snmp: use a shared global translation cache
Prevents the same data from being looked up multiple times. Also prevents multiple simultaneous lookups. closes #2115 closes #2104
This commit is contained in:
Patrick Hemmer
committed by
Cameron Sparr
Cameron Sparr
parent
91143dda1a
commit
b58926dd26
@@ -8,6 +8,7 @@ import (
|
||||
"os/exec"
|
||||
"strconv"
|
||||
"strings"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
"github.com/influxdata/telegraf"
|
||||
@@ -199,65 +200,22 @@ func (t *Table) init() error {
|
||||
return nil
|
||||
}
|
||||
|
||||
// init() populates Fields if a table OID is provided.
|
||||
// initBuild initializes the table if it has an OID configured. If so, the
|
||||
// net-snmp tools will be used to look up the OID and auto-populate the table's
|
||||
// fields.
|
||||
func (t *Table) initBuild() error {
|
||||
if t.Oid == "" {
|
||||
return nil
|
||||
}
|
||||
|
||||
mibName, _, oidText, _, err := snmpTranslate(t.Oid)
|
||||
_, _, oidText, fields, err := snmpTable(t.Oid)
|
||||
if err != nil {
|
||||
return Errorf(err, "translating %s", t.Oid)
|
||||
return Errorf(err, "initializing table %s", t.Oid)
|
||||
}
|
||||
if t.Name == "" {
|
||||
t.Name = oidText
|
||||
}
|
||||
mibPrefix := mibName + "::"
|
||||
oidFullName := mibPrefix + oidText
|
||||
|
||||
// first attempt to get the table's tags
|
||||
tagOids := map[string]struct{}{}
|
||||
// We have to guess that the "entry" oid is `t.Oid+".1"`. snmptable and snmptranslate don't seem to have a way to provide the info.
|
||||
if out, err := execCmd("snmptranslate", "-Td", oidFullName+".1"); err == nil {
|
||||
lines := bytes.Split(out, []byte{'\n'})
|
||||
for _, line := range lines {
|
||||
if !bytes.HasPrefix(line, []byte(" INDEX")) {
|
||||
continue
|
||||
}
|
||||
|
||||
i := bytes.Index(line, []byte("{ "))
|
||||
if i == -1 { // parse error
|
||||
continue
|
||||
}
|
||||
line = line[i+2:]
|
||||
i = bytes.Index(line, []byte(" }"))
|
||||
if i == -1 { // parse error
|
||||
continue
|
||||
}
|
||||
line = line[:i]
|
||||
for _, col := range bytes.Split(line, []byte(", ")) {
|
||||
tagOids[mibPrefix+string(col)] = struct{}{}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// this won't actually try to run a query. The `-Ch` will just cause it to dump headers.
|
||||
out, err := execCmd("snmptable", "-Ch", "-Cl", "-c", "public", "127.0.0.1", oidFullName)
|
||||
if err != nil {
|
||||
return Errorf(err, "getting table columns for %s", t.Oid)
|
||||
}
|
||||
cols := bytes.SplitN(out, []byte{'\n'}, 2)[0]
|
||||
if len(cols) == 0 {
|
||||
return fmt.Errorf("unable to get columns for table %s", t.Oid)
|
||||
}
|
||||
for _, col := range bytes.Split(cols, []byte{' '}) {
|
||||
if len(col) == 0 {
|
||||
continue
|
||||
}
|
||||
col := string(col)
|
||||
_, isTag := tagOids[mibPrefix+col]
|
||||
t.Fields = append(t.Fields, Field{Name: col, Oid: mibPrefix + col, IsTag: isTag})
|
||||
}
|
||||
t.Fields = append(t.Fields, fields...)
|
||||
|
||||
return nil
|
||||
}
|
||||
@@ -841,8 +799,131 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
|
||||
return nil, fmt.Errorf("invalid conversion type '%s'", conv)
|
||||
}
|
||||
|
||||
type snmpTableCache struct {
|
||||
mibName string
|
||||
oidNum string
|
||||
oidText string
|
||||
fields []Field
|
||||
err error
|
||||
}
|
||||
|
||||
var snmpTableCaches map[string]snmpTableCache
|
||||
var snmpTableCachesLock sync.Mutex
|
||||
|
||||
// snmpTable resolves the given OID as a table, providing information about the
|
||||
// table and fields within.
