Merge pull request #243 from jwetzell/feat/os-exec

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
+}

internal/processor/test/os-exec_test.go

@@ -0,0 +1,170 @@
+package processor_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/jwetzell/showbridge-go/config"
+	"github.com/jwetzell/showbridge-go/internal/common"
+	"github.com/jwetzell/showbridge-go/internal/processor"
+	"github.com/jwetzell/showbridge-go/internal/test"
+)
+
+func TestOsExecFromRegistry(t *testing.T) {
+	registration, ok := processor.GetProcessorRegistration("os.exec")
+	if !ok {
+		t.Fatalf("os.exec processor not registered")
+	}
+
+	processorInstance, err := registration.New(config.ProcessorConfig{
+		Id:   "test-id",
+		Type: "os.exec",
+		Params: map[string]any{
+			"command": "ls",
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to create os.exec processor: %s", err)
+	}
+
+	if processorInstance.Id() != "test-id" {
+		t.Fatalf("os.exec processor has wrong id: %s", processorInstance.Id())
+	}
+
+	if processorInstance.Type() != "os.exec" {
+		t.Fatalf("os.exec processor has wrong type: %s", processorInstance.Type())
+	}
+}
+
+func TestGoodOsExec(t *testing.T) {
+	testCases := []struct {
+		name     string
+		params   map[string]any
+		payload  any
+		expected []byte
+	}{}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			registration, ok := processor.GetProcessorRegistration("os.exec")
+			if !ok {
+				t.Fatalf("os.exec processor not registered")
+			}
+
+			processorInstance, err := registration.New(config.ProcessorConfig{
+				Type:   "os.exec",
+				Params: testCase.params,
+			})
+
+			if err != nil {
+				t.Fatalf("os.exec failed to create processor: %s", err)
+			}
+
+			got, err := processorInstance.Process(t.Context(), common.WrappedPayload{Payload: testCase.payload})
+
+			if err != nil {
+				t.Fatalf("os.exec processing failed: %s", err)
+			}
+
+			if !reflect.DeepEqual(got.Payload, testCase.expected) {
+				t.Fatalf("os.exec got payload '%v', expected '%v'", got.Payload, testCase.expected)
+			}
+		})
+	}
+}
+
+func TestBadOsExec(t *testing.T) {
+	tests := []struct {
+		name        string
+		params      map[string]any
+		payload     any
+		errorString string
+	}{
+		{
+			name:        "no command parameter",
+			params:      map[string]any{},
+			payload:     test.TestStruct{},
+			errorString: "os.exec command error: not found",
+		},
+		{
+			name: "non-string command parameter",
+			params: map[string]any{
+				"command": 12345,
+			},
+			payload:     test.TestStruct{},
+			errorString: "os.exec command error: not a string",
+		},
+		{
+			name: "command template syntax error",
+			params: map[string]any{
+				"command": "{{",
+			},
+			payload:     test.TestStruct{},
+			errorString: "template: command:1: unclosed action",
+		},
+		{
+			name: "command templating error",
+			params: map[string]any{
+				"command": "{{.NonExistentField}}",
+			},
+			payload:     test.TestStruct{},
+			errorString: "template: command:1:2: executing \"command\" at <.NonExistentField>: can't evaluate field NonExistentField in type common.WrappedPayload",
+		},
+		{
+			name: "non-string in args",
+			params: map[string]any{
+				"command": "echo",
+				"args":    []any{12345},
+			},
+			payload:     test.TestStruct{},
+			errorString: "os.exec args error: not a string slice",
+		},
+		{
+			name: "args template syntax error",
+			params: map[string]any{
+				"command": "echo",
+				"args":    []any{"{{"},
+			},
+			payload:     test.TestStruct{},
+			errorString: "template: arg-0:1: unclosed action",
+		},
+		{
+			name: "args templating error",
+			params: map[string]any{
+				"command": "echo",
+				"args":    []any{"{{.Unknown}}"},
+			},
+			payload:     test.TestStruct{},
+			errorString: "template: arg-0:1:2: executing \"arg-0\" at <.Unknown>: can't evaluate field Unknown in type common.WrappedPayload",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			registration, ok := processor.GetProcessorRegistration("os.exec")
+			if !ok {
+				t.Fatalf("os.exec processor not registered")
+			}
+
+			processorInstance, err := registration.New(config.ProcessorConfig{
+				Type:   "os.exec",
+				Params: test.params,
+			})
+			if err != nil {
+				if err.Error() != test.errorString {
+					t.Fatalf("os.exec got error '%s', expected '%s'", err.Error(), test.errorString)
+				}
+				return
+			}
+			got, err := processorInstance.Process(t.Context(), common.WrappedPayload{Payload: test.payload})
+
+			if err == nil {
+				t.Fatalf("os.exec expected to fail but succeeded, got: %v", got)
+
+			}
+			if err.Error() != test.errorString {
+				t.Fatalf("os.exec got error '%s', expected '%s'", err.Error(), test.errorString)
+			}
+		})
+	}
+}