Transitions the Docker image to use s6 and s6-overlay for process supervision instead of supervisord (#8886)

docker/rootfs/usr/local/bin/wait-for-redis.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""
+Simple script which attempts to ping the Redis broker as set in the environment for
+a certain number of times, waiting a little bit in between
+
+"""
+
+import os
+import sys
+import time
+
+import click
+from redis import Redis
+
+
+@click.command(context_settings={"show_default": True})
+@click.option(
+    "--retry-count",
+    default=5,
+    type=int,
+    help="Count of times to retry the Redis connection",
+)
+@click.option(
+    "--retry-sleep",
+    default=5,
+    type=int,
+    help="Seconds to wait between Redis connection retries",
+)
+@click.argument(
+    "redis_url",
+    type=str,
+    envvar="PAPERLESS_REDIS",
+    default="redis://localhost:6379",
+)
+def wait(redis_url: str, retry_count: int, retry_sleep: int) -> None:
+    click.echo("Waiting for Redis...")
+
+    attempt = 0
+    with Redis.from_url(url=redis_url) as client:
+        while attempt < retry_count:
+            try:
+                client.ping()
+                break
+            except Exception as e:
+                click.echo(
+                    f"Redis ping #{attempt} failed.\n"
+                    f"Error: {e!s}.\n"
+                    f"Waiting {retry_sleep}s",
+                )
+                time.sleep(retry_sleep)
+                attempt += 1
+
+    if attempt >= retry_count:
+        click.echo(
+            "Failed to connect to redis using environment variable PAPERLESS_REDIS.",
+        )
+        sys.exit(os.EX_UNAVAILABLE)
+    else:
+        click.echo("Connected to Redis broker.")
+        sys.exit(os.EX_OK)
+
+
+if __name__ == "__main__":
+    wait()