libpod: Execute poststop hooks locally

Instead of delegating to the runtime, since some runtimes do not seem
to handle these reliably [1].

[1]: https://github.com/projectatomic/libpod/issues/730#issuecomment-392959938

Signed-off-by: W. Trevor King <wking@tremily.us>

Closes: #864
Approved by: rhatdan

libpod/container_internal_test.go

@@ -0,0 +1,80 @@
+package libpod
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	rspec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/stretchr/testify/assert"
+)
+
+// hookPath is the path to an example hook executable.
+var hookPath string
+
+func TestPostDeleteHooks(t *testing.T) {
+	ctx := context.Background()
+	dir, err := ioutil.TempDir("", "libpod_test_")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	statePath := filepath.Join(dir, "state")
+	copyPath := filepath.Join(dir, "copy")
+	c := Container{
+		config: &ContainerConfig{
+			ID: "123abc",
+			Spec: &rspec.Spec{
+				Annotations: map[string]string{
+					"a": "b",
+				},
+			},
+			StaticDir: dir, // not the bundle, but good enough for this test
+		},
+		state: &containerState{
+			ExtensionStageHooks: map[string][]rspec.Hook{
+				"poststop": {
+					rspec.Hook{
+						Path: hookPath,
+						Args: []string{"sh", "-c", fmt.Sprintf("cat >%s", statePath)},
+					},
+					rspec.Hook{
+						Path: "/does/not/exist",
+					},
+					rspec.Hook{
+						Path: hookPath,
+						Args: []string{"sh", "-c", fmt.Sprintf("cp %s %s", statePath, copyPath)},
+					},
+				},
+			},
+		},
+	}
+	err = c.postDeleteHooks(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stateRegexp := "{\"ociVersion\":\"1\\.0\\.0\",\"id\":\"123abc\",\"status\":\"stopped\",\"bundle\":\"/tmp/libpod_test_[0-9]*\",\"annotations\":{\"a\":\"b\"}}"
+	for _, path := range []string{statePath, copyPath} {
+		t.Run(path, func(t *testing.T) {
+			content, err := ioutil.ReadFile(path)
+			if err != nil {
+				t.Fatal(err)
+			}
+			assert.Regexp(t, stateRegexp, string(content))
+		})
+	}
+}
+
+func init() {
+	if runtime.GOOS != "windows" {
+		hookPath = "/bin/sh"
+	} else {
+		panic("we need a reliable executable path on Windows")
+	}
+}