Refactor NFS client collector (#816)

* Update vendor github.com/prometheus/procfs/...

* Refactor NFS collector

Use new procfs library to parse NFS client stats.

* Ignore nfs proc file not existing.

* Refactor with reflection to walk the structs.

4 files changed, 32 insertions, 23 deletions

diff --git a/vendor/github.com/prometheus/procfs/fs.go b/vendor/github.com/prometheus/procfs/fs.go
index 36c1586..65f0922 100644
--- a/vendor/github.com/prometheus/procfs/fs.go
+++ b/vendor/github.com/prometheus/procfs/fs.go
@@ -46,8 +46,8 @@ func (fs FS) XFSStats() (*xfs.Stats, error) {
         return xfs.ParseStats(f)
 }
 
-// NFSdClientRPCStats retrieves NFS daemon RPC statistics.
-func (fs FS) NFSdClientRPCStats() (*nfs.ClientRPCStats, error) {
+// NFSClientRPCStats retrieves NFS client RPC statistics.
+func (fs FS) NFSClientRPCStats() (*nfs.ClientRPCStats, error) {
         f, err := os.Open(fs.Path("net/rpc/nfs"))
         if err != nil {
                 return nil, err
diff --git a/vendor/github.com/prometheus/procfs/nfs/parse.go b/vendor/github.com/prometheus/procfs/nfs/parse.go
index 3aa3256..8f568f0 100644
--- a/vendor/github.com/prometheus/procfs/nfs/parse.go
+++ b/vendor/github.com/prometheus/procfs/nfs/parse.go
@@ -178,8 +178,17 @@ func parseV3Stats(v []uint64) (V3Stats, error) {
 
 func parseClientV4Stats(v []uint64) (ClientV4Stats, error) {
         values := int(v[0])
-        if len(v[1:]) != values || values < 59 {
-                return ClientV4Stats{}, fmt.Errorf("invalid V4Stats line %q", v)
+        if len(v[1:]) != values {
+                return ClientV4Stats{}, fmt.Errorf("invalid ClientV4Stats line %q", v)
+        }
+
+        // This function currently supports mapping 59 NFS v4 client stats.  Older
+        // kernels may emit fewer stats, so we must detect this and pad out the
+        // values to match the expected slice size.
+        if values < 59 {
+                newValues := make([]uint64, 60)
+                copy(newValues, v)
+                v = newValues
         }
 
         return ClientV4Stats{
diff --git a/vendor/github.com/prometheus/procfs/nfs/parse_nfs.go b/vendor/github.com/prometheus/procfs/nfs/parse_nfs.go
index b5c0b15..c0d3a5a 100644
--- a/vendor/github.com/prometheus/procfs/nfs/parse_nfs.go
+++ b/vendor/github.com/prometheus/procfs/nfs/parse_nfs.go
@@ -32,12 +32,12 @@ func ParseClientRPCStats(r io.Reader) (*ClientRPCStats, error) {
                 parts := strings.Fields(scanner.Text())
                 // require at least <key> <value>
                 if len(parts) < 2 {
-                        return nil, fmt.Errorf("invalid NFSd metric line %q", line)
+                        return nil, fmt.Errorf("invalid NFS metric line %q", line)
                 }
 
                 values, err := util.ParseUint64s(parts[1:])
                 if err != nil {
-                        return nil, fmt.Errorf("error parsing NFSd metric line: %s", err)
+                        return nil, fmt.Errorf("error parsing NFS metric line: %s", err)
                 }
 
                 switch metricLine := parts[0]; metricLine {
@@ -52,15 +52,15 @@ func ParseClientRPCStats(r io.Reader) (*ClientRPCStats, error) {
                 case "proc4":
                         stats.ClientV4Stats, err = parseClientV4Stats(values)
                 default:
-                        return nil, fmt.Errorf("unknown NFSd metric line %q", metricLine)
+                        return nil, fmt.Errorf("unknown NFS metric line %q", metricLine)
                 }
                 if err != nil {
-                        return nil, fmt.Errorf("errors parsing NFSd metric line: %s", err)
+                        return nil, fmt.Errorf("errors parsing NFS metric line: %s", err)
                 }
         }
 
         if err := scanner.Err(); err != nil {
-                return nil, fmt.Errorf("error scanning NFSd file: %s", err)
+                return nil, fmt.Errorf("error scanning NFS file: %s", err)
         }
 
         return stats, nil
diff --git a/vendor/vendor.json b/vendor/vendor.json
index 20391c0..4b43706 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -161,40 +161,40 @@
                         "revisionTime": "2018-01-10T21:49:58Z"
                 },
                 {
-                        "checksumSHA1": "lolK0h7LSVERIX8zLyVQ/+7wEyA=",
+                        "checksumSHA1": "Qvc01kv3ttHV2P2+J68g9ioU4Qs=",
                         "path": "github.com/prometheus/procfs",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
                         "checksumSHA1": "O64FotgWPYIpl3m2gvTEPIem+xg=",
                         "path": "github.com/prometheus/procfs/bcache",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
                         "checksumSHA1": "lv9rIcjbVEGo8AT1UCUZXhXrfQc=",
                         "path": "github.com/prometheus/procfs/internal/util",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
-                        "checksumSHA1": "BXJH5h2ri8SU5qC6kkDvTIGCky4=",
+                        "checksumSHA1": "EekY1iRG9JY74mDD0jsbFCWbAFs=",
                         "path": "github.com/prometheus/procfs/nfs",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
                         "checksumSHA1": "wMhQkA/xQw3Q8eI+PIAjFmS94Qo=",
                         "path": "github.com/prometheus/procfs/sysfs",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
                         "checksumSHA1": "yItvTQLUVqm/ArLEbvEhqG0T5a0=",
                         "path": "github.com/prometheus/procfs/xfs",
-                        "revision": "cb4147076ac75738c9a7d279075a253c0cc5acbd",
-                        "revisionTime": "2018-01-25T13:30:57Z"
+                        "revision": "282c8707aa210456a825798969cc27edda34992a",
+                        "revisionTime": "2018-02-12T14:59:26Z"
                 },
                 {
                         "checksumSHA1": "ySaT8G3I3y4MmnoXOYAAX0rC+p8=",