cephfs admin: add optional debug tracing to the tests

Allow the environment variable GO_CEPH_TEST_DEBUG_TRACE=yes to enable
tracing of the input & output json from the manager commands. This is
both useful for debugging the tests themselves and demonstrates the use
of something other than rados.Conn meeting the interface required by
FSAdmin.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

cephfs/admin/fsadmin_test.go

@@ -2,22 +2,66 @@ package admin
 
 import (
 	"errors"
+	"fmt"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-var cachedFSAdmin *FSAdmin
+var (
+	cachedFSAdmin *FSAdmin
+
+	// set debugTrace to true to use tracing in tests
+	debugTrace = false
+)
+
+func init() {
+	dt := os.Getenv("GO_CEPH_TEST_DEBUG_TRACE")
+	if dt == "yes" || dt == "true" {
+		debugTrace = true
+	}
+}
+
+// tracingCommander serves two purposes: first, it allows one to trace the
+// input and output json when running the tests. It can help with actually
+// debugging the tests. Second, it demonstrates the rationale for using an
+// interface in FSAdmin. You can layer any sort of debugging, error injection,
+// or whatnot between the FSAdmin layer and the RADOS layer.
+type tracingCommander struct {
+	conn RadosCommander
+}
+
+func tracer(c RadosCommander) RadosCommander {
+	return &tracingCommander{c}
+}
+
+func (t *tracingCommander) MgrCommand(buf [][]byte) ([]byte, string, error) {
+	for i := range buf {
+		fmt.Println("IN:", string(buf[i]))
+	}
+	r, s, err := t.conn.MgrCommand(buf)
+	fmt.Println("OUT(result):", string(r))
+	if s != "" {
+		fmt.Println("OUT(status):", s)
+	}
+	if err != nil {
+		fmt.Println("OUT(error):", err.Error())
+	}
+	return r, s, err
+}
 
 func getFSAdmin(t *testing.T) *FSAdmin {
 	if cachedFSAdmin != nil {
 		return cachedFSAdmin
 	}
-	var err error
 	cachedFSAdmin, err := New()
 	require.NoError(t, err)
 	require.NotNil(t, cachedFSAdmin)
+	if debugTrace {
+		cachedFSAdmin = NewFromConn(tracer(cachedFSAdmin.conn))
+	}
 	return cachedFSAdmin
 }