feat: Composite startup verbs for the flagsmith entrypoint

README.md

@@ -35,6 +35,33 @@ This enables the `route` label for Prometheus HTTP metrics.
 
 5. To enable the `/metrics` endpoint, set the `PROMETHEUS_ENABLED` setting to `True`.
 
+### Startup commands
+
+`common.core` registers composite startup verbs on the `flagsmith` command, so a container entrypoint can sequence startup itself rather than via a shell script:
+
+- `flagsmith serve` — wait for the database, then start the API.
+- `flagsmith migrate` — migrate each configured database, then create the cache table. A bare invocation runs the full sequence; `flagsmith migrate <app> <name>` defers to Django for targeted migrations.
+- `flagsmith run-task-processor` — migrate, wait for migrations to be applied, then start the Task Processor.
+- `flagsmith migrate-and-serve` — migrate, run any configured startup commands, then start the API.
+
+The verbs are configured through these settings:
+
+| Setting | Default | Purpose |
+| --- | --- | --- |
+| `FLAGSMITH_MIGRATE_DATABASES` | `["default"]` | Database aliases the `migrate` step applies, in order. |
+| `FLAGSMITH_WAIT_FOR_MIGRATIONS_DATABASES` | `["default"]` | Database aliases `run-task-processor` waits on before starting. |
+| `FLAGSMITH_STARTUP_COMMANDS` | `[]` | Management commands run, in order, between migrate and serve in `migrate-and-serve`. |
+
+…and these environment variables:
+
+| Environment variable | Default | Purpose |
+| --- | --- | --- |
+| `SKIP_WAIT_FOR_DB` | unset | When set, skip waiting for the database. |
+| `TASK_PROCESSOR_NUM_THREADS` | `5` | Number of worker threads. |
+| `TASK_PROCESSOR_SLEEP_INTERVAL_MS` | `500` | Millis each worker waits before checking for new tasks (falls back to `TASK_PROCESSOR_SLEEP_INTERVAL`). |
+| `TASK_PROCESSOR_GRACE_PERIOD_MS` | `20000` | Millis before a running task is considered stuck. |
+| `TASK_PROCESSOR_QUEUE_POP_SIZE` | `10` | Tasks each worker pops from the queue per cycle. |
+
 ### Pre-commit hooks
 
 This repo provides a [`flagsmith-lint-tests`](.pre-commit-hooks.yaml) hook that enforces test conventions:

pyproject.toml

@@ -37,6 +37,7 @@ optional-dependencies = { test-tools = [
     "backoff (>=2.2.1,<3.0.0)",
     "django (>4,<6)",
     "django-health-check",
+    "environs (<16)",
     "opentelemetry-api (>=1.25,<2)",
     "prometheus-client (>=0.0.16)",
 ], flagsmith-schemas = [

src/common/core/cli/run.py

@@ -0,0 +1,79 @@
+"""Composite startup verbs for the `flagsmith` entrypoint.
+
+These mirror the sequencing that Core API's `run-docker.sh` performed in
+shell, but run in a single process so the Django boot cost is paid once.
+"""
+
+import os
+import shlex
+
+from django.conf import settings
+from django.core.management import (
+    execute_from_command_line as django_execute_from_command_line,
+)
+
+WAIT_FOR_MIGRATIONS_TIMEOUT_SECONDS = 30
+
+
+def _wait_for_db(
+    *,
+    wait_for_migrations: bool = False,
+    database: str = "default",
+    wait_for: int | None = None,
+) -> None:
+    if os.environ.get("SKIP_WAIT_FOR_DB"):
+        return
+    args = ["waitfordb", "--database", database]
+    if wait_for is not None:
+        args += ["--waitfor", str(wait_for)]
+    if wait_for_migrations:
+        args.append("--migrations")
+    django_execute_from_command_line(["flagsmith", *args])
+
+
+def _migrate() -> None:
+    _wait_for_db()
+    databases: list[str] = getattr(settings, "FLAGSMITH_MIGRATE_DATABASES", ["default"])
+    for database in databases:
+        django_execute_from_command_line(
+            ["flagsmith", "migrate", "--database", database]
+        )
+    django_execute_from_command_line(["flagsmith", "createcachetable"])
+
+
+def migrate(argv: list[str], *, prog: str) -> None:
+    """Migrate the configured databases, then create the cache table."""
+    if argv:
+        django_execute_from_command_line(["flagsmith", "migrate", *argv])
+        return
+    _migrate()
+
+
+def serve(argv: list[str], *, prog: str) -> None:
+    """Wait for the database, then start the API server."""
+    _wait_for_db()
+    django_execute_from_command_line(["flagsmith", "start", "api", *argv])
+
+
+def run_task_processor(argv: list[str], *, prog: str) -> None:
+    """Migrate, wait for migrations to be applied, then start the task processor."""
+    _migrate()
+    databases: list[str] = getattr(
+        settings, "FLAGSMITH_WAIT_FOR_MIGRATIONS_DATABASES", ["default"]
+    )
+    for database in databases:
+        _wait_for_db(
+            wait_for_migrations=True,
+            database=database,
+            wait_for=WAIT_FOR_MIGRATIONS_TIMEOUT_SECONDS,
+        )
+    django_execute_from_command_line(["flagsmith", "start", "task-processor", *argv])
+
+
+def migrate_and_serve(argv: list[str], *, prog: str) -> None:
+    """Migrate, run any configured startup commands, then start the API server."""
+    _migrate()
+    startup_commands: list[str] = getattr(settings, "FLAGSMITH_STARTUP_COMMANDS", [])
+    for command in startup_commands:
+        django_execute_from_command_line(["flagsmith", *shlex.split(command)])
+    django_execute_from_command_line(["flagsmith", "start", "api", *argv])

