encapsulate sys.stdout.flush() into logger, guard against None sys.stdout (ESPTOOL-1008)

esptool/cmds.py

@@ -140,7 +140,7 @@ def check_if_stub(instance):
                     connect_mode, connect_attempts, detecting=True, warnings=False
                 )
             log.print("Detecting chip type...", end="")
-            sys.stdout.flush()
+            log.flush()
             chip_magic_value = detect_port.read_reg(
                 ESPLoader.CHIP_DETECT_MAGIC_REG_ADDR
             )
@@ -183,7 +183,7 @@ def load_ram(esp, args):
     for seg in image.segments:
         size = len(seg.data)
         log.print(f"Downloading {size} bytes at {seg.addr:08x}...", end=" ")
-        sys.stdout.flush()
+        log.flush()
         esp.mem_begin(
             size, div_roundup(size, esp.ESP_RAM_BLOCK), esp.ESP_RAM_BLOCK, seg.addr
         )
@@ -218,7 +218,7 @@ def dump_mem(esp, args):
                 percent = f.tell() * 100 // args.size
                 log.set_progress(percent)
                 log.print_overwrite(f"{f.tell()} bytes read... ({percent} %)")
-            sys.stdout.flush()
+            log.flush()
         log.print_overwrite(f"Read {f.tell()} bytes", last_line=True)
     log.print("Done!")
 
@@ -643,7 +643,7 @@ def write_flash(esp, args):
                         "Writing at 0x%08x... (%d %%)"
                         % (address + bytes_written, percent)
                     )
-                    sys.stdout.flush()
+                    log.flush()
                     block = image[0 : esp.FLASH_WRITE_SIZE]
                     if compress:
                         # feeding each compressed block into the decompressor lets us
@@ -697,7 +697,7 @@ def write_flash(esp, args):
                         break
                     except SerialException:
                         log.print(".", end="")
-                        sys.stdout.flush()
+                        log.flush()
                 else:
                     raise  # Reconnect limit reached
 

esptool/loader.py

@@ -629,7 +629,7 @@ def _connect_attempt(self, reset_strategy, mode="default_reset"):
                 return None
             except FatalError as e:
                 log.print(".", end="")
-                sys.stdout.flush()
+                log.flush()
                 time.sleep(0.05)
                 last_error = e
 
@@ -723,7 +723,7 @@ def connect(
             )
 
         log.print("Connecting...", end="")
-        sys.stdout.flush()
+        log.flush()
         last_error = None
 
         reset_sequence = self._construct_reset_strategy_sequence(mode)

esptool/logger.py

@@ -49,6 +49,12 @@ def set_progress(self, percentage: float):
         """
         pass
 
+    @abstractmethod
+    def flush():
+        """
+        Flushes the current loging to stdout
+        """
+        pass
 
 class EsptoolLogger(TemplateLogger):
     ansi_red = "\033[1;31m"
@@ -131,6 +137,14 @@ def set_progress(self, percentage: float):
         """
         pass
 
+    @abstractmethod
+    def flush():
+        try:
+            sys.stdout.flush()
+        except AttributeError:
+            # to handle certain contexts where sys.stdout is not available (None)
+            pass
+
     def set_logger(self, new_logger):
         self.__class__ = new_logger.__class__