target: Expose Target(max_async=50) parameter

Allow the user to set a maximum number of conrruent connections used to
dispatch non-blocking commands when using the async API.

devlib/target.py

@@ -306,9 +306,11 @@ def __init__(self,
                  load_default_modules=True,
                  shell_prompt=DEFAULT_SHELL_PROMPT,
                  conn_cls=None,
-                 is_container=False
+                 is_container=False,
+                 max_async=50,
                  ):
         self._async_pool = None
+        self._async_pool_size = None
         self._unused_conns = set()
 
         self._is_rooted = None
@@ -352,7 +354,7 @@ def __init__(self,
         self.modules = merge_lists(*module_lists, duplicates='first')
         self._update_modules('early')
         if connect:
-            self.connect()
+            self.connect(max_async=max_async)
 
     def __getstate__(self):
         # tls_property will recreate the underlying value automatically upon
@@ -363,12 +365,25 @@ def __getstate__(self):
             for k, v in inspect.getmembers(self.__class__)
             if isinstance(v, _BoundTLSProperty)
         }
+        ignored.update((
+            '_async_pool',
+            '_unused_conns',
+        ))
         return {
             k: v
             for k, v in self.__dict__.items()
             if k not in ignored
         }
 
+    def __setstate__(self, dct):
+        self.__dict__ = dct
+        pool_size = self._async_pool_size
+        if pool_size is None:
+            self._async_pool = None
+        else:
+            self._async_pool = ThreadPoolExecutor(pool_size)
+        self._unused_conns = set()
+
     # connection and initialization
 
     @asyn.asyncf
@@ -433,6 +448,7 @@ def make_conn(_):
         max_conns = len(conns)
 
         self.logger.debug(f'Detected max number of async commands: {max_conns}')
+        self._async_pool_size = max_conns
         self._async_pool = ThreadPoolExecutor(max_conns)
 
     @asyn.asyncf
@@ -1547,6 +1563,7 @@ def __init__(self,
                  shell_prompt=DEFAULT_SHELL_PROMPT,
                  conn_cls=SshConnection,
                  is_container=False,
+                 max_async=50,
                  ):
         super(LinuxTarget, self).__init__(connection_settings=connection_settings,
                                           platform=platform,
@@ -1557,7 +1574,8 @@ def __init__(self,
                                           load_default_modules=load_default_modules,
                                           shell_prompt=shell_prompt,
                                           conn_cls=conn_cls,
-                                          is_container=is_container)
+                                          is_container=is_container,
+                                          max_async=max_async)
 
     def wait_boot_complete(self, timeout=10):
         pass
@@ -1752,6 +1770,7 @@ def __init__(self,
                  conn_cls=AdbConnection,
                  package_data_directory="/data/data",
                  is_container=False,
+                 max_async=50,
                  ):
         super(AndroidTarget, self).__init__(connection_settings=connection_settings,
                                             platform=platform,
@@ -1762,7 +1781,8 @@ def __init__(self,
                                             load_default_modules=load_default_modules,
                                             shell_prompt=shell_prompt,
                                             conn_cls=conn_cls,
-                                            is_container=is_container)
+                                            is_container=is_container,
+                                            max_async=max_async)
         self.package_data_directory = package_data_directory
         self._init_logcat_lock()
 
@@ -2823,6 +2843,7 @@ def __init__(self,
                  shell_prompt=DEFAULT_SHELL_PROMPT,
                  conn_cls=LocalConnection,
                  is_container=False,
+                 max_async=50,
                  ):
         super(LocalLinuxTarget, self).__init__(connection_settings=connection_settings,
                                                platform=platform,
@@ -2833,7 +2854,8 @@ def __init__(self,
                                                load_default_modules=load_default_modules,
                                                shell_prompt=shell_prompt,
                                                conn_cls=conn_cls,
-                                               is_container=is_container)
+                                               is_container=is_container,
+                                               max_async=max_async)
 
     def _resolve_paths(self):
         if self.working_directory is None:
@@ -2906,7 +2928,8 @@ def __init__(self,
                  load_default_modules=True,
                  shell_prompt=DEFAULT_SHELL_PROMPT,
                  package_data_directory="/data/data",
-                 is_container=False
+                 is_container=False,
+                 max_async=50,
                  ):
 
         self.supports_android = None
@@ -2932,7 +2955,8 @@ def __init__(self,
                                              load_default_modules=load_default_modules,
                                              shell_prompt=shell_prompt,
                                              conn_cls=SshConnection,
-                                             is_container=is_container)
+                                             is_container=is_container,
+                                             max_async=max_async)
 
         # We can't determine if the target supports android until connected to the linux host so
         # create unconditionally.

doc/target.rst

@@ -3,7 +3,7 @@
 Target
 ======
 
-.. class:: Target(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=None)
+.. class:: Target(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=None, max_async=50)
 
     :class:`~devlib.target.Target` is the primary interface to the remote
     device. All interactions with the device are performed via a
@@ -76,6 +76,9 @@ Target
     :param conn_cls: This is the type of connection that will be used to
         communicate with the device.
 
+    :param max_async: Maximum number of opened connections to the target used to
+                      issue non-blocking commands when using the async API.
+
 .. attribute:: Target.core_names
 
    This is a list containing names of CPU cores on the target, in the order in
@@ -606,7 +609,7 @@ Target
 Linux Target
 ------------
 
-.. class:: LinuxTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=SshConnection, is_container=False,)
+.. class:: LinuxTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=SshConnection, is_container=False, max_async=50)
 
     :class:`LinuxTarget` is a subclass of :class:`~devlib.target.Target`
     with customisations specific to a device running linux.
@@ -615,7 +618,7 @@ Linux Target
 Local Linux Target
 ------------------
 
-.. class:: LocalLinuxTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=SshConnection, is_container=False,)
+.. class:: LocalLinuxTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=SshConnection, is_container=False, max_async=50)
 
     :class:`LocalLinuxTarget` is a subclass of
     :class:`~devlib.target.LinuxTarget` with customisations specific to using
@@ -625,7 +628,7 @@ Local Linux Target
 Android Target
 ---------------
 
-.. class:: AndroidTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=AdbConnection, package_data_directory="/data/data")
+.. class:: AndroidTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, conn_cls=AdbConnection, package_data_directory="/data/data", max_async=50)
 
     :class:`AndroidTarget` is a subclass of :class:`~devlib.target.Target` with
     additional features specific to a device running Android.
@@ -773,7 +776,7 @@ Android Target
 ChromeOS Target
 ---------------
 
-.. class:: ChromeOsTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, android_working_directory=None, android_executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, package_data_directory="/data/data")
+.. class:: ChromeOsTarget(connection_settings=None, platform=None, working_directory=None, executables_directory=None, android_working_directory=None, android_executables_directory=None, connect=True, modules=None, load_default_modules=True, shell_prompt=DEFAULT_SHELL_PROMPT, package_data_directory="/data/data", max_async=50)
 
     :class:`ChromeOsTarget` is a subclass of :class:`LinuxTarget` with
     additional features specific to a device running ChromeOS for example,