Documentation
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Overview ¶
Package execnode provides the Exec node implementation (Node-RED type ID "exec" - named execnode here to avoid shadowing the imported stdlib os/exec package within this file).
Security ¶
This node runs an external command with the same OS privileges as the Go-RED process. Anyone able to deploy a flow that uses it can therefore run arbitrary commands on the host - this is inherent to the feature (Node-RED's own exec node has the identical property) and cannot be fully engineered away, only its sharpest edges blunted:
- Command is fixed at deploy time via node configuration and is never read from the message; a compromised or malicious upstream node in the same flow cannot redirect execution to a different binary.
- Arguments are always passed as a Go argv slice via exec.CommandContext(ctx, Command, args...), never through a shell (no "sh -c", unlike Node-RED's default useSpawn=false mode). Nothing in Args or in msg.payload (if AppendPayload is set) is ever interpreted for shell metacharacters (;, |, $(), backticks, ...), because there is no shell in the path at all.
- Every run is bounded by TimeoutMs and by a fixed cap on captured stdout/stderr bytes, so a runaway or wedged command can't hang a node indefinitely or exhaust memory.
- The node refuses to run at all unless the enableEnvVar environment variable is set on the Go-RED process - an explicit, instance-level opt-in, not just something gated by editor/API auth. A fresh Go-RED deployment cannot execute commands by accident.
Index ¶
Constants ¶
This section is empty.
Variables ¶
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Functions ¶
This section is empty.
Types ¶
type Node ¶
type Node struct {
// Command is the executable name or path. Fixed at deploy time - never
// taken from the message. Required.
Command string
// Args are fixed extra arguments, in order, before any AppendPayload
// arguments.
Args []string
// AppendPayload, if true, appends msg.payload - which must be a string
// or an array of strings - as trailing argv entries.
AppendPayload bool
// TimeoutMs bounds how long the command may run.
TimeoutMs int64
}
Node holds an Exec node's configuration.
func (*Node) Execute ¶
func (n *Node) Execute(ctx interface{}, input map[string]interface{}) (map[string]interface{}, error)
Execute runs Command with Args (+ msg.payload if AppendPayload), and returns a copy of input with payload set to captured stdout, "stderr" set to captured stderr, and "exitCode" set to the process's exit code.
Source Files