src/common/core/main.py

@@ -10,7 +10,7 @@
 )
 from environs import Env
 
-from common.core.cli import healthcheck
+from common.core.cli import healthcheck, run
 from common.core.logging import setup_logging
 from common.gunicorn.processors import make_gunicorn_access_processor
 
@@ -118,6 +118,11 @@ def execute_from_command_line(argv: list[str]) -> None:
             # Backwards compatibility for task-processor health checks
             # See https://github.com/Flagsmith/flagsmith-task-processor/issues/24
             "checktaskprocessorthreadhealth": healthcheck.main,
+            # Composite startup verbs, formerly run-docker.sh
+            "serve": run.serve,
+            "migrate": run.migrate,
+            "run-task-processor": run.run_task_processor,
+            "migrate-and-serve": run.migrate_and_serve,
         }[subcommand]
     except (IndexError, KeyError):
         logger.info("Invoking Django")

src/task_processor/utils.py

@@ -4,11 +4,15 @@
 from contextlib import contextmanager
 from typing import Any, Generator
 
+from environs import Env
+
 from task_processor.threads import TaskRunnerCoordinator
 from task_processor.types import TaskCallable, TaskProcessorConfig
 
 logger = logging.getLogger(__name__)
 
+env = Env()
+
 
 def get_task_identifier_from_function(
     function: TaskCallable[Any],
@@ -24,25 +28,28 @@ def add_arguments(parser: argparse.ArgumentParser) -> None:
         "--numthreads",
         type=int,
         help="Number of worker threads to run.",
-        default=5,
+        default=env.int("TASK_PROCESSOR_NUM_THREADS", 5),
     )
     parser.add_argument(
         "--sleepintervalms",
         type=int,
         help="Number of millis each worker waits before checking for new tasks",
-        default=2000,
+        default=env.int(
+            "TASK_PROCESSOR_SLEEP_INTERVAL_MS",
+            env.int("TASK_PROCESSOR_SLEEP_INTERVAL", 500),
+        ),
     )
     parser.add_argument(
         "--graceperiodms",
         type=int,
         help="Number of millis before running task is considered 'stuck'.",
-        default=20000,
+        default=env.int("TASK_PROCESSOR_GRACE_PERIOD_MS", 20000),
     )
     parser.add_argument(
         "--queuepopsize",
         type=int,
         help="Number of tasks each worker will pop from the queue on each cycle.",
-        default=10,
+        default=env.int("TASK_PROCESSOR_QUEUE_POP_SIZE", 10),
     )
 
 

tests/unit/common/core/test_main.py

@@ -6,7 +6,7 @@
 from pytest_mock import MockerFixture
 from structlog.typing import Processor
 
-from common.core.main import ensure_cli_env
+from common.core.main import ensure_cli_env, execute_from_command_line
 from common.core.otel import add_otel_trace_context
 
 
@@ -252,3 +252,45 @@ def test_ensure_cli_env__env_service_name__expected_otel_service_name(
         endpoint="http://collector:4318/v1/traces",
         service_name="my-custom",
     )
+
+
+@pytest.mark.parametrize(
+    "subcommand,handler_name",
+    [
+        pytest.param("serve", "serve", id="serve"),
+        pytest.param("migrate", "migrate", id="migrate"),
+        pytest.param(
+            "run-task-processor", "run_task_processor", id="run_task_processor"
+        ),
+        pytest.param("migrate-and-serve", "migrate_and_serve", id="migrate_and_serve"),
+    ],
+)
+def test_execute_from_command_line__startup_verb__routes_to_run_handler(
+    mocker: MockerFixture,
+    subcommand: str,
+    handler_name: str,
+) -> None:
+    # Given
+    mock_handler = mocker.patch(f"common.core.cli.run.{handler_name}")
+
+    # When
+    execute_from_command_line(["flagsmith", subcommand, "--extra", "arg"])
+
+    # Then
+    mock_handler.assert_called_once_with(
+        ["--extra", "arg"],
+        prog=f"flagsmith {subcommand}",
+    )
+
+
+def test_execute_from_command_line__unknown_subcommand__invokes_django(
+    mocker: MockerFixture,
+) -> None:
+    # Given
+    mock_django = mocker.patch("common.core.main.django_execute_from_command_line")
+
+    # When
+    execute_from_command_line(["flagsmith", "showmigrations"])
+
+    # Then
+    mock_django.assert_called_once_with(["flagsmith", "showmigrations"])