Make model communication non-blocking

PyStemmusScope/bmi/docker_process.py

@@ -1,10 +1,16 @@
 """The Docker STEMMUS_SCOPE model process wrapper."""
 import os
+import socket as pysocket
+import warnings
 from time import sleep
 from typing import Any
 from PyStemmusScope.bmi.docker_utils import check_tags
 from PyStemmusScope.bmi.docker_utils import find_image
 from PyStemmusScope.bmi.docker_utils import make_docker_vols_binds
+from PyStemmusScope.bmi.utils import MATLAB_ERROR
+from PyStemmusScope.bmi.utils import PROCESS_FINALIZED
+from PyStemmusScope.bmi.utils import PROCESS_READY
+from PyStemmusScope.bmi.utils import MatlabError
 from PyStemmusScope.config_io import read_config
 
 
@@ -14,26 +20,64 @@
     docker = None
 
 
+def _model_is_ready(socket: Any, client: Any, container_id: Any) -> None:
+    return _wait_for_model(PROCESS_READY, socket, client, container_id)
+
+
+def _model_is_finalized(socket: Any, client: Any, container_id: Any) -> None:
+    return _wait_for_model(PROCESS_FINALIZED, socket, client, container_id)
+
+
 def _wait_for_model(phrase: bytes, socket: Any, client: Any, container_id: Any) -> None:
     """Wait for the model to be ready to receive (more) commands, or is finalized."""
     output = b""
-    error_msg = b"Error in "
+
     while phrase not in output:
-        if error_msg in output:
+        try:
+            data = socket.read(1)
+        except TimeoutError as err:
             client.stop(container_id)
             logs = client.logs(container_id).decode("utf-8")
-            raise ValueError(
-                f"Error in container '{container_id['Id']}'. Please inspect logs."
-                "\nDOCKER LOGS:\n" + logs
+            msg = (
+                f"Container connection timed out '{container_id['Id']}'."
+                f"\nPlease inspect logs:\n{logs}"
             )
+            raise TimeoutError(msg) from err
 
-        data = socket.read(1)
         if data is None:
             msg = "Could not read data from socket. Docker container might be dead."
             raise ConnectionError(msg)
         else:
             output += bytes(data)
 
+        if MATLAB_ERROR in output:
+            client.stop(container_id)
+            logs = client.logs(container_id).decode("utf-8")
+            msg = (
+                f"Error in container '{container_id['Id']}'.\n"
+                f"Please inspect logs:\n{logs}"
+            )
+            raise MatlabError(msg)
+
+
+def _attach_socket(client, container_id) -> Any:
+    """Attach a socket to a container and add a timeout to it."""
+    connection_timeout = 30  # seconds
+
+    socket = client.attach_socket(container_id, {"stdin": 1, "stdout": 1, "stream": 1})
+    if isinstance(socket, pysocket.SocketIO):
+        socket._sock.settimeout(connection_timeout)  # type: ignore
+    else:
+        warnings.warn(
+            message=(
+                "Unknown socket type found. This might cause issues with the Docker"
+                " connection. \nPlease report this to the developers in an issue "
+                "on: https://github.com/EcoExtreML/STEMMUS_SCOPE_Processing/issues"
+            ),
+            stacklevel=1,
+        )
+    return socket
+
 
 class StemmusScopeDocker:
     """Communicate with a STEMMUS_SCOPE Docker container."""
@@ -68,11 +112,9 @@ def __init__(self, cfg_file: str):
 
         self.running = False
 
-    def wait_for_model(self) -> None:
+    def _wait_for_model(self) -> None:
         """Wait for the model to be ready to receive (more) commands."""
-        _wait_for_model(
-            self._process_ready_phrase, self.socket, self.client, self.container_id
-        )
+        _model_is_ready(self.socket, self.client, self.container_id)
 
     def is_alive(self) -> bool:
         """Return if the process is alive."""
@@ -84,23 +126,22 @@ def initialize(self) -> None:
             self.client.stop(self.container_id)
 
