commands: port tracing helper type from cephfs/admin

This debugging code can be made common.

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

internal/commands/trace.go

@@ -0,0 +1,51 @@
+package commands
+
+import (
+	"fmt"
+)
+
+// NewTraceCommander is a RadosCommander that wraps a given RadosCommander
+// and when commands are executes prints debug level "traces" to the
+// standard output.
+func NewTraceCommander(c RadosCommander) RadosCommander {
+	return &tracingCommander{c}
+}
+
+// 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 (t *tracingCommander) MgrCommand(buf [][]byte) ([]byte, string, error) {
+	fmt.Println("(MGR Command)")
+	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 (t *tracingCommander) MonCommand(buf []byte) ([]byte, string, error) {
+	fmt.Println("(MON Command)")
+	fmt.Println("IN:", string(buf))
+	r, s, err := t.conn.MonCommand(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
+}