Go Node#

This node can execute a limited subset of Go code in a flow. The node uses the open source Scriggo project to execute Go code using a custom interpreter.


The Scriggo Go interpreter does not implement all of the Go specification and may behave unexpectedly when doing reflection or complex pointer operations. The Go node is useful for performing simple type-aware operations in a flow, not writing complex programs.


The Go flow node has some notable restrictions on what it can and can’t do:

  • No goroutines. The go keyword is disabled and the node cannot launch goroutines.

  • No reflection on custom types. The reflect package cannot handle types defined in your programs.

  • Limited libraries. You can only import libraries that are included in the searchagent. Full list at the end of this page.

  • No unsafe package and limited pointer operations. The unsafe package cannot be imported and pointer arithmetic will likely result in unexpected results.

  • No defer operation. Sorry, not implemented, do it like it’s C99!


  • Code, required: The Go code to run.

  • Outputs: a list of variables to be output from the program (see below).


The Go node can modify any value in the incoming payload. It can also create new items in the outgoing payload, but those new items must be listed in the Outputs config field.

Variables in the payload are accessed in Go code by using the Getter/Setter interface on the Payload variable exported in the gravwell package, e.g. gravwell.Payload.Set("foobar", 3.14159).

Debug Output#

All stdout or stderr output will be written to the Flow console log. This means including a println("hello mom!") will include hello mom! in the flow debug output.

Native Gravwell Package#

The Go flow node can import a package called gravwell that will allow access to flow specific functions and values. The gravwell package can almost be thought of as a “virtual” package because it simply maps global variables and some internal flow functionality to a package so that Go node programs can interact with flow variables.

The gravwell package exposes the following variables and functions:

Payload Getter and Setter#

One of the most useful variables in the gravwell package is the Payload variable which enables getting and setting natively typed values in the Flow payload. The Payload variable implements the following interface:

type Payload interface {
	Get(string) (interface{}, error)
	Set(string, interface{}) error

The Payload interface can get and set native types into the flow payload similar to the Javascript node or other logic nodes.


Defining a new struct type in your Go program and setting it into the flow Payload may result in undefined behavior, because that type information won’t make it outside the Go flow node.

Blocking Flow Execution#

If you call gravwell.Block(), further execution will be blocked–nodes downstream of the Go node will not be executed.

if payload.Get(`flow.Name`) == "foo" {

Other Package Types#






The scheduled start time for the flow. This time may be far in the past if the flow is backfilling missed runs.



The timestamp of the last run of this flow.



The scheduled time duration of a flow run. This repesents the time window the flow should cover for any queries.



The current flow ID.


func() *client.Client

Returns an active logged in client for use, client.Client docs available.


SetPersistentMap(mapName string, key string, value interface{})

Set a natively typed value into a persistent map that can be retrieved across runs.


GetPersistentMap(mapName string, key string) (value interface{})

Get a persistent map value from previous runs.


DeletePersistentMap(mapName, value string)

Delete a value from the persistent map.


PersistentMap(mapName string) map[string]interface{}

Get a complete persistent map.


Backup(wtr io.Writer, includeSS bool) (err error)

Create a new backup with a provided io.Writer.


BackupWithConfig(wtr io.Writer, cfg types.BackupConfig) (err error)

Create a new backup with the provided io.Writer and BackupConfig.


GetMacro(key string) (string, error)

Retrieve a system macro.


Systems() (map[string]types.SysInfo

Get a map of SysInfo structures using the system name as the map key.


Ingesters() (map[string]types.IngestStats, error)

Get a map of IngesterStats keyed by terminating indexer UUID.


Indexers() (map[string]types.IdxStats, error)

Get a map of IdxStats keyed by indexer UUID. This API call is expensive and returns the complete shard state systemwide.


IndexerStates() (map[string]string, error)

Get a map of indexer health states keyed by indexer UUID.


AddSelfTargetedNotification(id uint32, msg, link string, expires time.Time) error

Create a Gravwell notification.


GetResource(key string) ([]byte, error)

Get a Gravwell resource.


SetResource(key string, value []byte) (error)

Set a Gravwell resource.


ScheduledSearchInfo() ([]types.ScheduledSearch, error)

Get the list of ScheduledSearch structures for the current user.


GetSecret(name string) (string, error)

Retrieve a secret value. This is the complete secret value, so be careful with this call.


Below are a few basic examples of using the Go node to perform some specific operations that may be useful in a Flow.

Payload Modification#

This program shows how we grab a value from the flow payload, modify it, and put it back. The basic flow might look like the following:

package main

import (

var payload = gravwell.Payload

func main() {
	if name, err := payload.Get(`flow.Name`); err != nil {
		panic("Failed to get flow.Name")
	} else if err = payload.Set(`newName`, name.(string) + "is a better name"); err != nil {
		panic("failed to set new name")
	println("I suggested a better name")

Getting a Client#

This program shows how to get a handle on a client and then use it to perform some more complicated operations.

package main

import (

var payload = gravwell.Payload

func main() {
	cli := gravwell.GetClient()
	if cli == nil {
		panic("got a nil client")
	ver, err := cli.GetApiVersion()
	if err != nil {
	payload.Set("api-version", ver)
	println("I got API version", ver)

Getting Search Results#

In this flow we grab a search ID and then use a client to download the results and relay them out to a TCP socket. This example demonstrates using the Go node to attach to a native search type as well as export the data through an imported library function.

