Docker build for ARM (Raspberry Pi) (#2436)

* Docker build for ARM (Raspberry Pi)

Inspired by https://github.com/stas-demydiuk/domoticz-docker

* Execution rights

* Readme typo

* Move QEMU higher up

* Change tar command

* Try to fix COPY error

* Fix path bug

3 files changed, 61 insertions, 2 deletions

diff --git a/Docker/Dockerfile-QEMU-ARM b/Docker/Dockerfile-QEMU-ARM
new file mode 100644
index 000000000..889be2cb8
--- /dev/null
+++ b/Docker/Dockerfile-QEMU-ARM
@@ -0,0 +1,46 @@
+# Only relevant for Docker Hub or QEMU multi-architecture builds.
+# Prefer the normal `Dockerfile` if you are building manually on the targeted architecture.
+
+FROM arm32v7/ubuntu:19.04
+
+# Requires ./hooks/*
+COPY ./Docker/qemu-* /usr/bin/
+
+ENV TZ UTC
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
+RUN apt update && \
+	apt install --no-install-recommends -y \
+	ca-certificates cron \
+	apache2 libapache2-mod-php \
+	php-curl php-intl php-mbstring php-xml php-zip \
+	php-sqlite3 php-mysql php-pgsql && \
+	rm -rf /var/lib/apt/lists/*
+
+RUN mkdir -p /var/www/FreshRSS/ /run/apache2/
+WORKDIR /var/www/FreshRSS
+
+COPY . /var/www/FreshRSS
+COPY ./Docker/*.Apache.conf /etc/apache2/sites-available/
+
+RUN a2dismod -f alias autoindex negotiation status && \
+	a2enmod deflate expires headers mime setenvif && \
+	a2disconf '*' && \
+	a2dissite '*' && \
+	a2ensite 'FreshRSS*'
+
+RUN sed -r -i "/^\s*(CustomLog|ErrorLog|Listen) /s/^/#/" /etc/apache2/apache2.conf && \
+	sed -r -i "/^\s*Listen /s/^/#/" /etc/apache2/ports.conf && \
+	touch /var/www/FreshRSS/Docker/env.txt && \
+	echo "17,47 * * * * . /var/www/FreshRSS/Docker/env.txt; \
+		su www-data -s /bin/sh -c 'php /var/www/FreshRSS/app/actualize_script.php' \
+		2>> /proc/1/fd/2 > /tmp/FreshRSS.log" | crontab -
+
+ENV COPY_SYSLOG_TO_STDERR On
+ENV CRON_MIN ''
+ENTRYPOINT ["./Docker/entrypoint.sh"]
+
+EXPOSE 80
+CMD ([ -z "$CRON_MIN" ] || cron) && \
+	. /etc/apache2/envvars && \
+	exec apache2 -D FOREGROUND
diff --git a/Docker/README.md b/Docker/README.md
index cdb6a0a4e..c2db38fb5 100644
--- a/Docker/README.md
+++ b/Docker/README.md
@@ -37,6 +37,7 @@ sudo docker run -d --restart unless-stopped --log-opt max-size=10m \
   -p 80:80 \
   -p 443:443 \
   --name traefik traefik --docker \
+  --loglevel=info \
   --entryPoints='Name:http Address::80 Compress:true Redirect.EntryPoint:https' \
   --entryPoints='Name:https Address::443 Compress:true TLS TLS.MinVersion:VersionTLS12 TLS.SniStrict:true TLS.CipherSuites:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA' \
   --defaultentrypoints=http,https --keeptrailingslash=true \
@@ -51,7 +52,7 @@ See [more information about Docker and Let’s Encrypt in Træfik](https://docs.
 Example using the built-in refresh cron job (see further below for alternatives).
 You must first chose a domain (DNS) or sub-domain, e.g. `freshrss.example.net`.
 
-> **N.B.:** For platforms other than x64 (Intel, AMD), such as ARM (e.g. Raspberry Pi), see the section *Build Docker image* further below.
+> **N.B.:** Default images are for x64 (Intel, AMD) platforms. For ARM (e.g. Raspberry Pi), use the `*-arm` tags. For other platforms, see the section *Build Docker image* further below.
 
 ```sh
 sudo docker volume create freshrss-data
@@ -137,7 +138,7 @@ The tags correspond to FreshRSS branches and versions:
 * `:x.y.z` are specific FreshRSS releases
 
 ### Linux: Ubuntu vs. Alpine
-Our default image is based on [Ubuntu](https://www.ubuntu.com/server). We offer an alternative based on [Alpine](https://alpinelinux.org/) (with the `-alpine` tag suffix).
+Our default image is based on [Ubuntu](https://www.ubuntu.com/server). We offer an alternative based on [Alpine](https://alpinelinux.org/) (with the `*-alpine` tag suffix).
 In [our tests](https://github.com/FreshRSS/FreshRSS/pull/2205), Ubuntu is ~3 times faster,
 while Alpine is ~2.5 times [smaller on disk](https://hub.docker.com/r/freshrss/freshrss/tags) (and much faster to build).
 
diff --git a/Docker/hooks/pre_build b/Docker/hooks/pre_build
new file mode 100755
index 000000000..f6c8211c0
--- /dev/null
+++ b/Docker/hooks/pre_build
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+if [[ "$DOCKERFILE_PATH" == *-ARM ]];
+then
+	# https://github.com/balena-io/qemu
+	# Download a local copy of QEMU on Docker Hub build machine
+	curl -LSs 'https://github.com/balena-io/qemu/releases/download/v3.0.0%2Bresin/qemu-3.0.0+resin-arm.tar.gz' | tar -xzv --strip-components=1 --wildcards '*/qemu-*'
+
+	# https://github.com/multiarch/qemu-user-static
+	# Register qemu-*-static for all supported processors except the current one, but also remove all registered binfmt_misc before
+	docker run --rm --privileged multiarch/qemu-user-static:register --reset
+fi