fix(ulimit): handle low ulimit OSError (#2042)

Co-authored-by: Toni de la Fuente <toni@blyx.com>

prowler/lib/check/check.py

@@ -4,6 +4,7 @@ import os
 import sys
 import traceback
 from pkgutil import walk_packages
+from resource import RLIMIT_NOFILE, getrlimit
 from types import ModuleType
 from typing import Any
 
@@ -108,8 +109,8 @@ def exclude_services_to_run(
 # Load checks from checklist.json
 def parse_checks_from_file(input_file: str, provider: str) -> set:
     checks_to_execute = set()
-    f = open_file(input_file)
-    json_file = parse_json_file(f)
+    with open_file(input_file) as f:
+        json_file = parse_json_file(f)
 
     for check_name in json_file[provider]:
         checks_to_execute.add(check_name)
@@ -356,6 +357,13 @@ def execute_checks(
         audit_progress=0,
     )
 
+    # Check ulimit for the maximum system open files
+    soft, _ = getrlimit(RLIMIT_NOFILE)
+    if soft < 4096:
+        logger.warning(
+            f"Your session file descriptors limit ({soft} open files) is below 4096. We recommend to increase it to avoid errors. Solve it running this command `ulimit -n 4096`. For more info visit https://docs.prowler.cloud/en/latest/troubleshooting/"
+        )
+
     # Execution with the --only-logs flag
     if audit_output_options.only_logs:
         for check_name in checks_to_execute:

prowler/lib/utils/utils.py

@@ -16,6 +16,11 @@ from prowler.lib.logger import logger
 def open_file(input_file: str, mode: str = "r") -> TextIOWrapper:
     try:
         f = open(input_file, mode)
+    except OSError:
+        logger.critical(
+            "Ooops! You reached your user session maximum open files. To solve this issue, increase the shell session limit by running this command `ulimit -n 4096`. For more info visit https://docs.prowler.cloud/en/latest/troubleshooting/"
+        )
+        sys.exit(1)
     except Exception as e:
         logger.critical(
             f"{input_file}: {e.__class__.__name__}[{e.__traceback__.tb_lineno}]"

prowler/providers/aws/aws_provider.py

@@ -110,8 +110,8 @@ def generate_regional_clients(
         regional_clients = {}
         # Get json locally
         actual_directory = pathlib.Path(os.path.dirname(os.path.realpath(__file__)))
-        f = open_file(f"{actual_directory}/{aws_services_json_file}")
-        data = parse_json_file(f)
+        with open_file(f"{actual_directory}/{aws_services_json_file}") as f:
+            data = parse_json_file(f)
         # Check if it is a subservice
         json_regions = data["services"][service]["regions"][
             audit_info.audited_partition
@@ -144,8 +144,8 @@ def generate_regional_clients(
 def get_aws_available_regions():
     try:
         actual_directory = pathlib.Path(os.path.dirname(os.path.realpath(__file__)))
-        f = open_file(f"{actual_directory}/{aws_services_json_file}")
-        data = parse_json_file(f)
+        with open_file(f"{actual_directory}/{aws_services_json_file}") as f:
+            data = parse_json_file(f)
 
         regions = set()
         for service in data["services"].values():