admin: Add Background heal status info API (#7774)

This API returns the information related to the self healing routine.

For the moment, it returns:
- The total number of objects that are scanned
- The last time when an item was scanned

pkg/madmin/heal-commands.go

@@ -269,3 +269,37 @@ func (adm *AdminClient) Heal(bucket, prefix string, healOpts HealOpts,
 	}
 	return healStart, healTaskStatus, nil
 }
+
+// BgHealState represents the status of the background heal
+type BgHealState struct {
+	ScannedItemsCount int64
+	LastHealActivity  time.Time
+}
+
+// BackgroundHealStatus returns the background heal status of the
+// current server or cluster.
+func (adm *AdminClient) BackgroundHealStatus() (BgHealState, error) {
+	// Execute POST request to background heal status api
+	resp, err := adm.executeMethod("POST", requestData{relPath: "/v1/background-heal/status"})
+	if err != nil {
+		return BgHealState{}, err
+	}
+	defer closeResponse(resp)
+
+	if resp.StatusCode != http.StatusOK {
+		return BgHealState{}, httpRespToErrorResponse(resp)
+	}
+
+	respBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return BgHealState{}, err
+	}
+
+	var healState BgHealState
+
+	err = json.Unmarshal(respBytes, &healState)
+	if err != nil {
+		return BgHealState{}, err
+	}
+	return healState, nil
+}