fix: Improve and fix codejail service integration

Address recommendations and fixes discussed in PR.
Use similar structure to notes app.
Fix errors detected in tests.

common/lib/capa/capa/safe_exec/exceptions.py

@@ -0,0 +1,24 @@
+"""
+Exceptions related to safe exec.
+"""
+
+
+class CodejailServiceParseError(Exception):
+    """
+    An exception that is raised whenever we have issues with data parsing.
+    """
+    pass  # lint-amnesty, pylint: disable=unnecessary-pass
+
+
+class CodejailServiceStatusError(Exception):
+    """
+    An exception that is raised whenever Codejail service response status is different to 200.
+    """
+    pass  # lint-amnesty, pylint: disable=unnecessary-pass
+
+
+class CodejailServiceUnavailable(Exception):
+    """
+    An exception that is raised whenever Codejail service is unavailable.
+    """
+    pass  # lint-amnesty, pylint: disable=unnecessary-pass

common/lib/capa/capa/safe_exec/helpers.py

@@ -0,0 +1,97 @@
+"""
+Helper methods related to safe exec.
+"""
+
+import requests
+import json
+import logging
+
+from codejail.safe_exec import SafeExecException
+from django.conf import settings
+from django.utils.translation import ugettext as _
+from edx_toggles.toggles import SettingDictToggle
+from requests.exceptions import RequestException, HTTPError
+from simplejson import JSONDecodeError
+
+from .exceptions import CodejailServiceParseError, CodejailServiceStatusError, CodejailServiceUnavailable
+
+log = logging.getLogger(__name__)
+
+# .. toggle_name: ENABLE_CODEJAIL_REST_SERVICE
+# .. toggle_implementation: DjangoSetting
+# .. toggle_default: False
+# .. toggle_description: Set this to True if you want to run Codejail code using
+#   a separate VM or container and communicate with edx-platform using REST API.
+# .. toggle_use_cases: open_edx
+# .. toggle_creation_date: 2021-08-19
+# .. toggle_target_removal_date: None
+# .. toggle_warnings:
+# .. toggle_tickets:
+ENABLE_CODEJAIL_REST_SERVICE = SettingDictToggle(
+    "FEATURES", "ENABLE_CODEJAIL_REST_SERVICE", default=False, module_name=__name__
+)
+
+
+def is_codejail_rest_service_enabled():
+    return ENABLE_CODEJAIL_REST_SERVICE.is_enabled()
+
+
+def get_codejail_rest_service_endpoint():
+    return "".join([
+        settings.CODE_JAIL_REST_SERVICE_HOST,
+        "/api/v0/code-exec"])
+
+
+def send_safe_exec_request(data, extra_files):
+    """
+    Sends a request to a codejail api service forwarding required code and files.
+    Arguments:
+        data: Dict containing code and othe parameters
+            required for jailed code execution.
+        extra_files: python_lib.zip file containing extra files
+            required by the codejail execution.
+    Returns:
+        Response received from codejsail api service
+    """
+    globals_dict = data["globals_dict"]
+
+    codejail_service_endpoint = get_codejail_rest_service_endpoint()
+    payload = json.dumps(data)
+
+    try:
+        response = requests.post(
+            codejail_service_endpoint,
+            files=extra_files,
+            data={'payload': payload},
+            timeout=(settings.CODE_JAIL_REST_SERVICE_CONNECT_TIMEOUT, settings.CODE_JAIL_REST_SERVICE_READ_TIMEOUT)
+        )
+
+    except RequestException:
+        log.error("Failed to connect to codejail api service: url=%s, params=%s",
+                  codejail_service_endpoint, str(payload))
+        raise CodejailServiceUnavailable(_("Codejail API Service is unavailable. Please try again in a few minutes."))  # lint-amnesty, pylint: disable=raise-missing-from
+
+    try:
+        response.raise_for_status()
+    except HTTPError:
+        raise CodejailServiceStatusError(_("Codejail API Service invalid response."))  # lint-amnesty, pylint: disable=raise-missing-from
+
+    try:
+        response_json = response.json()
+    except JSONDecodeError:
+        log.error("Invalid JSON response received from codejail api service: Response_Content=%s", response.content)
+        raise CodejailServiceParseError(_("Invalid JSON response received from codejail api service."))  # lint-amnesty, pylint: disable=raise-missing-from
+
+    emsg = response_json.get("emsg")
+    exception = None
+
+    if emsg:
+        exception_msg = ". ".join([
+            emsg,
+            "For more information check Codejail Service logs."])
+
+        exception = SafeExecException(exception_msg)
+
+    globals_dict.update(response_json.get("globals_dict"))
+
+    return emsg, exception

