { _id: max + 1, host: hostport };
        if (arb)
            cfg.arbiterOnly = true;
    }
    c.members.push(cfg);
    return this._runCmd({ replSetReconfig: c });
}
rs.syncFrom = function (host) { return db._adminCommand({replSetSyncFrom : host}); };
rs.stepDown = function (secs) { return db._adminCommand({ replSetStepDown:(secs === undefined) ? 60:secs}); }
rs.freeze = function (secs) { return db._adminCommand({replSetFreeze:secs}); }
rs.addArb = function (hn) { return this.add(hn, true); }
rs.conf = function () { return db.getSisterDB("local").system.replset.findOne(); }
rs.config = function () { return rs.conf(); }

rs.remove = function (hn) {
    var local = db.getSisterDB("local");
    assert(local.system.replset.count() <= 1, "error: local.system.replset has unexpected contents");
    var c = local.system.replset.findOne();
    assert(c, "no config object retrievable from local.system.replset");
    c.version++;

    for (var i in c.members) {
        if (c.members[i].host == hn) {
            c.members.splice(i, 1);
            return db._adminCommand({ replSetReconfig : c});
        }
    }

    return "error: couldn't find "+hn+" in "+tojson(c.members);
};

rs.debug = {};

rs.debug.nullLastOpWritten = function(primary, secondary) {
    var p = connect(primary+"/local");
    var s = connect(secondary+"/local");
    s.getMongo().setSlaveOk();

    var secondToLast = s.oplog.rs.find().sort({$natural : -1}).limit(1).next();
    var last = p.runCommand({findAndModify : "oplog.rs",
                             query : {ts : {$gt : secondToLast.ts}},
                             sort : {$natural : 1},
                             update : {$set : {op : "n"}}});

    if (!last.value.o || !last.value.o._id) {
        print("couldn't find an _id?");
    }
    else {
        last.value.o = {_id : last.value.o._id};
    }

    print("nulling out this op:");
    printjson(last);
};

rs.debug.getLastOpWritten = function(server) {
    var s = db.getSisterDB("local");
    if (server) {
        s = connect(server+"/local");
    }
    s.getMongo().setSlaveOk();

    return s.oplog.rs.find().sort({$natural : -1}).limit(1).next();
};


