feat: Better formatted output for detected events. (#573)

* feat: Better formatted output for detected events.

Signed-off-by: Simarpreet Singh <simar@linux.com>

* fix: Format time as UTC in RFC3339

Signed-off-by: Simarpreet Singh <simar@linux.com>

* fix: Add a testcase for unsupport input event

Signed-off-by: Simarpreet Singh <simar@linux.com>

* feat: Include signature ID in detection output

Signed-off-by: Simarpreet Singh <simar@linux.com>

* feat: Rework fields for display

Signed-off-by: Simarpreet Singh <simar@linux.com>

tracee-rules/main.go

@@ -7,11 +7,23 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"github.com/aquasecurity/tracee/tracee-rules/engine"
 	"github.com/urfave/cli/v2"
 )
 
+type Clock interface {
+	Now() time.Time
+}
+
+type realClock struct {
+}
+
+func (realClock) Now() time.Time {
+	return time.Now()
+}
+
 func main() {
 	app := &cli.App{
 		Name:  "tracee-rules",
@@ -56,7 +68,7 @@ func main() {
 			if inputs == (engine.EventSources{}) {
 				return err
 			}
-			output, err := setupOutput(c.String("webhook"))
+			output, err := setupOutput(os.Stdout, realClock{}, c.String("webhook"))
 			if err != nil {
 				return err
 			}

tracee-rules/output.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"strings"
@@ -12,11 +13,36 @@ import (
 	"github.com/aquasecurity/tracee/tracee-rules/types"
 )
 
-func setupOutput(webhook string) (chan types.Finding, error) {
+const DetectionOutput string = `
+*** Detection ***
+Time: %s
+Signature ID: %s
+Signature: %s
+Data: %s
+Command: %s
+Hostname: %s
+`
+
+func setupOutput(resultWriter io.Writer, clock Clock, webhook string) (chan types.Finding, error) {
 	out := make(chan types.Finding)
 	go func() {
 		for res := range out {
-			fmt.Printf("%+v\n", res)
+			sigMetadata, err := res.Signature.GetMetadata()
+			if err != nil {
+				log.Println("invalid signature metadata: ", err)
+				continue
+			}
+
+			switch res.Context.(type) {
+			case tracee.Event:
+				command := res.Context.(tracee.Event).ProcessName
+				hostName := res.Context.(tracee.Event).HostName
+				fmt.Fprintf(resultWriter, DetectionOutput, clock.Now().UTC().Format(time.RFC3339), sigMetadata.ID, sigMetadata.Name, res.Data, command, hostName)
+			default:
+				log.Printf("unsupported event detected: %T\n", res.Context)
+				continue
+			}
+
 			if webhook != "" {
 				payload, err := prepareJSONPayload(res)
 				if err != nil {

tracee-rules/output_test.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	"github.com/aquasecurity/tracee/tracee-ebpf/tracee/external"
+
+	"github.com/aquasecurity/tracee/tracee-rules/types"
+	"github.com/stretchr/testify/assert"
+
+	"github.com/stretchr/testify/require"
+)
+
+type fakeClock struct {
+}
+
+func (fakeClock) Now() time.Time {
+	return time.Unix(1614045297, 0)
+}
+
+type fakeSignature struct {
+	types.Signature
+}
+
+func (f fakeSignature) GetMetadata() (types.SignatureMetadata, error) {
+	return types.SignatureMetadata{
+		ID:          "FOO-666",
+		Name:        "foo bar signature",
+		Description: "the most evil",
+	}, nil
+}
+
+func Test_setupOutput(t *testing.T) {
+	var testCases = []struct {
+		name           string
+		inputContext   interface{}
+		expectedOutput string
+	}{
+		{
+			name: "happy path with tracee event",
+			inputContext: external.Event{
+				Timestamp:   12345678,
+				ProcessName: "foobar.exe",
+				HostName:    "foobar.local",
+			},
+			expectedOutput: `
+*** Detection ***
+Time: 2021-02-23T01:54:57Z
+Signature ID: FOO-666
+Signature: foo bar signature
+Data: map[foo1:bar1, baz1 foo2:[bar2 baz2]]
+Command: foobar.exe
+Hostname: foobar.local
+`,
+		},
+		{
+			name: "sad path with unknown context",
+			inputContext: struct {
+				foo string
+			}{foo: "bad input context"},
+			expectedOutput: ``,
+		},
+	}
+
+	for _, tc := range testCases {
+		var actualOutput bytes.Buffer
+		findingCh, err := setupOutput(&actualOutput, fakeClock{}, "")
+		require.NoError(t, err, tc.name)
+
+		findingCh <- types.Finding{
+			Data: map[string]interface{}{
+				"foo1": "bar1, baz1",
+				"foo2": []string{"bar2", "baz2"},
+			},
+			Context:   tc.inputContext,
+			Signature: fakeSignature{},
+		}
+
+		time.Sleep(time.Millisecond)
+		assert.Equal(t, tc.expectedOutput, actualOutput.String(), tc.name)
+	}
+}