common/lib/capa/capa/safe_exec/safe_exec.py

@@ -2,18 +2,16 @@
 
 
 import hashlib
-import requests
-import json
 
 from codejail.safe_exec import SafeExecException, json_safe
 from codejail.safe_exec import not_safe_exec as codejail_not_safe_exec
 from codejail.safe_exec import safe_exec as codejail_safe_exec
-from django.conf import settings
 from edx_django_utils.monitoring import function_trace
 import six
 from six import text_type
 
 from . import lazymod
+from .helpers import is_codejail_rest_service_enabled, send_safe_exec_request
 
 # Establish the Python environment for Capa.
 # Capa assumes float-friendly division always.
@@ -146,40 +144,18 @@ def safe_exec(
     # Create the complete code we'll run.
     code_prolog = CODE_PROLOG % random_seed
 
-    if settings.FEATURES.get('ENABLE_CODEJAIL_REST_SERVICE', False):
-        try:
-            codejail_service_endpoint = "".join([
-                settings.CODE_JAIL_REST_SERVICE_HOST,
-                "/api/v0/code-exec"
-                ])
-            data = {
-                "code": code_prolog + LAZY_IMPORTS + code,
-                "globals_dict": globals_dict,
-                "python_path": python_path,
-                "limit_overrides_context": limit_overrides_context,
-                "slug": slug,
-                "unsafely": unsafely
-            }
-            datajson = json.dumps(data)
-            response = requests.request(
-                "POST",
-                codejail_service_endpoint,
-                files=extra_files,
-                data={'payload': datajson}
-            )
-            response_json = response.json()
-            emsg = response_json["emsg"]
-            if emsg:
-                exception_msg = ". ".join([
-                        emsg,
-                        "For more information check Codejail Service logs."
-                    ])
-                
-                exception = SafeExecException(emsg)
-            globals_dict.update(response_json["globals_dict"])
-        except Exception as e:
-            raise e
-            emsg = None
+    if is_codejail_rest_service_enabled():
+        data = {
+            "code": code_prolog + LAZY_IMPORTS + code,
+            "globals_dict": globals_dict,
+            "python_path": python_path,
+            "limit_overrides_context": limit_overrides_context,
+            "slug": slug,
+            "unsafely": unsafely
+        }
+
+        emsg, exception = send_safe_exec_request(data, extra_files)
+
     else:
         # Decide which code executor to use.
         if unsafely:

lms/envs/common.py

@@ -948,17 +948,17 @@ FEATURES = {
     # .. toggle_target_removal_date: 2021-10-01
     # .. toggle_tickets: 'https://openedx.atlassian.net/browse/MICROBA-1405'
     'ENABLE_V2_CERT_DISPLAY_SETTINGS': False,
-    
+
     # .. toggle_name: ENABLE_CODEJAIL_REST_SERVICE
     # .. toggle_implementation: DjangoSetting
     # .. toggle_default: False
     # .. toggle_description: Set this to True if you want to run Codejail code using
     #   a separate VM or container and communicate with edx-platform using REST API.
-    # .. toggle_use_cases: tutor
+    # .. toggle_use_cases: open_edx
     # .. toggle_creation_date: 2021-08-19
     # .. toggle_target_removal_date: None
-    # .. toggle_warnings: 
-    # .. toggle_tickets: 
+    # .. toggle_warnings:
+    # .. toggle_tickets:
     'ENABLE_CODEJAIL_REST_SERVICE': False,
 }
 
@@ -1643,6 +1643,9 @@ COURSES_WITH_UNSAFE_CODE = []
 
 # Cojail REST service
 CODE_JAIL_REST_SERVICE_HOST = 'http://127.0.0.1:8550'
+CODE_JAIL_REST_SERVICE_CONNECT_TIMEOUT = 0.5  # time in seconds
+CODE_JAIL_REST_SERVICE_READ_TIMEOUT = 3.5  # time in seconds
+
 
 ############################### DJANGO BUILT-INS ###############################
 # Change DEBUG in your environment settings files, not here