|
||||
func snmpTable(oid string) (mibName string, oidNum string, oidText string, fields []Field, err error) {
|
||||
snmpTableCachesLock.Lock()
|
||||
if snmpTableCaches == nil {
|
||||
snmpTableCaches = map[string]snmpTableCache{}
|
||||
}
|
||||
|
||||
var stc snmpTableCache
|
||||
var ok bool
|
||||
if stc, ok = snmpTableCaches[oid]; !ok {
|
||||
stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err = snmpTableCall(oid)
|
||||
snmpTableCaches[oid] = stc
|
||||
}
|
||||
|
||||
snmpTableCachesLock.Unlock()
|
||||
return stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err
|
||||
}
|
||||
|
||||
func snmpTableCall(oid string) (mibName string, oidNum string, oidText string, fields []Field, err error) {
|
||||
mibName, oidNum, oidText, _, err = snmpTranslate(oid)
|
||||
if err != nil {
|
||||
return "", "", "", nil, Errorf(err, "translating")
|
||||
}
|
||||
|
||||
mibPrefix := mibName + "::"
|
||||
oidFullName := mibPrefix + oidText
|
||||
|
||||
// first attempt to get the table's tags
|
||||
tagOids := map[string]struct{}{}
|
||||
// We have to guess that the "entry" oid is `oid+".1"`. snmptable and snmptranslate don't seem to have a way to provide the info.
|
||||
if out, err := execCmd("snmptranslate", "-Td", oidFullName+".1"); err == nil {
|
||||
lines := bytes.Split(out, []byte{'\n'})
|
||||
for _, line := range lines {
|
||||
if !bytes.HasPrefix(line, []byte(" INDEX")) {
|
||||
continue
|
||||
}
|
||||
|
||||
i := bytes.Index(line, []byte("{ "))
|
||||
if i == -1 { // parse error
|
||||
continue
|
||||
}
|
||||
line = line[i+2:]
|
||||
i = bytes.Index(line, []byte(" }"))
|
||||
if i == -1 { // parse error
|
||||
continue
|
||||
}
|
||||
line = line[:i]
|
||||
for _, col := range bytes.Split(line, []byte(", ")) {
|
||||
tagOids[mibPrefix+string(col)] = struct{}{}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// this won't actually try to run a query. The `-Ch` will just cause it to dump headers.
|
||||
out, err := execCmd("snmptable", "-Ch", "-Cl", "-c", "public", "127.0.0.1", oidFullName)
|
||||
if err != nil {
|
||||
return "", "", "", nil, Errorf(err, "getting table columns")
|
||||
}
|
||||
cols := bytes.SplitN(out, []byte{'\n'}, 2)[0]
|
||||
if len(cols) == 0 {
|
||||
return "", "", "", nil, fmt.Errorf("could not find any columns in table")
|
||||
}
|
||||
for _, col := range bytes.Split(cols, []byte{' '}) {
|
||||
if len(col) == 0 {
|
||||
continue
|
||||
}
|
||||
col := string(col)
|
||||
_, isTag := tagOids[mibPrefix+col]
|
||||
fields = append(fields, Field{Name: col, Oid: mibPrefix + col, IsTag: isTag})
|
||||
}
|
||||
|
||||
return mibName, oidNum, oidText, fields, err
|
||||
}
|
||||
|
||||
type snmpTranslateCache struct {
|
||||
mibName string
|
||||
oidNum string
|
||||
oidText string
|
||||
conversion string
|
||||
err error
|
||||
}
|
||||
|
||||
var snmpTranslateCachesLock sync.Mutex
|
||||
var snmpTranslateCaches map[string]snmpTranslateCache
|
||||
|
||||
// snmpTranslate resolves the given OID.
|
||||
func snmpTranslate(oid string) (mibName string, oidNum string, oidText string, conversion string, err error) {
|
||||
snmpTranslateCachesLock.Lock()
|
||||
if snmpTranslateCaches == nil {
|
||||
snmpTranslateCaches = map[string]snmpTranslateCache{}
|
||||
}
|
||||
|
||||
var stc snmpTranslateCache
|
||||
var ok bool
|
||||
if stc, ok = snmpTranslateCaches[oid]; !ok {
|
||||
// This will result in only one call to snmptranslate running at a time.
|
||||
// We could speed it up by putting a lock in snmpTranslateCache and then
|
||||
// returning it immediately, and multiple callers would then release the
|
||||
// snmpTranslateCachesLock and instead wait on the individual
|
||||
// snmpTranlsation.Lock to release. But I don't know that the extra complexity
|
||||
// is worth it. Especially when it would slam the system pretty hard if lots
|
||||
// of lookups are being perfomed.
|
||||
|
||||
stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.err = snmpTranslateCall(oid)
|
||||
snmpTranslateCaches[oid] = stc
|
||||
}
|
||||
|
||||
snmpTranslateCachesLock.Unlock()
|
||||
|
||||
return stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.err
|
||||
}
|
||||
|
||||
func snmpTranslateCall(oid string) (mibName string, oidNum string, oidText string, conversion string, err error) {
|
||||
var out []byte
|
||||
if strings.ContainsAny(oid, ":abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ") {
|
||||
out, err = execCmd("snmptranslate", "-Td", "-Ob", oid)
|
||||
|
||||
Reference in New Issue
Block a user