help = shellHelper.help = function (x) {
    if (x == "mr") {
        print("\nSee also http://dochub.mongodb.org/core/mapreduce");
        print("\nfunction mapf() {");
        print("  // 'this' holds current document to inspect");
        print("  emit(key, value);");
        print("}");
        print("\nfunction reducef(key,value_array) {");
        print("  return reduced_value;");
        print("}");
        print("\ndb.mycollection.mapReduce(mapf, reducef[, options])");
        print("\noptions");
        print("{[query : <query filter object>]");
        print(" [, sort : <sort the query.  useful for optimization>]");
        print(" [, limit : <number of objects to return from collection>]");
        print(" [, out : <output-collection name>]");
        print(" [, keeptemp: <true|false>]");
        print(" [, finalize : <finalizefunction>]");
        print(" [, scope : <object where fields go into javascript global scope >]");
        print(" [, verbose : true]}\n");
        return;
    } else if (x == "connect") {
        print("\nNormally one specifies the server on the mongo shell command line.  Run mongo --help to see those options.");
        print("Additional connections may be opened:\n");
        print("    var x = new Mongo('host[:port]');");
        print("    var mydb = x.getDB('mydb');");
        print("  or");
        print("    var mydb = connect('host[:port]/mydb');");
        print("\nNote: the REPL prompt only auto-reports getLastError() for the shell command line connection.\n");
        return;
    }
    else if (x == "keys") {
        print("Tab completion and command history is available at the command prompt.\n");
        print("Some emacs keystrokes are available too:");
        print("  Ctrl-A start of line");
        print("  Ctrl-E end of line");
        print("  Ctrl-K del to end of line");
        print("\nMulti-line commands");
        print("You can enter a multi line javascript expression.  If parens, braces, etc. are not closed, you will see a new line ");
        print("beginning with '...' characters.  Type the rest of your expression.  Press Ctrl-C to abort the data entry if you");
        print("get stuck.\n");
    }
    else if (x == "misc") {
        print("\tb = new BinData(subtype,base64str)  create a BSON BinData value");
        print("\tb.subtype()                         the BinData subtype (0..255)");
        print("\tb.length()                          length of the BinData data in bytes");
        print("\tb.hex()                             the data as a hex encoded string");
        print("\tb.base64()                          the data as a base 64 encoded string");
        print("\tb.toString()");
        print();
        print("\tb = HexData(subtype,hexstr)         create a BSON BinData value from a hex string");
        print("\tb = UUID(hexstr)                    create a BSON BinData value of UUID subtype");
        print("\tb = MD5(hexstr)                     create a BSON BinData value of MD5 subtype");
        print("\t\"hexstr\"                            string, sequence of hex characters (no 0x prefix)");
        print();
        print("\to = new ObjectId()                  create a new ObjectId");
        print("\to.getTimestamp()                    return timestamp derived from first 32 bits of the OID");
        print("\to.isObjectId");
        print("\to.toString()");
        print("\to.equals(otherid)");
        print();
        print("\td = ISODate()                       like Date() but behaves more intuitively when used");
        print("\td = ISODate('YYYY-MM-DD hh:mm:ss')    without an explicit \"new \" prefix on construction");
        return;
    }
    else if (x == "admin") {
        print("\tls([path])                      list files");
        print("\tpwd()                           returns current directory");
        print("\tlistFiles([path])               returns file list");
        print("\thostname()                      returns name of this host");
        print("\tcat(fname)                      returns contents of text file as a string");
        print("\tremoveFile(f)                   delete a file or directory");
        print("\tload(jsfilename)                load and execute a .js file");
        print("\trun(program[, args...])         spawn a program and wait for its completion");
        print("\trunProgram(program[, args...])  same as run(), above");
        print("\tsleep(m)                        sleep m milliseconds");
        print("\tgetMemInfo()                    diagnostic");
        return;
    }
    else if (x == "test") {
        print("\tstartMongodEmpty(args)        DELETES DATA DIR and then starts mongod");
        print("\t                              returns a connection to the new server");
        print("\tstartMongodTest(port,dir,options)");
        print("\t                              DELETES DATA DIR");
        print("\t                              automatically picks port #s starting at 27000 and increasing");
        print("\t                              or you can specify the port as the first arg");
        print("\t                              dir is /data/db/<port>/ if not specified as the 2nd arg");
        print("\t                              returns a connection to the new server");
        print("\tresetDbpath(dirpathstr)       deletes everything under the dir specified including subdirs");
        print("\tstopMongoProgram(port[, signal])");
        return;
    }
    else if (x == "") {
        print("\t" + "db.help()                    help on db methods");
        print("\t" + "db.mycoll.help()             help on collection methods");
        print("\t" + "sh.help()                    sharding helpers");
        print("\t" + "rs.help()                    replica set helpers");
        print("\t" + "help admin                   administrative help");
        print("\t" + "help connect                 connecting to a db help");
        print("\t" + "help keys                    key shortcuts");
        print("\t" + "help misc                    misc things to know");
        print("\t" + "help mr                      mapreduce");
        print();
        print("\t" + "show dbs                     show database names");
        print("\t" + "show collections             show collections in current database");
        print("\t" + "show users                   show users in current database");
        print("\t" + "show profile                 show most recent system.profile entries with time >= 1ms");
        print("\t" + "show logs                    show the accessible logger names");
        print("\t" + "show log [name]              prints out the last segment of log in memory, 'global' is default");
        print("\t" + "use <db_name>                set current database");
        print("\t" + "db.foo.find()                list objects in collection foo");
        print("\t" + "db.foo.find( { a : 1 } )     list objects in foo where a == 1");
        print("\t" + "it                           result of the last line evaluated; use to further iterate");
        print("\t" + "DBQuery.shellBatchSize = x   set default number of items to display on shell");
        print("\t" + "exit                         quit the mongo shell");
    }
    else
        print("unknown help option");
}