Added language_container_activation module

exasol/language_container_activation.py

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+from typing import Dict
+import re
+
+from exasol.secret_store import Secrets
+
+# All secret store entries with language container activation commands
+# will have this common prefix in their keys.
+ACTIVATION_KEY_PREFIX = "language_container_activation_"
+
+
+def get_activation_sql(conf: Secrets) -> str:
+    """
+    Merges multiple language container activation commands found in the secret
+    store and returns a unified command. The resulting activation command will
+    include the union of script languages found in different commands.
+
+    For details on how an activation command may look like please refer to
+    https://docs.exasol.com/db/latest/database_concepts/udf_scripts/adding_new_packages_script_languages.htm
+
+    The secret store entries containing language activation commands should
+    have keys with a common prefix. This prefix is defined in ACTIVATION_KEY_PREFIX.
+
+    The language container activation commands are expected to have overlapping
+    sets of script languages. The urls of script languages with the same alias
+    found in multiple activation commands should be identical, otherwise a
+    RuntimeException will be raised.
+    """
+
+    merged_langs: Dict[str, str] = {}
+    pattern = re.compile(
+        r"\A\s*ALTER\s+SESSION\s+SET\s+SCRIPT_LANGUAGES" r"\s*=\s*'(.+?)'\s*;?\s*\Z",
+        re.IGNORECASE,
+    )
+    # Iterate over all entries that look like language container activation commands.
+    for key, value in conf.items():
+        if key.startswith(ACTIVATION_KEY_PREFIX):
+            # Extract language definitions from the activation command
+            match = pattern.match(value)
+            if match is not None:
+                # Iterate over script languages
+                all_languages = match.group(1)
+                for lang_definition in all_languages.split():
+                    alias, lang_url = lang_definition.split("=", maxsplit=1)
+                    # If this language alias has been encountered before, the url
+                    # must be identical, otherwise the merge fails.
+                    if alias in merged_langs:
+                        if merged_langs[alias].casefold() != lang_url.casefold():
+                            error = (
+                                "Unable to merge multiple language container activation commands. "
+                                f"Found incompatible definitions for the language alias {alias}."
+                            )
+                            raise RuntimeError(error)
+                    else:
+                        merged_langs[alias] = lang_url
+
+    # Build and return a new SQL command for merged language container activation.
+    merged_langs_str = " ".join(f"{key}={value}" for key, value in merged_langs.items())
+    return f"ALTER SESSION SET SCRIPT_LANGUAGES='{merged_langs_str}';"

test/unit/test_language_container_activation.py

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+import re
+
+import pytest
+
+from exasol.language_container_activation import (
+    ACTIVATION_KEY_PREFIX,
+    get_activation_sql,
+)
+
+
+def test_get_activation_sql(secrets):
+    secrets.save(
+        ACTIVATION_KEY_PREFIX + "_lang1",
+        "ALTER SESSION SET SCRIPT_LANGUAGES='"
+        "R=builtin_r JAVA=builtin_java PYTHON3=builtin_python3 "
+        "FIRST_LANG=localzmq+protobuf:///bfs_path1?"
+        "lang=python#/buckets/bfs_path1/exaudf/exaudfclient_py3';",
+    )
+
+    secrets.save("some_other_key", "some_other_value")
+
+    secrets.save(
+        ACTIVATION_KEY_PREFIX + "_lang2",
+        "ALTER SESSION SET SCRIPT_LANGUAGES='"
+        "R=builtin_r JAVA=builtin_java PYTHON3=builtin_python3 "
+        "SECOND_LANG=localzmq+protobuf:///bfs_path2?"
+        "lang=python#/buckets/bfs_path2/exaudf/exaudfclient_py3';",
+    )
+
+    sql = get_activation_sql(secrets)
+    match = re.match(
+        r"\A\s*ALTER\s+SESSION\s+SET\s+SCRIPT_LANGUAGES\s*=\s*'(.+?)'\s*;?\s*\Z",
+        sql,
+        re.IGNORECASE,
+    )
+    assert match is not None
+    lang_defs = set(match.group(1).split())
+    expected_lang_defs = {
+        "R=builtin_r",
+        "JAVA=builtin_java",
+        "PYTHON3=builtin_python3",
+        "FIRST_LANG=localzmq+protobuf:///bfs_path1?"
+        "lang=python#/buckets/bfs_path1/exaudf/exaudfclient_py3",
+        "SECOND_LANG=localzmq+protobuf:///bfs_path2?"
+        "lang=python#/buckets/bfs_path2/exaudf/exaudfclient_py3",
+    }
+    assert lang_defs == expected_lang_defs
+
+
+def test_get_activation_sql_failure(secrets):
+    secrets.save(
+        ACTIVATION_KEY_PREFIX + "_lang1",
+        "ALTER SESSION SET SCRIPT_LANGUAGES='"
+        "R=builtin_r JAVA=builtin_java PYTHON3=builtin_python3 "
+        "LANG_ABC=localzmq+protobuf:///bfs_path1?"
+        "lang=python#/buckets/bfs_path1/exaudf/exaudfclient_py3';",
+    )
+
+    secrets.save("some_other_key", "some_other_value")
+
+    secrets.save(
+        ACTIVATION_KEY_PREFIX + "_lang2",
+        "ALTER SESSION SET SCRIPT_LANGUAGES='"
+        "R=builtin_r JAVA=builtin_java PYTHON3=builtin_python3 "
+        "LANG_ABC=localzmq+protobuf:///bfs_path2?"
+        "lang=python#/buckets/bfs_path2/exaudf/exaudfclient_py3';",
+    )
+
+    with pytest.raises(RuntimeError):
+        get_activation_sql(secrets)