chore: enable wait for it via env var (#31)

* chore: add wait-for-it to dockerfile

* feat: add and document wait-for-it behaviour

* chore: fix use of wait-for-it

* chore: raise timeout to 120 seconds

* chore: add prints to entrypoint

Dockerfile

@@ -5,12 +5,13 @@ WORKDIR /code
 ENV PYTHONPATH "${PYTHONPATH}:/code"
 ENV PORT=8000
 ENV GET_POETRY https://raw.github.com/python-poetry/poetry/master/get-poetry.py
+ENV WAIT_FOR_IT_URL https://raw.github.com/vishnubob/wait-for-it/master/wait-for-it.sh
 
 EXPOSE ${PORT}
 
 RUN apk update && \
     apk upgrade && \
-    apk add curl gcc musl-dev build-base
+    apk add curl gcc musl-dev build-base bash
 
 # Install Poetry
 RUN curl -sSL ${GET_POETRY} | POETRY_HOME=/opt/poetry python && \
@@ -23,6 +24,10 @@ COPY ./pyproject.toml ./poetry.lock* /code/
 
 RUN poetry install --no-root --no-dev
 
+# Download wait-for-it.sh
+ADD ${WAIT_FOR_IT_URL} /
+RUN chmod +x /wait-for-it.sh
+
 COPY ./scripts /code/scripts
 COPY ./alembic.ini .
 COPY ./alembic ./alembic

README.md

@@ -66,6 +66,7 @@ You need to supply the following environment variables (required ones are marked
 - 🚩 **MYSQL_PASSWORD** (`str`): mysql password.
 - 🚩 **MYSQL_PORT** (`str`): mysql port.
 - 🚩 **MYSQL_USER** (`str`): mysql user.
+- **WAIT_FOR_IT_ADDRESS** (`str`): if is set, it will wait for the database to be ready for max 120 seconds. Must be set to `$MYSQL_HOST:$MYSQL_PORT`. This switch should not be used in Kubernetes deployments, as initContainers are designed to cover this exact use case.
 
 ### Other
 

entrypoint.sh

@@ -1,8 +1,18 @@
 #! /usr/bin/env sh
 set -e
 
+if [[ -z "${WAIT_FOR_IT_ADDRESS}" ]]; then
+  echo "Skipping wait-for-it ($$WAIT_FOR_IT_ADDRESS is not defined)"
+else
+  echo "running wait-for-it.sh -t 120 ${WAIT_FOR_IT_ADDRESS}"
+  /wait-for-it.sh -t 120 "${WAIT_FOR_IT_ADDRESS}"
+fi
+
+echo "Ensuring database existence"
 python ./scripts/ensure-database.py
 
+echo "Upgrading database"
 alembic upgrade head
 
+echo "Launching uvicorn server"
 exec uvicorn app.main:app --host 0.0.0.0 --port ${PORT}