fix: Decoding non-unicode characters raises unhandled exception

aws_lambda_builders/utils.py

@@ -1,7 +1,7 @@
 """
 Common utilities for the library
 """
-
+import locale
 import logging
 import os
 import shutil
@@ -231,3 +231,28 @@ def extract_tarfile(tarfile_path: Union[str, os.PathLike], unpack_dir: Union[str
                 raise tarfile.ExtractError("Attempted Path Traversal in Tar File")
 
         tar.extractall(unpack_dir)
+
+
+def decode(to_decode: bytes, encoding: Optional[str] = None) -> str:
+    """
+    Perform a "safe" decoding of a series of bytes. If the decoding works, returns the decoded bytes.
+    If the decoding fails, returns an empty string instead of throwing an exception.
+
+    Parameters
+    ----------
+    to_decode: bytes
+        Series of bytes to be decoded
+    encoding: Optional[str]
+        Encoding type. If None, will attempt to find the correct encoding based on locale.
+
+    Returns
+    -------
+    str
+       Decoded string if decoding succeeds, empty string if decoding fails
+    """
+    encoding = encoding if encoding else locale.getpreferredencoding()
+    try:
+        return to_decode.decode(encoding).strip()
+    except UnicodeDecodeError:
+        LOG.debug(f"Unable to decode bytes: {to_decode} with encoding: {encoding}")
+    return ""

aws_lambda_builders/workflows/dotnet_clipackage/dotnetcli.py

@@ -2,10 +2,10 @@
 Wrapper around calls to dotent CLI through a subprocess.
 """
 
-import locale
 import logging
 
-from .utils import OSUtils
+from aws_lambda_builders.utils import decode
+from aws_lambda_builders.workflows.dotnet_clipackage.utils import OSUtils
 
 LOG = logging.getLogger(__name__)
 
@@ -52,15 +52,14 @@ def run(self, args, cwd=None):
         # DotNet output is in system locale dependent encoding
         # https://learn.microsoft.com/en-us/dotnet/api/system.console.outputencoding?view=net-6.0#remarks
         # "The default code page that the console uses is determined by the system locale."
-        encoding = locale.getpreferredencoding()
         p = self.os_utils.popen(invoke_dotnet, stdout=self.os_utils.pipe, stderr=self.os_utils.pipe, cwd=cwd)
 
         out, err = p.communicate()
 
         # The package command contains lots of useful information on how the package was created and
         # information when the package command was not successful. For that reason the output is
         # always written to the output to help developers diagnose issues.
-        LOG.info(out.decode(encoding).strip())
+        LOG.info(decode(out))
 
         if p.returncode != 0:
-            raise DotnetCLIExecutionError(message=err.decode(encoding).strip())
+            raise DotnetCLIExecutionError(message=decode(err))

aws_lambda_builders/workflows/dotnet_clipackage/utils.py

@@ -7,7 +7,7 @@
 import subprocess
 import zipfile
 
-from aws_lambda_builders.utils import which
+from aws_lambda_builders.utils import decode, which
 
 LOG = logging.getLogger(__name__)
 
@@ -96,7 +96,7 @@ def _extract(self, file_info, output_dir, zip_ref):
         if not self._is_symlink(file_info):
             return zip_ref.extract(file_info, output_dir)
 
-        source = zip_ref.read(file_info.filename).decode("utf8")
+        source = decode(zip_ref.read(file_info.filename))
         link_name = os.path.normpath(os.path.join(output_dir, file_info.filename))
 
         # make leading dirs if needed

aws_lambda_builders/workflows/java_gradle/gradle_validator.py

@@ -5,6 +5,7 @@
 import logging
 import re
 
+from aws_lambda_builders.utils import decode
 from aws_lambda_builders.validator import RuntimeValidator
 from aws_lambda_builders.workflows.java.utils import OSUtils
 
@@ -81,6 +82,6 @@ def _get_jvm_string(self, gradle_path):
             return None
 
         for line in stdout.splitlines():
-            l_dec = line.decode()
+            l_dec = decode(line)
             if l_dec.startswith("JVM"):
                 return l_dec

aws_lambda_builders/workflows/java_maven/maven.py

@@ -5,6 +5,8 @@
 import logging
 import subprocess
 
+from aws_lambda_builders.utils import decode
+
 LOG = logging.getLogger(__name__)
 
 
@@ -28,10 +30,10 @@ def build(self, scratch_dir):
         args = ["clean", "install"]
         ret_code, stdout, _ = self._run(args, scratch_dir)
 
-        LOG.debug("Maven logs: %s", stdout.decode("utf8").strip())
+        LOG.debug("Maven logs: %s", decode(stdout))
 
         if ret_code != 0:
-            raise MavenExecutionError(message=stdout.decode("utf8").strip())
+            raise MavenExecutionError(message=decode(stdout))
 
     def copy_dependency(self, scratch_dir):
         include_scope = "runtime"
@@ -40,7 +42,7 @@ def copy_dependency(self, scratch_dir):
         ret_code, stdout, _ = self._run(args, scratch_dir)
 
         if ret_code != 0:
-            raise MavenExecutionError(message=stdout.decode("utf8").strip())
+            raise MavenExecutionError(message=decode(stdout))
 
     def _run(self, args, cwd=None):
         p = self.os_utils.popen(

tests/unit/test_utils.py

@@ -1,7 +1,10 @@
+import platform
+
 from unittest import TestCase
 from unittest.mock import patch
 
 from aws_lambda_builders import utils
+from aws_lambda_builders.utils import decode
 
 
 class Test_create_symlink_or_copy(TestCase):
@@ -30,3 +33,29 @@ def test_must_copy_if_symlink_fails(self, patched_copy_tree, pathced_os, patched
 
         pathced_os.symlink.assert_called_once()
         patched_copy_tree.assert_called_with(source_path, destination_path)
+
+
+class TestDecode(TestCase):
+    def test_does_not_crash_non_utf8_encoding(self):
+        message = "hello\n\n ß".encode("iso-8859-1")
+        # Windows will decode this string as expected, *nix systems won't
+        expected_message = "hello\n\n ß" if platform.system().lower() == "windows" else ""
+        response = decode(message)
+        self.assertEqual(response, expected_message)
+
+    def test_is_able_to_decode_non_utf8_encoding(self):
+        message = "hello\n\n ß".encode("iso-8859-1")
+        response = decode(message, "iso-8859-1")
+        self.assertEqual(response, "hello\n\n ß")
+
+    @patch("aws_lambda_builders.utils.locale")
+    def test_isa_able_to_decode_non_utf8_locale(self, mock_locale):
+        mock_locale.getpreferredencoding.return_value = "iso-8859-1"
+        message = "hello\n\n ß".encode("iso-8859-1")
+        response = decode(message)
+        self.assertEqual(response, "hello\n\n ß")
+
+    def test_succeeds_with_utf8_encoding(self):
+        message = "hello".encode("utf-8")
+        response = decode(message)
+        self.assertEqual(response, "hello")