Add expect feature

shlax/subprocess.py

@@ -7,10 +7,10 @@ import sys
 from .colors import colors
 
 
-class SubprocessProtocol(asyncio.SubprocessProtocol):
-    def __init__(self, proc):
+class SubprocessProtocol(asyncio.subprocess.SubprocessStreamProtocol):
+    def __init__(self, proc, *args, **kwargs):
         self.proc = proc
-        self.output = bytearray()
+        super().__init__(*args, **kwargs)
 
     def pipe_data_received(self, fd, data):
         if fd == 1:
@@ -18,8 +18,12 @@ class SubprocessProtocol(asyncio.SubprocessProtocol):
         elif fd == 2:
             self.proc.stderr(data)
 
-    def process_exited(self):
-        self.proc.exit_future.set_result(True)
+        if self.proc.expect_index < len(self.proc.expects):
+            expected = self.proc.expects[self.proc.expect_index]
+            if re.match(expected['regexp'], data):
+                self.stdin.write(expected['sendline'])
+                self.stdin.flush()
+                self.proc.expect_index += 1
 
 
 class Subprocess:
@@ -45,18 +49,21 @@ class Subprocess:
 
     def __init__(
         self,
-        *args,
+        cmd,
         quiet=None,
         prefix=None,
         regexps=None,
+        expects=None,
         write=None,
         flush=None,
     ):
-        self.args = args
+        self.cmd = cmd
         self.quiet = quiet if quiet is not None else False
         self.prefix = prefix
         self.write = write or sys.stdout.buffer.write
         self.flush = flush or sys.stdout.flush
+        self.expects = expects or []
+        self.expect_index = 0
         self.started = False
         self.waited = False
         self.out_raw = bytearray()
@@ -76,32 +83,27 @@ class Subprocess:
             self.output(
                 self.colors.bgray.encode()
                 + b'+ '
-                + ' '.join([
-                    arg.replace('\n', '\\n')
-                    for arg in self.args
-                ]).encode()
+                + self.cmd.encode()
                 + self.colors.reset.encode(),
                 highlight=False
             )
 
-        # Get a reference to the event loop as we plan to use
-        # low-level APIs.
+        # The following is a copy of what asyncio.create_subprocess_shell does
+        # except we inject our own SubprocessStreamProtocol subclass: it might
+        # need an update as new python releases come out.
         loop = asyncio.get_running_loop()
-
-        self.exit_future = asyncio.Future(loop=loop)
-
-        if len(self.args) == 1 and ' ' in self.args[0]:
-            args = ['sh', '-euc', self.args[0]]
-        else:
-            args = self.args
-
-        # Create the subprocess controlled by DateProtocol;
-        # redirect the standard output into a pipe.
-        self.transport, self.protocol = await loop.subprocess_exec(
-            lambda: SubprocessProtocol(self),
-            *args,
-            stdin=None,
+        self.transport, self.protocol = await loop.subprocess_shell(
+            lambda: SubprocessProtocol(
+                self,
+                limit=asyncio.subprocess.streams._DEFAULT_LIMIT,
+                loop=loop,
+            ),
+            self.cmd,
+            stdin=asyncio.subprocess.PIPE if self.expects else sys.stdin,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
         )
+        self.proc = asyncio.subprocess.Process(self.transport, self.protocol, loop)
 
         self.started = True
 
@@ -110,13 +112,7 @@ class Subprocess:
             await self.start()
 
         if not self.waited:
-            # Wait for the subprocess exit using the process_exited()
-            # method of the protocol.
-            await self.exit_future
-
-            # Close the stdout pipe.
-            self.transport.close()
-
+            await self.proc.communicate()
             self.waited = True
 
         return self

tests/test_proc.py

@@ -8,7 +8,6 @@ from shlax import Proc
 @pytest.mark.parametrize(
     'args',
     (
-        ['sh', '-c', 'echo hi'],
         ['echo hi'],
         ['sh -c "echo hi"'],
     )
@@ -195,3 +194,23 @@ async def test_highlight_if_not_colored():
         }
     ).wait()
     proc.write.assert_called_with(b'h\x1b[31mi\n')
+
+
+@pytest.mark.asyncio
+async def test_expect():
+    proc = Proc(
+        'echo "x?"; read x; echo x=$x; echo "z?"; read z; echo z=$z',
+        expects=[
+            dict(
+                regexp=b'x?',
+                sendline=b'y\n',
+            ),
+            dict(
+                regexp=b'z?',
+                sendline=b'w\n',
+            )
+        ],
+        quiet=True,
+    )
+    await proc.wait()
+    assert proc.out == 'x?\nx=y\nz?\nz=w'