Create db if doesn't exist (#37)

* provides a mechanism for database initialization within the container image

* only create file if it doesn't exist yet

* rootless -> root container because of Litestream permissions issues

I have no idea why, but Litestream sets a replicated file's
permissions to 600 [0], which makes it impossible to access
from a rootless container, if the file is being exposed through
a volume.

[0] https://github.com/benbjohnson/litestream/blob/5be467a478adcffc5b3999b9503cc676c2bf09f1/internal/internal.go#L62

* init db within __main__.py instead of outside script

Dockerfile

@@ -13,8 +13,9 @@ COPY requirements.txt /requirements.txt
 RUN /venv/bin/pip install --disable-pip-version-check -r /requirements.txt
 
 # Copy the virtualenv into a distroless image
-FROM gcr.io/distroless/python3-debian12:nonroot
+FROM gcr.io/distroless/python3-debian12:latest
 COPY --from=build /venv /venv
 COPY ./gantry /app/gantry
+COPY ./db /app/db
 WORKDIR /app
 ENTRYPOINT ["/venv/bin/python", "-m", "gantry"]

db/schema.sql

@@ -1,6 +1,6 @@
 PRAGMA foreign_keys = ON;
 
-CREATE TABLE nodes (
+CREATE TABLE IF NOT EXISTS nodes (
     id INTEGER PRIMARY KEY,
     uuid TEXT NOT NULL UNIQUE,
     hostname TEXT NOT NULL,
@@ -11,7 +11,7 @@ CREATE TABLE nodes (
     instance_type TEXT NOT NULL
 );
 
-CREATE TABLE jobs (
+CREATE TABLE IF NOT EXISTS jobs (
     id INTEGER PRIMARY KEY,
     pod TEXT NOT NULL UNIQUE,
     node INTEGER NOT NULL,

gantry/__main__.py

@@ -18,7 +18,11 @@
 
 async def init_db(app: web.Application):
     db = await aiosqlite.connect(os.environ["DB_FILE"])
-    await db.execute("PRAGMA foreign_keys = ON;")
+    # create a database with the schema if it doesn't exist
+    # otherwise, this is a noop
+    with open("db/schema.sql") as f:
+        await db.executescript(f.read())
+    await db.commit()
     app["db"] = db
     yield
     await db.close()