add processor to execute commands on system

internal/processor/os-exec.go

@@ -0,0 +1,124 @@
+package processor
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"text/template"
+
+	"github.com/google/jsonschema-go/jsonschema"
+	"github.com/jwetzell/showbridge-go/config"
+	"github.com/jwetzell/showbridge-go/internal/common"
+)
+
+func init() {
+	RegisterProcessor(ProcessorRegistration{
+		Type:  "os.exec",
+		Title: "Exec Command",
+		ParamsSchema: &jsonschema.Schema{
+			Type: "object",
+			Properties: map[string]*jsonschema.Schema{
+				"command": {
+					Title:       "Command",
+					Description: "the command to execute",
+					Type:        "string",
+				},
+				"args": {
+					Title:       "Args",
+					Description: "the arguments for the command",
+					Type:        "array",
+					Items: &jsonschema.Schema{
+						Type: "string",
+					},
+				},
+			},
+			AdditionalProperties: &jsonschema.Schema{Not: &jsonschema.Schema{}},
+			Required:             []string{"command"},
+		},
+		New: func(moduleConfig config.ProcessorConfig) (Processor, error) {
+			params := moduleConfig.Params
+
+			commandString, err := params.GetString("command")
+			if err != nil {
+				if errors.Is(err, config.ErrParamNotFound) {
+					return nil, fmt.Errorf("os.exec command error: not found")
+				} else {
+					return nil, fmt.Errorf("os.exec command error: %w", err)
+				}
+			}
+			commandTemplate, err := template.New("command").Parse(commandString)
+
+			if err != nil {
+				return nil, err
+			}
+
+			argStrings, err := params.GetStringSlice("args")
+			if err != nil {
+				if errors.Is(err, config.ErrParamNotFound) {
+					argStrings = []string{}
+				} else {
+					return nil, fmt.Errorf("os.exec args error: %w", err)
+				}
+			}
+
+			argTemplates := make([]*template.Template, len(argStrings))
+			for i, argString := range argStrings {
+				argTemplate, err := template.New(fmt.Sprintf("arg-%d", i)).Parse(argString)
+				if err != nil {
+					return nil, err
+				}
+				argTemplates[i] = argTemplate
+			}
+			return &OsExec{config: moduleConfig, CommandTemplate: commandTemplate, Args: argTemplates}, nil
+		},
+	})
+}
+
+type OsExec struct {
+	CommandTemplate *template.Template
+	config          config.ProcessorConfig
+	Args            []*template.Template
+}
+
+func (oe *OsExec) Process(ctx context.Context, wrappedPayload common.WrappedPayload) (common.WrappedPayload, error) {
+	templateData := wrappedPayload
+
+	var commandBuffer bytes.Buffer
+	err := oe.CommandTemplate.Execute(&commandBuffer, templateData)
+
+	if err != nil {
+		wrappedPayload.End = true
+		return wrappedPayload, err
+	}
+
+	commandString := commandBuffer.String()
+
+	argStrings := make([]string, len(oe.Args))
+	for i, argTemplate := range oe.Args {
+		var argBuffer bytes.Buffer
+		err := argTemplate.Execute(&argBuffer, templateData)
+		if err != nil {
+			wrappedPayload.End = true
+			return wrappedPayload, err
+		}
+		argStrings[i] = argBuffer.String()
+	}
+
+	out, err := exec.Command(commandString, argStrings...).Output()
+	if err != nil {
+		wrappedPayload.End = true
+		return wrappedPayload, fmt.Errorf("os.exec command execution error: %w", err)
+	}
+	wrappedPayload.Payload = out
+	return wrappedPayload, nil
+}
+
+func (oe *OsExec) Id() string {
+	return oe.config.Id
+}
+
+func (oe *OsExec) Type() string {
+	return oe.config.Type
+}