Update runc kill wrapper to take a string for signal

Signed-off-by: Kathryn Baldauf <kabaldau@microsoft.com>

runc.go

@@ -327,6 +327,7 @@ func (r *Runc) Delete(context context.Context, id string, opts *DeleteOpts) erro
 type KillOpts struct {
 	All       bool
 	ExtraArgs []string
+	RawSignal string
 }
 
 func (o *KillOpts) args() (out []string) {
@@ -344,10 +345,14 @@ func (r *Runc) Kill(context context.Context, id string, sig int, opts *KillOpts)
 	args := []string{
 		"kill",
 	}
+	killSignal := strconv.Itoa(sig)
 	if opts != nil {
 		args = append(args, opts.args()...)
+		if opts.RawSignal != "" {
+			killSignal = opts.RawSignal
+		}
 	}
-	return r.runOrError(r.command(context, append(args, id, strconv.Itoa(sig))...))
+	return r.runOrError(r.command(context, append(args, id, killSignal)...))
 }
 
 // Stats return the stats for a container like cpu, memory, and io

runc_test.go

@@ -21,6 +21,7 @@ import (
 	"errors"
 	"io/ioutil"
 	"os"
+	"strings"
 	"sync"
 	"syscall"
 	"testing"
@@ -287,9 +288,7 @@ func interrupt(ctx context.Context, t *testing.T, started <-chan int) {
 	}
 }
 
-// dummySleepRunc creates s simple script that just runs `sleep 10` to replace
-// runc for testing process that are longer running.
-func dummySleepRunc() (_ string, err error) {
+func createScript(content string) (_ string, err error) {
 	fh, err := ioutil.TempFile("", "*.sh")
 	if err != nil {
 		return "", err
@@ -299,7 +298,7 @@ func dummySleepRunc() (_ string, err error) {
 			os.Remove(fh.Name())
 		}
 	}()
-	_, err = fh.Write([]byte("#!/bin/sh\nexec /bin/sleep 10"))
+	_, err = fh.Write([]byte(content))
 	if err != nil {
 		return "", err
 	}
@@ -314,6 +313,22 @@ func dummySleepRunc() (_ string, err error) {
 	return fh.Name(), nil
 }
 
+// dummySleepRunc creates a simple script that just runs `sleep 10` to replace
+// runc for testing process that are longer running.
+func dummySleepRunc() (_ string, err error) {
+	return createScript("#!/bin/sh\nexec /bin/sleep 10")
+}
+
+// debugCommand creates a simple script that echos the arguments passed to
+// runc, and returns them as part of the error message.
+func debugCommand() (string, error) {
+	return createScript(`#!/bin/sh
+	echo "$@"
+	# force non-zero exit code, so that the error message contains the output
+	exit 1
+	`)
+}
+
 func TestCreateArgs(t *testing.T) {
 	o := &CreateOpts{}
 	args, err := o.args()
@@ -336,3 +351,72 @@ func TestCreateArgs(t *testing.T) {
 	}
 
 }
+
+func TestRuncKill(t *testing.T) {
+	ctx, timeout := context.WithTimeout(context.Background(), 10*time.Second)
+	defer timeout()
+
+	dummyCmd, err := debugCommand()
+	if err != nil {
+		t.Fatalf("Failed to create dummy debug command: %v", err)
+	}
+	defer os.Remove(dummyCmd)
+
+	debugRunc := &Runc{Command: dummyCmd}
+
+	type config struct {
+		name            string
+		rawSignal       string
+		numericalSignal int
+		expectedSignal  string
+	}
+	tests := []config{
+		{
+			name:           "Kill sends raw signal",
+			rawSignal:      "SIGTERM",
+			expectedSignal: "SIGTERM",
+		},
+		{
+			name:           "Kill sends raw signal number",
+			rawSignal:      "15",
+			expectedSignal: "15",
+		},
+		{
+			name:            "Kill prefers raw signal over numerical signal",
+			rawSignal:       "SIGTERM",
+			numericalSignal: 9,
+			expectedSignal:  "SIGTERM",
+		},
+		{
+			name:            "Kill prefers raw signal number over numerical signal",
+			rawSignal:       "15",
+			numericalSignal: 9,
+			expectedSignal:  "15",
+		},
+		{
+			name:            "Kill sends numerical signal when no raw signal specified",
+			numericalSignal: 9,
+			expectedSignal:  "9",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(_ *testing.T) {
+			opts := &KillOpts{
+				RawSignal: test.rawSignal,
+			}
+			err = debugRunc.Kill(ctx, "fake_id", test.numericalSignal, opts)
+			if err == nil {
+				t.Fatal("expected dummy debug command to return error, instead got nil")
+			}
+			errorMessage := err.Error()
+			words := strings.Fields(errorMessage)
+			if len(words) < 3 {
+				t.Fatalf("expected dummy debug command to error with the kill command sent, instead got %s", errorMessage)
+			}
+			actualSignal := words[len(words)-1]
+			if actualSignal != test.expectedSignal {
+				t.Fatalf("expected kill command to send signal %v, instead got %v", test.expectedSignal, actualSignal)
+			}
+		})
+	}
+}