refactor: snmp to use gosmi

internal/snmp/config.go

@@ -10,6 +10,8 @@ type ClientConfig struct {
 	Retries int             `toml:"retries"`
 	// Values: 1, 2, 3
 	Version uint8 `toml:"version"`
+	// Path to mib files
+	Path []string `toml:"path"`
 
 	// Parameters for Version 1 & 2
 	Community string `toml:"community"`

internal/snmp/translate.go

@@ -0,0 +1,183 @@
+package snmp
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/influxdata/telegraf"
+	"github.com/sleepinggenius2/gosmi"
+	"github.com/sleepinggenius2/gosmi/types"
+)
+
+// must init, append path for each directory, load module for every file
+// or gosmi will fail without saying why
+func LoadMibsFromPath(paths []string, log telegraf.Logger) error {
+	gosmi.Init()
+	var folders []string
+	for _, mibPath := range paths {
+		gosmi.AppendPath(mibPath)
+		folders = append(folders, mibPath)
+		err := filepath.Walk(mibPath, func(path string, info os.FileInfo, err error) error {
+			// symlinks are files so we need to double check if any of them are folders
+			// Will check file vs directory later on
+			if info.Mode()&os.ModeSymlink != 0 {
+				link, err := os.Readlink(path)
+				if err != nil {
+					log.Warnf("Bad symbolic link %v", link)
+				}
+				folders = append(folders, link)
+			}
+			return nil
+		})
+		if err != nil {
+			return fmt.Errorf("Filepath could not be walked %v", err)
+		}
+		for _, folder := range folders {
+			err := filepath.Walk(folder, func(path string, info os.FileInfo, err error) error {
+				// checks if file or directory
+				if info.IsDir() {
+					gosmi.AppendPath(path)
+				} else if info.Mode()&os.ModeSymlink == 0 {
+					_, err := gosmi.LoadModule(info.Name())
+					if err != nil {
+						log.Warnf("Module could not be loaded %v", err)
+					}
+				}
+				return nil
+			})
+			if err != nil {
+				return fmt.Errorf("Filepath could not be walked %v", err)
+			}
+		}
+		folders = []string{}
+	}
+	return nil
+}
+
+// The following is for snmp_trap
+type MibEntry struct {
+	MibName string
+	OidText string
+}
+
+func TrapLookup(oid string) (e MibEntry, err error) {
+	var node gosmi.SmiNode
+	node, err = gosmi.GetNodeByOID(types.OidMustFromString(oid))
+
+	// ensure modules are loaded or node will be empty (might not error)
+	if err != nil {
+		return e, err
+	}
+
+	e.OidText = node.RenderQualified()
+
+	i := strings.Index(e.OidText, "::")
+	if i == -1 {
+		return e, fmt.Errorf("not found")
+	}
+	e.MibName = e.OidText[:i]
+	e.OidText = e.OidText[i+2:]
+	return e, nil
+}
+
+// The following is for snmp
+
+func GetIndex(oidNum string, mibPrefix string) (col []string, tagOids map[string]struct{}, err error) {
+	// first attempt to get the table's tags
+	tagOids = map[string]struct{}{}
+
+	// mimcks grabbing INDEX {} that is returned from snmptranslate -Td MibName
+	node, err := gosmi.GetNodeByOID(types.OidMustFromString(oidNum))
+
+	if err != nil {
+		return []string{}, map[string]struct{}{}, fmt.Errorf("getting submask: %w", err)
+	}
+
+	for _, index := range node.GetIndex() {
+		//nolint:staticcheck //assaignment to nil map to keep backwards compatibilty
+		tagOids[mibPrefix+index.Name] = struct{}{}
+	}
+
+	// grabs all columns from the table
+	// mimmicks grabbing everything returned from snmptable -Ch -Cl -c public 127.0.0.1 oidFullName
+	col = node.GetRow().AsTable().ColumnOrder
+
+	return col, tagOids, nil
+}
+
+//nolint:revive //Too many return variable but necessary
+func SnmpTranslateCall(oid string) (mibName string, oidNum string, oidText string, conversion string, err error) {
+	var out gosmi.SmiNode
+	var end string
+	if strings.ContainsAny(oid, "::") {
+		// split given oid
+		// for example RFC1213-MIB::sysUpTime.0
+		s := strings.Split(oid, "::")
+		// node becomes sysUpTime.0
+		node := s[1]
+		if strings.ContainsAny(node, ".") {
+			s = strings.Split(node, ".")
+			// node becomes sysUpTime
+			node = s[0]
+			end = "." + s[1]
+		}
+
+		out, err = gosmi.GetNode(node)
+		if err != nil {
+			return oid, oid, oid, oid, err
+		}
+
+		oidNum = "." + out.RenderNumeric() + end
+	} else if strings.ContainsAny(oid, "abcdefghijklnmopqrstuvwxyz") {
+		//handle mixed oid ex. .iso.2.3
+		s := strings.Split(oid, ".")
+		for i := range s {
+			if strings.ContainsAny(s[i], "abcdefghijklmnopqrstuvwxyz") {
+				out, err = gosmi.GetNode(s[i])
+				if err != nil {
+					return oid, oid, oid, oid, err
+				}
+				s[i] = out.RenderNumeric()
+			}
+		}
+		oidNum = strings.Join(s, ".")
+		out, _ = gosmi.GetNodeByOID(types.OidMustFromString(oidNum))
+	} else {
+		out, err = gosmi.GetNodeByOID(types.OidMustFromString(oid))
+		oidNum = oid
+		// ensure modules are loaded or node will be empty (might not error)
+		// do not return the err as the oid is numeric and telegraf can continue
+		//nolint:nilerr
+		if err != nil || out.Name == "iso" {
+			return oid, oid, oid, oid, nil
+		}
+	}
+
+	tc := out.GetSubtree()
+
+	for i := range tc {
+		// case where the mib doesn't have a conversion so Type struct will be nil
+		// prevents seg fault
+		if tc[i].Type == nil {
+			break
+		}
+		switch tc[i].Type.Name {
+		case "MacAddress", "PhysAddress":
+			conversion = "hwaddr"
+		case "InetAddressIPv4", "InetAddressIPv6", "InetAddress", "IPSIpAddress":
+			conversion = "ipaddr"
+		}
+	}
+
+	oidText = out.RenderQualified()
+	i := strings.Index(oidText, "::")
+	if i == -1 {
+		return "", oid, oid, oid, fmt.Errorf("not found")
+	}
+	mibName = oidText[:i]
+	oidText = oidText[i+2:] + end
+
+	return mibName, oidNum, oidText, conversion, nil
+}

