Add a collector for NFS client statistics.

This change adds a new collector called "nfs" that parses the contents
of /proc/net/rpc/nfs and turns it into metrics. It can be used to
inspect the number of operations per type, but also to keep an eye on an
extraneous number of retransmissions, which may indicate connectivity
issues.

I've picked the name "nfs", as most operating systems use "nfs" for the
client component and "nfsd" as the server component. If we want to add
stats for the NFS server as well, we'd better call such a collector
"nfsd".

1 files changed, 176 insertions, 0 deletions

diff --git a/collector/nfs_linux.go b/collector/nfs_linux.go
new file mode 100644
index 0000000..70083d3
--- /dev/null
+++ b/collector/nfs_linux.go
@@ -0,0 +1,176 @@
+// Copyright 2016 The Prometheus Authors
+// 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 collector
+
+import (
+        "errors"
+        "io/ioutil"
+        "os"
+        "regexp"
+        "strconv"
+        "strings"
+
+        "github.com/prometheus/client_golang/prometheus"
+        "github.com/prometheus/common/log"
+)
+
+var (
+        netLineRE  = regexp.MustCompile(`^net \d+ (\d+) (\d+) (\d+)$`)
+        rpcLineRE  = regexp.MustCompile(`^rpc (\d+) (\d+) (\d+)$`)
+        procLineRE = regexp.MustCompile(`^proc(\d+) \d+ (\d+( \d+)*)$`)
+
+        nfsProcedures = map[string][]string{
+                "2": []string{
+                        "null", "getattr", "setattr", "root", "lookup",
+                        "readlink", "read", "writecache", "write", "create",
+                        "remove", "rename", "link", "symlink", "mkdir",
+                        "rmdir", "readdir", "statfs",
+                },
+                "3": []string{
+                        "null", "getattr", "setattr", "lookup", "access",
+                        "readlink", "read", "write", "create", "mkdir",
+                        "symlink", "mknod", "remove", "rmdir", "rename",
+                        "link", "readdir", "readdirplus", "fsstat", "fsinfo",
+                        "pathconf", "commit",
+                },
+                "4": []string{
+                        "null", "read", "write", "commit", "open",
+                        "open_confirm", "open_noattr", "open_downgrade",
+                        "close", "setattr", "fsinfo", "renew", "setclientid",
+                        "setclientid_confirm", "lock", "lockt", "locku",
+                        "access", "getattr", "lookup", "lookup_root", "remove",
+                        "rename", "link", "symlink", "create", "pathconf",
+                        "statfs", "readlink", "readdir", "server_caps",
+                        "delegreturn", "getacl", "setacl", "fs_locations",
+                        "release_lockowner", "secinfo", "fsid_present",
+                        "exchange_id", "create_session", "destroy_session",
+                        "sequence", "get_lease_time", "reclaim_complete",
+                        "layoutget", "getdeviceinfo", "layoutcommit",
+                        "layoutreturn", "secinfo_no_name", "test_stateid",
+                        "free_stateid", "getdevicelist",
+                        "bind_conn_to_session", "destroy_clientid", "seek",
+                        "allocate", "deallocate", "layoutstats", "clone",
+                        "copy",
+                },
+        }
+
+        nfsNetReadsDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "net_reads"),
+                "Number of reads at the network layer.",
+                []string{"protocol"},
+                nil,
+        )
+        nfsNetConnectionsDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "net_connections"),
+                "Number of connections at the network layer.",
+                []string{"protocol"},
+                nil,
+        )
+
+        nfsRpcOperationsDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "rpc_operations"),
+                "Number of RPCs performed.",
+                nil,
+                nil,
+        )
+        nfsRpcRetransmissionsDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "rpc_retransmissions"),
+                "Number of RPC transmissions performed.",
+                nil,
+                nil,
+        )
+        nfsRpcAuthenticationRefreshesDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "rpc_authentication_refreshes"),
+                "Number of RPC authentication refreshes performed.",
+                nil,
+                nil,
+        )
+
+        nfsProceduresDesc = prometheus.NewDesc(
+                prometheus.BuildFQName(Namespace, "nfs", "procedures"),
+                "Number of NFS procedures invoked.",
+                []string{"version", "procedure"},
+                nil,
+        )
+)
+
+type nfsCollector struct{}
+
+func init() {
+        Factories["nfs"] = NewNfsCollector
+}
+
+func NewNfsCollector() (Collector, error) {
+        return &nfsCollector{}, nil
+}
+
+func (c *nfsCollector) Update(ch chan<- prometheus.Metric) (err error) {
+        statsFile := procFilePath("net/rpc/nfs")
+        content, err := ioutil.ReadFile(statsFile)
+        if err != nil {
+                if os.IsNotExist(err) {
+                        log.Debugf("Not collecting NFS statistics, as %s does not exist: %s", statsFile)
+                        return nil
+                }
+                return err
+        }
+
+        for _, line := range strings.Split(string(content), "\n") {
+                if fields := netLineRE.FindStringSubmatch(line); fields != nil {
+                        value, _ := strconv.ParseFloat(fields[1], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsNetReadsDesc, prometheus.CounterValue,
+                                value, "udp")
+
+                        value, _ = strconv.ParseFloat(fields[2], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsNetReadsDesc, prometheus.CounterValue,
+                                value, "tcp")
+
+                        value, _ = strconv.ParseFloat(fields[3], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsNetConnectionsDesc, prometheus.CounterValue,
+                                value, "tcp")
+                } else if fields := rpcLineRE.FindStringSubmatch(line); fields != nil {
+                        value, _ := strconv.ParseFloat(fields[1], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsRpcOperationsDesc,
+                                prometheus.CounterValue, value)
+
+                        value, _ = strconv.ParseFloat(fields[2], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsRpcRetransmissionsDesc,
+                                prometheus.CounterValue, value)
+
+                        value, _ = strconv.ParseFloat(fields[3], 64)
+                        ch <- prometheus.MustNewConstMetric(
+                                nfsRpcAuthenticationRefreshesDesc,
+                                prometheus.CounterValue, value)
+                } else if fields := procLineRE.FindStringSubmatch(line); fields != nil {
+                        version := fields[1]
+                        for procedure, count := range strings.Split(fields[2], " ") {
+                                value, _ := strconv.ParseFloat(count, 64)
+                                ch <- prometheus.MustNewConstMetric(
+                                        nfsProceduresDesc,
+                                        prometheus.CounterValue,
+                                        value,
+                                        version,
+                                        nfsProcedures[version][procedure])
+                        }
+                } else if line != "" {
+                        return errors.New("Failed to parse line: " + line)
+                }
+        }
+        return nil
+}