         self.client.start(self.container_id)
-        self.socket = self.client.attach_socket(
-            self.container_id, {"stdin": 1, "stdout": 1, "stream": 1}
-        )
-        self.wait_for_model()
+        self.socket = _attach_socket(self.client, self.container_id)
+
+        self._wait_for_model()
         os.write(
             self.socket.fileno(),
             bytes(f'initialize "{self.cfg_file}"\n', encoding="utf-8"),
         )
-        self.wait_for_model()
+        self._wait_for_model()
 
         self.running = True
 
     def update(self) -> None:
         """Update the model and wait for it to be ready."""
         if self.is_alive():
             os.write(self.socket.fileno(), b"update\n")
-            self.wait_for_model()
+            self._wait_for_model()
         else:
             msg = "Docker container is not alive. Please restart the model."
             raise ConnectionError(msg)
@@ -109,14 +150,14 @@ def finalize(self) -> None:
         """Finalize the model."""
         if self.is_alive():
             os.write(self.socket.fileno(), b"finalize\n")
-            _wait_for_model(
-                self._process_finalized_phrase,
+            _model_is_finalized(
                 self.socket,
                 self.client,
                 self.container_id,
             )
             sleep(0.5)  # Ensure the container can stop cleanly.
             self.client.stop(self.container_id)
+            self.running = False
             self.client.remove_container(self.container_id, v=True)
         else:
             pass

PyStemmusScope/bmi/local_process.py

@@ -1,12 +1,17 @@
 """The local STEMMUS_SCOPE model process wrapper."""
 import os
+import platform
 import subprocess
 from pathlib import Path
+from time import sleep
 from typing import Union
+from PyStemmusScope.bmi.utils import MATLAB_ERROR
+from PyStemmusScope.bmi.utils import PROCESS_READY
+from PyStemmusScope.bmi.utils import MatlabError
 from PyStemmusScope.config_io import read_config
 
 
-def is_alive(process: Union[subprocess.Popen, None]) -> subprocess.Popen:
+def alive_process(process: Union[subprocess.Popen, None]) -> subprocess.Popen:
     """Return process if the process is alive, raise an exception if it is not."""
     if process is None:
         msg = "Model process does not seem to be open."
@@ -17,12 +22,39 @@ def is_alive(process: Union[subprocess.Popen, None]) -> subprocess.Popen:
     return process
 
 
-def wait_for_model(process: subprocess.Popen, phrase=b"Select BMI mode:") -> None:
+def read_stdout(process: subprocess.Popen) -> bytes:
+    """Read from stdout. If the stream ends unexpectedly, an error is raised."""
+    assert process.stdout is not None  # required for type narrowing.
+    read = process.stdout.read(1)
+    if read is None:
+        sleep(5)
+        read = process.stdout.read(1)
+        if read is not None:
+            return bytes(read)
+        msg = "Connection error: could not find expected output or "
+        raise ConnectionError(msg)
+    return bytes(read)
+
+
+def _model_is_ready(process: subprocess.Popen) -> None:
+    return _wait_for_model(PROCESS_READY, process)
+
+
+def _wait_for_model(phrase: bytes, process: subprocess.Popen) -> None:
     """Wait for model to be ready for interaction."""
     output = b""
-    while is_alive(process) and phrase not in output:
-        assert process.stdout is not None  # required for type narrowing.
-        output += bytes(process.stdout.read(1))
+
+    while alive_process(process) and phrase not in output:
+        output += read_stdout(process)
+        if MATLAB_ERROR in output:
+            try:
+                process.terminate()
+            finally:
+                msg = (
+                    "Error encountered in Matlab.\n"
+                    "Please inspect logs in the output directory"
+                )
+                raise MatlabError(msg)
 
 
 def find_exe(config: dict) -> str:
@@ -51,46 +83,73 @@ def __init__(self, cfg_file: str) -> None:
         exe_file = find_exe(config)
         args = [exe_file, cfg_file, "bmi"]
 
