Instantiate the thread pool from the outermost layers

CONTRIBUTING.md

@@ -88,10 +88,11 @@ To set up for local development run this command from the root of the repo.
 
 1. Create a file `src/datadoc/.env`
 1. Place the following lines in the file:
-```
-DATADOC_DASH_DEVELOPMENT_MODE=True
-DATADOC_LOG_LEVEL=debug
-```
+
+    ```env
+    DATADOC_DASH_DEVELOPMENT_MODE=True
+    DATADOC_LOG_LEVEL=debug
+    ```
 
 To see all configuration options, see `src/datadoc/config.py`
 

src/datadoc/app.py

@@ -5,6 +5,7 @@
 
 from __future__ import annotations
 
+import concurrent
 import logging
 from pathlib import Path
 
@@ -76,10 +77,13 @@ def build_app(app: type[Dash]) -> Dash:
     return app
 
 
-def get_app(dataset_path: str | None = None) -> tuple[Dash, int]:
+def get_app(
+    executor: concurrent.futures.ThreadPoolExecutor,
+    dataset_path: str | None = None,
+) -> tuple[Dash, int]:
     """Centralize all the ugliness around initializing the app."""
     logger.info("Datadoc version v%s", get_app_version())
-    collect_data_from_external_sources()
+    collect_data_from_external_sources(executor)
     state.current_metadata_language = SupportedLanguages.NORSK_BOKMÅL
     state.metadata = DataDocMetadata(
         state.statistic_subject_mapping,
@@ -114,43 +118,52 @@ def get_app(dataset_path: str | None = None) -> tuple[Dash, int]:
     return app, port
 
 
-def collect_data_from_external_sources() -> None:
+def collect_data_from_external_sources(
+    executor: concurrent.futures.ThreadPoolExecutor,
+) -> None:
     """Call classes and methods which collect data from external sources.
 
     Must be non-blocking to prevent delays in app startup.
     """
+    logger.debug("Start threads - Collecting data from external sources")
     state.statistic_subject_mapping = StatisticSubjectMapping(
+        executor,
         config.get_statistical_subject_source_url(),
     )
 
     state.unit_types = CodeList(
+        executor,
         config.get_unit_code(),
     )
 
     state.organisational_units = CodeList(
+        executor,
         config.get_organisational_unit_code(),
     )
+    logger.debug("Finished blocking - Collecting data from external sources")
 
 
 def main(dataset_path: str | None = None) -> None:
     """Entrypoint when running as a script."""
     if dataset_path:
         logger.info("Starting app with dataset_path = %s", dataset_path)
-    app, port = get_app(dataset_path)
-    if running_in_notebook():
-        logger.info("Running in notebook")
-        app.run(
-            jupyter_mode="tab",
-            jupyter_server_url=config.get_jupyterhub_http_referrer(),
-            jupyter_height=1000,
-            port=port,
-        )
-    else:
-        if dev_mode := config.get_dash_development_mode():
-            logger.warning(
-                "Starting in Development Mode. NOT SUITABLE FOR PRODUCTION.",
+
+    with concurrent.futures.ThreadPoolExecutor(max_workers=12) as executor:
+        app, port = get_app(executor, dataset_path)
+        if running_in_notebook():
+            logger.info("Running in notebook")
+            app.run(
+                jupyter_mode="tab",
+                jupyter_server_url=config.get_jupyterhub_http_referrer(),
+                jupyter_height=1000,
+                port=port,
             )
-        app.run(debug=dev_mode, port=port)
+        else:
+            if dev_mode := config.get_dash_development_mode():
+                logger.warning(
+                    "Starting in Development Mode. NOT SUITABLE FOR PRODUCTION.",
+                )
+            app.run(debug=dev_mode, port=port)
 
 
 if __name__ == "__main__":

src/datadoc/backend/code_list.py

@@ -8,6 +8,8 @@
 from datadoc.enums import SupportedLanguages
 
 if TYPE_CHECKING:
+    import concurrent
+
     import pandas as pd
 
 from klass.classes.classification import KlassClassification
@@ -51,7 +53,11 @@ def get_title(self, language: SupportedLanguages) -> str:
 class CodeList(GetExternalSource):
     """Class for retrieving classifications from Klass."""
 
