passio: Implement exercise

config.json

@@ -1482,6 +1482,18 @@
         "loops"
       ]
     },
+    {
+      "slug": "paasio",
+      "uuid": "ec36f9ed-f376-43d9-90ee-be0bea0cfc98",
+      "core": false,
+      "unlocked_by": "book-store",
+      "difficulty": 5,
+      "topics": [
+        "classes",
+        "interfaces",
+        "networking"
+      ]
+    },
     {
       "slug": "accumulate",
       "uuid": "e7351e8e-d3ff-4621-b818-cd55cf05bffd",

exercises/paasio/README.md

@@ -0,0 +1,60 @@
+# PaaS I/O
+
+Report network IO statistics.
+
+You are writing a [PaaS][], and you need a way to bill customers based
+on network and filesystem usage.
+
+Create a wrapper for network connections and files that can report IO
+statistics. The wrapper must report:
+
+- The total number of bytes read/written.
+- The total number of read/write operations.
+
+[PaaS]: http://en.wikipedia.org/wiki/Platform_as_a_service
+
+## Exception messages
+
+Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
+indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
+every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
+a message.
+
+To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
+`raise Exception`, you should write:
+
+```python
+raise Exception("Meaningful message indicating the source of the error")
+```
+
+## Running the tests
+
+To run the tests, run `pytest paasio_test.py`
+
+Alternatively, you can tell Python to run the pytest module:
+`python -m pytest paasio_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/paasio` directory.
+
+You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
+
+For more detailed information about running tests, code style and linting,
+please see [Running the Tests](http://exercism.io/tracks/python/tests).
+
+## Source
+
+Brian Matsuo [https://github.com/bmatsuo](https://github.com/bmatsuo)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/paasio/example.py

@@ -0,0 +1,102 @@
+import io
+
+
+class MeteredFile(io.BufferedRandom):
+    """Implement using a subclassing model."""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._read_bytes = 0
+        self._read_ops = 0
+        self._write_bytes = 0
+        self._write_ops = 0
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        return super().__exit__(exc_type, exc_val, exc_tb)
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        self._read_ops += 1
+        data = super().readline()
+        self._read_bytes += len(data)
+        if data:
+            return data
+        raise StopIteration
+
+    def read(self, size=-1):
+        self._read_ops += 1
+        data = super().read(size)
+        self._read_bytes += len(data)
+        return data
+
+    @property
+    def read_bytes(self):
+        return self._read_bytes
+
+    @property
+    def read_ops(self):
+        return self._read_ops
+
+    def write(self, b):
+        self._write_ops += 1
+        length = super().write(b)
+        self._write_bytes += length
+        return length
+
+    @property
+    def write_bytes(self):
+        return self._write_bytes
+
+    @property
+    def write_ops(self):
+        return self._write_ops
+
+
+class MeteredSocket:
+    """Implement using a delegation model."""
+
+    def __init__(self, socket):
+        self._socket = socket
+        self._recv_bytes = 0
+        self._recv_ops = 0
+        self._send_bytes = 0
+        self._send_ops = 0
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        return self._socket.__exit__(exc_type, exc_val, exc_tb)
+
+    def recv(self, bufsize, flags=0):
+        self._recv_ops += 1
+        data = self._socket.recv(bufsize, flags)
+        self._recv_bytes += len(data)
+        return data
+
+    @property
+    def recv_bytes(self):
+        return self._recv_bytes
+
+    @property
+    def recv_ops(self):
+        return self._recv_ops
+
+    def send(self, data, flags=0):
+        self._send_ops += 1
+        length = self._socket.send(data, flags)
+        self._send_bytes += length
+        return length
+
+    @property
+    def send_bytes(self):
+        return self._send_bytes
+
+    @property
+    def send_ops(self):
+        return self._send_ops

exercises/paasio/paasio.py

@@ -0,0 +1,77 @@
+import io
+
+
+class MeteredFile(io.BufferedRandom):
+    """Implement using a subclassing model."""
+
+    def __init__(self, *args, **kwargs):
+        pass
+
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        pass
+
+    def __iter__(self):
+        pass
+
+    def __next__(self):
+        pass
+
+    def read(self, size=-1):
+        pass
+
+    @property
+    def read_bytes(self):
+        pass
+
+    @property
+    def read_ops(self):
+        pass
+
+    def write(self, b):
+        pass
+
+    @property
+    def write_bytes(self):
+        pass
+
+    @property
+    def write_ops(self):
+        pass
+
+
+class MeteredSocket:
+    """Implement using a delegation model."""
+
+    def __init__(self, socket):
+        pass
+
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        pass
+
+    def recv(self, bufsize, flags=0):
+        pass
+
+    @property
+    def recv_bytes(self):
+        pass
+
+    @property
+    def recv_ops(self):
+        pass
+
+    def send(self, data, flags=0):
+        pass
+
+    @property
+    def send_bytes(self):
+        pass
+
+    @property
+    def send_ops(self):
+        pass