1 files changed, 125 insertions, 0 deletions
diff --git a/src/mongo/gotools/mongotop/mongotop.go b/src/mongo/gotools/mongotop/mongotop.go
new file mode 100644
index 00000000000..0743d25d4e0
--- /dev/null
+++ b/src/mongo/gotools/mongotop/mongotop.go
@@ -0,0 +1,125 @@
+// Package mongotop provides a method to track the amount of time a MongoDB instance spends reading and writing data.
+package mongotop
+
+import (
+	"fmt"
+	"github.com/mongodb/mongo-tools/common/db"
+	"github.com/mongodb/mongo-tools/common/log"
+	"github.com/mongodb/mongo-tools/common/options"
+	"time"
+)
+
+// MongoTop is a container for the user-specified options and
+// internal state used for running mongotop.
+type MongoTop struct {
+	// Generic mongo tool options
+	Options *options.ToolOptions
+
+	// Mongotop-specific output options
+	OutputOptions *Output
+
+	// for connecting to the db
+	SessionProvider *db.SessionProvider
+
+	// Length of time to sleep between each polling.
+	Sleeptime time.Duration
+
+	previousServerStatus *ServerStatus
+	previousTop          *Top
+}
+
+func (mt *MongoTop) runDiff() (outDiff FormattableDiff, err error) {
+	session, err := mt.SessionProvider.GetSession()
+	if err != nil {
+		return nil, err
+	}
+	defer session.Close()
+	session.SetSocketTimeout(0)
+
+	var currentServerStatus ServerStatus
+	var currentTop Top
+	commandName := "top"
+	var dest interface{} = &currentTop
+	if mt.OutputOptions.Locks {
+		commandName = "serverStatus"
+		dest = &currentServerStatus
+	}
+	err = session.DB("admin").Run(commandName, dest)
+	if err != nil {
+		mt.previousServerStatus = nil
+		mt.previousTop = nil
+		return nil, err
+	}
+	if mt.OutputOptions.Locks {
+		if currentServerStatus.Locks == nil {
+			return nil, fmt.Errorf("server does not support reporting lock information")
+		}
+		for _, ns := range currentServerStatus.Locks {
+			if ns.AcquireCount != nil {
+				return nil, fmt.Errorf("server does not support reporting lock information")
+			}
+		}
+		if mt.previousServerStatus != nil {
+			serverStatusDiff := currentServerStatus.Diff(*mt.previousServerStatus)
+			outDiff = serverStatusDiff
+		}
+		mt.previousServerStatus = &currentServerStatus
+	} else {
+		if mt.previousTop != nil {
+			topDiff := currentTop.Diff(*mt.previousTop)
+			outDiff = topDiff
+		}
+		mt.previousTop = &currentTop
+	}
+	return outDiff, nil
+}
+
+// Run executes the mongotop program.
+func (mt *MongoTop) Run() error {
+
+	connURL := mt.Options.Host
+	if connURL == "" {
+		connURL = "127.0.0.1"
+	}
+	if mt.Options.Port != "" {
+		connURL = connURL + ":" + mt.Options.Port
+	}
+
+	hasData := false
+	numPrinted := 0
+
+	for {
+		if mt.OutputOptions.RowCount > 0 && numPrinted > mt.OutputOptions.RowCount {
+			return nil
+		}
+		numPrinted++
+		diff, err := mt.runDiff()
+		if err != nil {
+			// If this is the first time trying to poll the server and it fails,
+			// just stop now instead of trying over and over.
+			if !hasData {
+				return err
+			}
+
+			log.Logvf(log.Always, "Error: %v\n", err)
+			time.Sleep(mt.Sleeptime)
+		}
+
+		// if this is the first time and the connection is successful, print
+		// the connection message
+		if !hasData && !mt.OutputOptions.Json {
+			log.Logvf(log.Always, "connected to: %v\n", connURL)
+		}
+
+		hasData = true
+
+		if diff != nil {
+			if mt.OutputOptions.Json {
+				fmt.Println(diff.JSON())
+			} else {
+				fmt.Println(diff.Grid())
+			}
+		}
+		time.Sleep(mt.Sleeptime)
+	}
+}