bitbake: asyncrpc: Add context manager API

Adds context manager API for the asyncrcp client class which allow
writing code that will automatically close the connection like so:

    with hashserv.create_client(address) as client:
       ...

Rework the bitbake-hashclient tool and PR server to use this new API to
fix warnings about unclosed event loops when exiting

(Bitbake rev: 52226a7244968c8dad6f4ee9ccec57ac1979217a)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit d01d684a0f6398270fe35ed59b7d28f3fd9b7e41)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

bitbake/bin/bitbake-hashclient

@@ -56,25 +56,24 @@ def main():
             nonlocal missed_hashes
             nonlocal max_time
 
-            client = hashserv.create_client(args.address)
+            with hashserv.create_client(args.address) as client:
+                for i in range(args.requests):
+                    taskhash = hashlib.sha256()
+                    taskhash.update(args.taskhash_seed.encode('utf-8'))
+                    taskhash.update(str(i).encode('utf-8'))
 
-            for i in range(args.requests):
-                taskhash = hashlib.sha256()
-                taskhash.update(args.taskhash_seed.encode('utf-8'))
-                taskhash.update(str(i).encode('utf-8'))
+                    start_time = time.perf_counter()
+                    l = client.get_unihash(METHOD, taskhash.hexdigest())
+                    elapsed = time.perf_counter() - start_time
 
-                start_time = time.perf_counter()
-                l = client.get_unihash(METHOD, taskhash.hexdigest())
-                elapsed = time.perf_counter() - start_time
+                    with lock:
+                        if l:
+                            found_hashes += 1
+                        else:
+                            missed_hashes += 1
 
-                with lock:
-                    if l:
-                        found_hashes += 1
-                    else:
-                        missed_hashes += 1
-
-                    max_time = max(elapsed, max_time)
-                    pbar.update()
+                        max_time = max(elapsed, max_time)
+                        pbar.update()
 
         max_time = 0
         found_hashes = 0
@@ -174,9 +173,8 @@ def main():
 
     func = getattr(args, 'func', None)
     if func:
-        client = hashserv.create_client(args.address)
-
-        return func(args, client)
+        with hashserv.create_client(args.address) as client:
+            return func(args, client)
 
     return 0
 

bitbake/lib/bb/asyncrpc/client.py

@@ -126,6 +126,12 @@ class AsyncClient(object):
             {'ping': {}}
         )
 
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc_value, traceback):
+        await self.close()
+
 
 class Client(object):
     def __init__(self):
@@ -176,3 +182,10 @@ class Client(object):
         if sys.version_info >= (3, 6):
             self.loop.run_until_complete(self.loop.shutdown_asyncgens())
         self.loop.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.close()
+        return False

bitbake/lib/prserv/serv.py

@@ -344,9 +344,9 @@ def auto_shutdown():
 def ping(host, port):
     from . import client
 
-    conn = client.PRClient()
-    conn.connect_tcp(host, port)
-    return conn.ping()
+    with client.PRClient() as conn:
+        conn.connect_tcp(host, port)
+        return conn.ping()
 
 def connect(host, port):
     from . import client