-    def __init__(self, classification_id: int | None) -> None:
+    def __init__(
+        self,
+        executor: concurrent.futures.ThreadPoolExecutor,
+        classification_id: int | None,
+    ) -> None:
         """Retrieves a list of classifications given a classification id.
 
         Initializes the classifications list and starts fetching the classifications.
@@ -63,7 +69,7 @@ def __init__(self, classification_id: int | None) -> None:
         self._classifications: list[CodeListItem] = []
         self.classification_id = classification_id
         self.classifications_dataframes: dict[str, pd.DataFrame] | None = None
-        super().__init__()
+        super().__init__(executor)
 
     def _fetch_data_from_external_source(
         self,

src/datadoc/backend/external_sources/external_sources.py

@@ -1,12 +1,15 @@
 from __future__ import annotations
 
-import concurrent.futures
 import logging
 from abc import ABC
 from abc import abstractmethod
+from typing import TYPE_CHECKING
 from typing import Generic
 from typing import TypeVar
 
+if TYPE_CHECKING:
+    import concurrent.futures
+
 logger = logging.getLogger(__name__)
 
 T = TypeVar("T")
@@ -15,16 +18,14 @@
 class GetExternalSource(ABC, Generic[T]):
     """Abstract base class for getting data from external sources."""
 
-    def __init__(self) -> None:
+    def __init__(self, executor: concurrent.futures.ThreadPoolExecutor) -> None:
         """Retrieves data from an external source asynchronously.
 
         Initializes the future object.
         """
-        self.future: concurrent.futures.Future[T | None] | None = None
-        with concurrent.futures.ThreadPoolExecutor(max_workers=1) as executor:
-            self.future = executor.submit(
-                self._fetch_data_from_external_source,
-            )
+        self.future = executor.submit(
+            self._fetch_data_from_external_source,
+        )
 
     def wait_for_external_result(self) -> None:
         """Waits for the thread responsible for loading the external request to finish."""

src/datadoc/backend/statistic_subject_mapping.py

@@ -2,6 +2,7 @@
 
 import logging
 from dataclasses import dataclass
+from typing import TYPE_CHECKING
 
 import bs4
 import requests
@@ -11,6 +12,9 @@
 from datadoc.backend.external_sources.external_sources import GetExternalSource
 from datadoc.enums import SupportedLanguages
 
+if TYPE_CHECKING:
+    import concurrent
+
 logger = logging.getLogger(__name__)
 
 
@@ -62,7 +66,11 @@ class PrimarySubject(Subject):
 class StatisticSubjectMapping(GetExternalSource):
     """Allow mapping between statistic short name and primary and secondary subject."""
 
-    def __init__(self, source_url: str | None) -> None:
+    def __init__(
+        self,
+        executor: concurrent.futures.ThreadPoolExecutor,
+        source_url: str | None,
+    ) -> None:
         """Retrieves the statistical structure document from the given URL.
 
         Initializes the mapping dicts. Based on the values in the statistical structure document.
@@ -73,7 +81,7 @@ def __init__(self, source_url: str | None) -> None:
 
         self._primary_subjects: list[PrimarySubject] = []
 
-        super().__init__()
+        super().__init__(executor)
 
     def get_secondary_subject(self, statistic_short_name: str | None) -> str | None:
         """Looks up the secondary subject for the given statistic short name in the mapping dict.

src/datadoc/wsgi.py

@@ -1,6 +1,9 @@
 """Entrypoint for Gunicorn."""
 
+import concurrent
+
 from .app import get_app
 
-datadoc_app, _ = get_app()
-server = datadoc_app.server
+with concurrent.futures.ThreadPoolExecutor(max_workers=12) as executor:
+    datadoc_app, _ = get_app(executor)
+    server = datadoc_app.server

tests/backend/test_code_list.py

@@ -125,7 +125,7 @@ def test_read_dataframe(
     assert code_list_fake_structure.classifications == expected
 
