Added status.json handler. (refs #2561)

diff --git a/services/keep/keep.go b/services/keep/keep.go
index adffaa477c46ab7bd5c9a3014794c77d34fc33a5..b96afff991864b567a5df91be4448c1629cf22b4 100644 (file)
--- a/services/keep/keep.go
+++ b/services/keep/keep.go
@@ -10,10 +10,10 @@ import (
        "log"
        "net/http"
        "os"
-       "os/exec"
        "path/filepath"
        "strconv"
        "strings"
+       "syscall"
        "time"
 )
 
@@ -69,6 +69,7 @@ func main() {
        rest.HandleFunc(`/{hash:[0-9a-f]{32}}`, PutBlockHandler).Methods("PUT")
        rest.HandleFunc(`/index`, IndexHandler).Methods("GET", "HEAD")
        rest.HandleFunc(`/index/{prefix:[0-9a-f]{0,32}}`, IndexHandler).Methods("GET", "HEAD")
+       rest.HandleFunc(`/status\.json`, StatusHandler).Methods("GET", "HEAD")
 
        // Tell the built-in HTTP server to direct all requests to the REST
        // router.
@@ -154,6 +155,80 @@ func IndexHandler(w http.ResponseWriter, req *http.Request) {
        w.Write([]byte(index))
 }
 
+// StatusHandler
+//     Responds to /status.json requests with the current node status,
+//     described in a JSON structure.
+//
+//     The data given in a status.json response includes:
+//        time - the time the status was last updated
+//        df   - the output of the most recent `df --block-size=1k`
+//        disk_devices - list of disk device files (i.e. /dev/(s|xv|h)d)
+//        dirs - an object describing Keep volumes, keyed on Keep volume dirs,
+//          each value is an object describing the status of that volume
+//            * status ("full [timestamp]" or "ok [timestamp]")
+//            * last_error
+//            * last_error_time
+//
+type VolumeStatus struct {
+       Space       string
+       LastErr     string
+       LastErrTime time.Time
+}
+
+type NodeStatus struct {
+       LastUpdate time.Time
+       DfOutput   string
+       DiskDev    []string
+       Volumes    map[string]VolumeStatus
+}
+
+func StatusHandler(w http.ResponseWriter, req *http.Request) {
+       st := new(NodeStatus)
+       st.LastUpdate = time.Now()
+
+       // Get a list of disk devices on this system.
+       st.DiskDev = make([]string, 1)
+       if devdir, err := os.Open("/dev"); err != nil {
+               log.Printf("StatusHandler: opening /dev: %s\n", err)
+       } else {
+               devs, err := devdir.Readdirnames(0)
+               if err == nil {
+                       for _, d := range devs {
+                               if strings.HasPrefix(d, "sd") ||
+                                       strings.HasPrefix(d, "hd") ||
+                                       strings.HasPrefix(d, "xvd") {
+                                       st.DiskDev = append(st.DiskDev, d)
+                               }
+                       }
+               } else {
+                       log.Printf("Readdirnames: %s", err)
+               }
+       }
+
+       for _, vol := range KeepVolumes {
+               st.Volumes[vol] = GetVolumeStatus(vol)
+       }
+}
+
+// GetVolumeStatus
+//     Returns a VolumeStatus describing the requested volume.
+func GetVolumeStatus(volume string) VolumeStatus {
+       var isfull, lasterr string
+       var lasterrtime time.Time
+
+       if IsFull(volume) {
+               isfull = fmt.Sprintf("full %d", time.Now().Unix())
+       } else {
+               isfull = fmt.Sprintf("ok %d", time.Now().Unix())
+       }
+
+       // Not implemented yet
+       lasterr = ""
+       lasterrtime = time.Unix(0, 0)
+
+       return VolumeStatus{isfull, lasterr, lasterrtime}
+}
+
 // IndexLocators
 //     Returns a string containing a list of locator ids found on this
 //     Keep server.  If {prefix} is given, return only those locator
@@ -373,32 +448,13 @@ func IsFull(volume string) (isFull bool) {
 //     Returns the amount of available disk space on VOLUME,
 //     as a number of 1k blocks.
 //
-func FreeDiskSpace(volume string) (free int, err error) {
-       // Run df to find out how much disk space is left.
-       cmd := exec.Command("df", "--block-size=1k", volume)
-       stdout, perr := cmd.StdoutPipe()
-       if perr != nil {
-               return 0, perr
+func FreeDiskSpace(volume string) (free uint64, err error) {
+       var fs syscall.Statfs_t
+       err = syscall.Statfs(volume, &fs)
+       if err == nil {
+               // Statfs output is not guaranteed to measure free
+               // space in terms of 1K blocks.
+               free = fs.Bavail * uint64(fs.Bsize) / 1024
        }
-       scanner := bufio.NewScanner(stdout)
-       if perr := cmd.Start(); err != nil {
-               return 0, perr
-       }
-
-       scanner.Scan() // skip header line of df output
-       scanner.Scan()
-
-       f := strings.Fields(scanner.Text())
-       if avail, err := strconv.Atoi(f[3]); err == nil {
-               free = avail
-       } else {
-               err = errors.New("bad df format: " + scanner.Text())
-       }
-
-       // Flush the df output and shut it down cleanly.
-       for scanner.Scan() {
-       }
-       cmd.Wait()
-
        return
 }