[FAB-3431] Always display error callstack in logs

This CR removes the dependency on core.yaml for setting the display
of the callstack, resulting in all calls to Error() appending the
callstack (if available). This ensures the logs will always contain
the callstack. It also modifies the Message() function to only display
the error message (without callstack) for cases where just the message
message is desired. Finally, it refactors the unit tests to avoid the
previously large amount of duplicated code between test cases.

Change-Id: I379a3258fd2b357f2b5504896ff8f2ad4d5e7788
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>

Author: wlahti

common/errors/errors.go

@@ -23,7 +23,6 @@ import (
 	"regexp"
 	"runtime"
 
-	"github.com/hyperledger/fabric/common/flogging"
 	logging "github.com/op/go-logging"
 )
 
@@ -73,9 +72,18 @@ func setupCallError(e *callError, generateStack bool) {
 	e.stack = stack[:length]
 }
 
-// Error comes from the error interface
+// Error comes from the error interface - it returns the error message and
+// appends the callstack, if available
 func (e *callError) Error() string {
-	return e.Message()
+	message := e.GetErrorCode() + " - " + fmt.Sprintf(e.message, e.args...)
+	// check that the error has a callstack before proceeding
+	if e.GetStack() != "" {
+		message = appendCallStack(message, e.GetStack())
+	}
+	if e.prevErr != nil {
+		message += "\nCaused by: " + e.prevErr.Error()
+	}
+	return message
 }
 
 // GetStack returns the call stack as a string
@@ -102,18 +110,14 @@ func (e *callError) GetErrorCode() string {
 // language.
 func (e *callError) Message() string {
 	message := e.GetErrorCode() + " - " + fmt.Sprintf(e.message, e.args...)
-	// check that the error has a callstack before proceeding
-	if e.GetStack() != "" {
-		// stacktrace is enabled when `logging.error` in core.yaml is set to
-		// DEBUG. it can also be toggled for code running on the peer dynamically
-		// via CLI using `peer logging setlevel error <log-level>`
-		errorLevel := flogging.GetModuleLevel("error")
-		if errorLevel == logging.DEBUG.String() {
-			message = appendCallStack(message, e.GetStack())
-		}
-	}
+
 	if e.prevErr != nil {
-		message += "\nCaused by: " + e.prevErr.Error()
+		switch previousError := e.prevErr.(type) {
+		case CallStackError:
+			message += "\nCaused by: " + previousError.Message()
+		default:
+			message += "\nCaused by: " + e.prevErr.Error()
+		}
 	}
 	return message
 }