 
-def test_non_existent_code():
-    code_list = CodeList(0)
+def test_non_existent_code(thread_pool_executor):
+    code_list = CodeList(thread_pool_executor, 0)
     code_list.wait_for_external_result()
     assert code_list.classifications == []

tests/backend/test_datadoc_metadata.py

@@ -314,9 +314,13 @@ def test_dataset_status_default_value(
 def test_dataset_assessment_default_value(
     expected_type: Assessment | None,
     copy_dataset_to_path: Path,
+    thread_pool_executor,
 ):
     datadoc_metadata = DataDocMetadata(
-        statistic_subject_mapping=StatisticSubjectMapping(source_url=""),
+        statistic_subject_mapping=StatisticSubjectMapping(
+            thread_pool_executor,
+            source_url="",
+        ),
         dataset_path=str(copy_dataset_to_path),
     )
     assert datadoc_metadata.dataset.assessment == expected_type

tests/backend/test_statistic_subject_mapping.py

@@ -8,8 +8,8 @@
 from tests.utils import TEST_RESOURCES_DIRECTORY
 
 
-def test_no_source_url():
-    subject_mapping = StatisticSubjectMapping(None)
+def test_no_source_url(thread_pool_executor):
+    subject_mapping = StatisticSubjectMapping(thread_pool_executor, None)
     subject_mapping.wait_for_external_result()
     assert subject_mapping.primary_subjects == []
 
@@ -151,12 +151,13 @@ def test_get_secondary_subject(
 def subject_mapping_http_exception(
     requests_mock,
     exception_to_raise,
+    thread_pool_executor,
 ) -> StatisticSubjectMapping:
     requests_mock.get(
         "http://test.some.url.com",
         exc=exception_to_raise,
     )
-    return StatisticSubjectMapping("http://test.some.url.com")
+    return StatisticSubjectMapping(thread_pool_executor, "http://test.some.url.com")
 
 
 @pytest.mark.parametrize(

tests/conftest.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import concurrent
 import copy
 import functools
 import os
@@ -169,11 +170,17 @@ def subject_xml_file_path() -> pathlib.Path:
     )
 
 
+@pytest.fixture()
+def thread_pool_executor() -> concurrent.futures.ThreadPoolExecutor:
+    return concurrent.futures.ThreadPoolExecutor(max_workers=12)
+
+
 @pytest.fixture()
 def subject_mapping_fake_statistical_structure(
     _mock_fetch_statistical_structure,
+    thread_pool_executor,
 ) -> StatisticSubjectMapping:
-    return StatisticSubjectMapping("placeholder")
+    return StatisticSubjectMapping(thread_pool_executor, "placeholder")
 
 
 @pytest.fixture()
@@ -195,12 +202,13 @@ def fake_statistical_structure() -> ResultSet:
 def subject_mapping_http_exception(
     requests_mock,
     exception_to_raise,
+    thread_pool_executor,
 ) -> StatisticSubjectMapping:
     requests_mock.get(
         "http://test.some.url.com",
         exc=exception_to_raise,
     )
-    return StatisticSubjectMapping("http://test.some.url.com")
+    return StatisticSubjectMapping(thread_pool_executor, "http://test.some.url.com")
 
 
 @pytest.fixture()
@@ -239,10 +247,8 @@ def fake_code_list() -> dict[str, pd.DataFrame]:
 
 
 @pytest.fixture()
-def code_list_fake_structure(
-    _mock_fetch_dataframe,
-) -> CodeList:
-    return CodeList(100)
+def code_list_fake_structure(_mock_fetch_dataframe, thread_pool_executor) -> CodeList:
+    return CodeList(thread_pool_executor, 100)
 
 
 @pytest.fixture()

tests/test_smoke.py

@@ -4,10 +4,14 @@
 from datadoc.app import get_app
 
 
-def test_get_app(subject_mapping_fake_statistical_structure, code_list_fake_structure):
+def test_get_app(
+    subject_mapping_fake_statistical_structure,
+    code_list_fake_structure,
+    thread_pool_executor,
+):
     state.statistic_subject_mapping = subject_mapping_fake_statistical_structure
     state.code_list = code_list_fake_structure
 
-    app, _ = get_app()
+    app, _ = get_app(thread_pool_executor)
     assert app.config["name"] == "Datadoc"
     assert len(app.callback_map.items()) > 0