plugins/inputs/snmp/README.md

@@ -4,19 +4,10 @@ The `snmp` input plugin uses polling to gather metrics from SNMP agents.
 Support for gathering individual OIDs as well as complete SNMP tables is
 included.
 
-## Prerequisites
+## Note about Paths
 
-This plugin uses the `snmptable` and `snmptranslate` programs from the
-[net-snmp][] project.  These tools will need to be installed into the `PATH` in
-order to be located.  Other utilities from the net-snmp project may be useful
-for troubleshooting, but are not directly used by the plugin.
-
-These programs will load available MIBs on the system.  Typically the default
-directory for MIBs is `/usr/share/snmp/mibs`, but if your MIBs are in a
-different location you may need to make the paths known to net-snmp.  The
-location of these files can be configured in the `snmp.conf` or via the
-`MIBDIRS` environment variable. See [`man 1 snmpcmd`][man snmpcmd] for more
-information.
+Path is a global variable, separate snmp instances will append the specified
+path onto the global path variable
 
 ## Configuration
 
@@ -38,6 +29,9 @@ information.
   ## SNMP version; can be 1, 2, or 3.
   # version = 2
 
+  ## Path to mib files
+  # path = ["/usr/share/snmp/mibs"]
+
   ## SNMP community string.
   # community = "public"
 
@@ -260,7 +254,7 @@ oid = "CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortEntPhyIndex"
 
 Partial result (removed agent_host and host columns from all following outputs in this section):
 
-```shell
+```text
 > ciscoPower,index=1.2 EntPhyIndex=1002i,PortPwrConsumption=6643i 1621460628000000000
 > ciscoPower,index=1.6 EntPhyIndex=1006i,PortPwrConsumption=10287i 1621460628000000000
 > ciscoPower,index=1.5 EntPhyIndex=1005i,PortPwrConsumption=8358i 1621460628000000000
@@ -313,7 +307,7 @@ is_tag = true
 
 Result:
 
-```shell
+```text
 > ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/2,index=1.2 EntPhyIndex=1002i,PortPwrConsumption=6643i 1621461148000000000
 > ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/6,index=1.6 EntPhyIndex=1006i,PortPwrConsumption=10287i 1621461148000000000
 > ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/5,index=1.5 EntPhyIndex=1005i,PortPwrConsumption=8358i 1621461148000000000
@@ -357,7 +351,5 @@ interface,agent_host=127.0.0.1,ifDescr=eth0,ifIndex=2,source=example.org ifAdmin
 interface,agent_host=127.0.0.1,ifDescr=lo,ifIndex=1,source=example.org ifAdminStatus=1i,ifInDiscards=0i,ifInErrors=0i,ifInNUcastPkts=0i,ifInOctets=51555569i,ifInUcastPkts=339097i,ifInUnknownProtos=0i,ifLastChange=0i,ifMtu=65536i,ifOperStatus=1i,ifOutDiscards=0i,ifOutErrors=0i,ifOutNUcastPkts=0i,ifOutOctets=51555569i,ifOutQLen=0i,ifOutUcastPkts=339097i,ifSpecific=".0.0",ifSpeed=10000000i,ifType=24i 1575509815000000000
 ```
 
-[net-snmp]: http://www.net-snmp.org/
-[man snmpcmd]: http://net-snmp.sourceforge.net/docs/man/snmpcmd.html#lbAK
 [metric filtering]: /docs/CONFIGURATION.md#metric-filtering
 [metric]: /docs/METRICS.md