-        os.environ["MATLAB_LOG_DIR"] = str(config["InputPath"])
-
-        self.matlab_process = subprocess.Popen(
+        lib_path = os.getenv("LD_LIBRARY_PATH")
+        if lib_path is None:
+            msg = (
+                "Environment variable LD_LIBRARY_PATH not found. "
+                "Refer the Matlab Compiler Runtime documentation"
+            )
+            raise ValueError(msg)
+
+        # Ensure output directory exists so log file can be written:
+        Path(config["OutputPath"]).mkdir(parents=True, exist_ok=True)
+        env = {
+            "LD_LIBRARY_PATH": lib_path,
+            "MATLAB_LOG_DIR": str(config["OutputPath"]),
+        }
+
+        self.process = subprocess.Popen(
             args,
             stdin=subprocess.PIPE,
             stdout=subprocess.PIPE,
             bufsize=0,
+            env=env,
         )
 
-        wait_for_model(self.matlab_process)
+        if platform.system() == "Linux":
+            assert self.process.stdout is not None  # required for type narrowing.
+            # Make the connection non-blocking to allow for a timeout on read.
+            os.set_blocking(self.process.stdout.fileno(), False)
+        else:
+            msg = "Unexpected system. The executable is only compiled for Linux."
+            raise ValueError(msg)
+        _model_is_ready(self.process)
 
     def is_alive(self) -> bool:
         """Return if the process is alive."""
         try:
-            is_alive(self.matlab_process)
+            alive_process(self.process)
             return True
         except ConnectionError:
             return False
 
     def initialize(self) -> None:
         """Initialize the model and wait for it to be ready."""
-        self.matlab_process = is_alive(self.matlab_process)
+        self.process = alive_process(self.process)
 
-        self.matlab_process.stdin.write(  # type: ignore
+        self.process.stdin.write(  # type: ignore
             bytes(f'initialize "{self.cfg_file}"\n', encoding="utf-8")
         )
-        wait_for_model(self.matlab_process)
+        _model_is_ready(self.process)
 
     def update(self) -> None:
         """Update the model and wait for it to be ready."""
-        if self.matlab_process is None:
+        if self.process is None:
             msg = "Run initialize before trying to update the model."
             raise AttributeError(msg)
 
-        self.matlab_process = is_alive(self.matlab_process)
-        self.matlab_process.stdin.write(b"update\n")  # type: ignore
-        wait_for_model(self.matlab_process)
+        self.process = alive_process(self.process)
+        self.process.stdin.write(b"update\n")  # type: ignore
+        _model_is_ready(self.process)
 
     def finalize(self) -> None:
         """Finalize the model."""
-        self.matlab_process = is_alive(self.matlab_process)
-        self.matlab_process.stdin.write(b"finalize\n")  # type: ignore
-        wait_for_model(self.matlab_process, phrase=b"Finished clean up.")
+        self.process = alive_process(self.process)
+        self.process.stdin.write(b"finalize\n")  # type: ignore
+        sleep(10)
+        if self.process.poll() != 0:
+            try:
+                self.process.terminate()
+            finally:
+                msg = f"Model terminated with return code {self.process.poll()}"
+                raise ValueError(msg)

PyStemmusScope/bmi/utils.py

@@ -2,12 +2,24 @@
 import numpy as np
 
 
+# Phrases defined in the Matlab code to check for:
+PROCESS_READY = b"Select BMI mode:"
+PROCESS_FINALIZED = b"Finished clean up."
+MATLAB_ERROR = b"Error in "
+
+
 INAPPLICABLE_GRID_METHOD_MSG = (
     "This grid method is not implmented for the STEMMUS_SCOPE BMI because the model is"
     "\non a rectilinear grid."
 )
 
 
+class MatlabError(Exception):
+    """Matlab code encountered an error."""
+
+    pass
+
+
 class InapplicableBmiMethods:
     """Holds methods that are not applicable for STEMMUS_SCOPE's rectilinear grid."""
 

pyproject.toml

@@ -77,6 +77,7 @@ dev = [
     "mypy",
     "pytest",
     "pytest-cov",
+    "types-requests",  # type stubs
 ]
 docs = [
     "mkdocs",
@@ -143,6 +144,7 @@ extend-select = [
 ignore = [
   "E501",  # Line length: fails on many docstrings (needs fixing).
   "PLR2004",  # magic value used in comparsion (i.e. `if ndays == 28: month_is_feb`).
+  "B009",  # getattr is useful to not mess with typing.
 ]
 line-length = 88
 exclude = ["docs", "build"]