[HADOOP-14385] HttpExceptionUtils#validateResponse swallows exceptions

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 3.3.0, 3.2.1, 3.1.3
• Assignee: Wei-Chiu Chuang
• Reporter: Wei-Chiu Chuang
• Created: 04/May/17 23:58
• Updated: 21/Jun/19 02:59
• Resolved: 21/Jun/19 02:59

Description

In the following code

HttpExceptionUtils#validateResponse

try {
        es = conn.getErrorStream();
        ObjectMapper mapper = new ObjectMapper();
        Map json = mapper.readValue(es, Map.class);
        json = (Map) json.get(ERROR_JSON);
        String exClass = (String) json.get(ERROR_CLASSNAME_JSON);
        String exMsg = (String) json.get(ERROR_MESSAGE_JSON);
        if (exClass != null) {
          try {
            ClassLoader cl = HttpExceptionUtils.class.getClassLoader();
            Class klass = cl.loadClass(exClass);
            Constructor constr = klass.getConstructor(String.class);
            toThrow = (Exception) constr.newInstance(exMsg);
          } catch (Exception ex) {
            toThrow = new IOException(String.format(
                "HTTP status [%d], exception [%s], message [%s] ",
                conn.getResponseCode(), exClass, exMsg));
          }
        } else {
          String msg = (exMsg != null) ? exMsg : conn.getResponseMessage();
          toThrow = new IOException(String.format(
              "HTTP status [%d], message [%s]", conn.getResponseCode(), msg));
        }
      } catch (Exception ex) {
        toThrow = new IOException(String.format( <-- here
            "HTTP status [%d], message [%s]", conn.getResponseCode(),
            conn.getResponseMessage()));
      }

If the an exception is thrown within the try block, the initial exception is swallowed, and it doesn't help debugging.
We had to cross reference this exception with the KMS server side to guess what happened.

IMHO the IOException thrown should also carry the initial exception. It should also print exClass and exMsg. It probably failed to instantiate an exception class.