feat(sentry10): Make on-premise work for Sentry 10 (#220)

cron/Dockerfile

@@ -0,0 +1,6 @@
+ARG BASE_IMAGE
+FROM ${BASE_IMAGE}
+RUN apt-get update && apt-get install -y --no-install-recommends cron && \
+    rm -r /var/lib/apt/lists/*
+COPY entrypoint.sh /entrypoint.sh
+ENTRYPOINT ["/entrypoint.sh"]

cron/entrypoint.sh

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+#!/usr/bin/env bash
+
+# Prior art:
+# - https://git.io/fjNOg
+# - https://blog.knoldus.com/running-a-cron-job-in-docker-container/
+
+declare -p | grep -Ev 'BASHOPTS|BASH_VERSINFO|EUID|PPID|SHELLOPTS|UID' > /container.env
+
+{ for cron_job in "$@"; do echo -e "SHELL=/bin/bash
+BASH_ENV=/container.env
+${cron_job} > /proc/1/fd/1 2>/proc/1/fd/2"; done } \
+    | sed --regexp-extended 's/\\(.)/\1/g' \
+    | crontab -
+crontab -l
+exec cron -f -l -L 15