package main

import (



var payload = gravwell.Payload

func main() {
	cli := gravwell.GetClient()
	if cli == nil {
		panic("got a nil client")
	val, err := payload.Get(`search.ID`)
	if err != nil {
	id := fmt.Sprintf("%v", val)
	println("got id", id)
	conn, err := net.Dial("tcp", "")
	if err != nil {
	tr := types.TimeRange{} //blank for all time
	resp, err := cli.SearchDownloadRequest(id, `csv`, tr)
	if err != nil {
	n, err := io.Copy(conn, resp.Body)

	if err != nil {
	println("I sent", n, "bytes")

Available Libraries For Import#

Standard Library Packages#

  • archive/tar

  • archive/zip

  • bufio

  • bytes

  • compress/bzip2

  • compress/flate

  • compress/gzip

  • compress/lzw

  • compress/zlib

  • container/heap

  • container/list

  • container/ring

  • context

  • crypto

  • crypto/aes

  • crypto/cipher

  • crypto/des

  • crypto/dsa

  • crypto/ecdsa

  • crypto/elliptic

  • crypto/hmac

  • crypto/md5

  • crypto/rand

  • crypto/rc4

  • crypto/rsa

  • crypto/sha1

  • crypto/sha256

  • crypto/sha512

  • crypto/subtle

  • crypto/tls

  • crypto/x509

  • crypto/x509/pkix

  • debug/dwarf

  • debug/elf

  • debug/gosym

  • debug/macho

  • debug/pe

  • debug/plan9obj

  • encoding

  • encoding/ascii85

  • encoding/asn1

  • encoding/base32

  • encoding/base64

  • encoding/binary

  • encoding/csv

  • encoding/gob

  • encoding/hex

  • encoding/json

  • encoding/pem

  • encoding/xml

  • errors

  • expvar

  • flag

  • fmt

  • go/ast

  • go/build

  • go/constant

  • go/doc

  • go/format

  • go/importer

  • go/parser

  • go/printer

  • go/scanner

  • go/token

  • go/types

  • hash

  • hash/adler32

  • hash/crc32

  • hash/crc64

  • hash/fnv

  • hash/maphash

  • html

  • html/template

  • image

  • image/color

  • image/color/palette

  • image/draw

  • image/gif

  • image/jpeg

  • image/png

  • index/suffixarray

  • io

  • io/ioutil Excluding ReadDir ReadFile TempDir TempFile WriteFile

  • io/fs

  • math

  • math/big

  • math/bits

  • math/cmplx

  • math/rand

  • mime

  • mime/multipart

  • mime/quotedprintable

  • net/http/cgi

  • net/http/cookiejar

  • net/http/pprof

  • net/textproto

  • net/url

  • path

  • path/filepath

  • reflect

  • regexp

  • regexp/syntax

  • sort

  • strconv

  • strings

  • sync

  • sync/atomic

  • text/scanner

  • text/tabwriter

  • text/template

  • text/template/parse

  • time

  • unicode

  • unicode/utf16

  • unicode/utf8

Gravwell Library Packages#

  • github.com/gravwell/gravwell/v3/ingest

  • github.com/gravwell/gravwell/v3/ingest/entry

  • github.com/gravwell/gravwell/v3/ingest/config

  • github.com/gravwell/gravwell/v3/ingest/log

  • github.com/gravwell/gravwell/v3/client

  • github.com/gravwell/gravwell/v3/client/objlog

  • github.com/gravwell/gravwell/v3/client/types

  • github.com/gravwell/gravwell/v3/client/websocketRouter

  • github.com/gravwell/gravwell/v3/ipexist

  • github.com/gravwell/gravwell/v3/timegrinder

Third Party Packages#

  • github.com/BurntSushi/toml

  • github.com/Knetic/govaluate

  • github.com/Pallinder/go-randomdata AS randomdata

  • github.com/TylerBrock/colorjson

  • github.com/abadojack/whatlanggo

  • github.com/abiosoft/readline

  • github.com/auyer/steganography

  • github.com/blevesearch/segment

  • github.com/bndr/gotabulate

  • github.com/buger/jsonparser

  • github.com/crewjam/rfc5424

  • github.com/dchest/siphash

  • github.com/denisbrodbeck/machineid

  • github.com/dennwc/ioctl

  • github.com/go-openapi/strfmt

  • github.com/go-yaml/yaml

  • github.com/gobwas/glob

  • github.com/golang-jwt/jwt

  • github.com/golang/snappy

  • github.com/gomarkdown/markdown

  • github.com/google/uuid

  • github.com/goproxy/goproxy

  • github.com/gravwell/gcfg

  • github.com/gravwell/grokky

  • github.com/gravwell/ipfix

  • github.com/gravwell/srslog

  • github.com/h2non/filetype

  • github.com/howeyc/gopass

  • github.com/jaytaylor/html2text

  • github.com/klauspost/compress

  • github.com/klauspost/oui

  • github.com/lunixbochs/vtclean

  • github.com/lib/pq

  • github.com/manifoldco/promptui

  • github.com/mattn/go-colorable

  • github.com/minio/highwayhash

  • github.com/mmcloughlin/spherand

  • github.com/olekukonko/tablewriter

  • github.com/oschwald/maxminddb-golang AS maxminddb

  • github.com/phayes/freeport

  • github.com/pkg/errors

  • github.com/sijms/go-ora AS go_ora

  • github.com/smartystreets/assertions

  • github.com/spf13/viper

  • github.com/ssor/bom

  • github.com/tidwall/gjson

  • github.com/twmb/murmur3

  • github.com/vjeantet/grok

  • github.com/xi2/httpgzip