add dockerfile to build container

Dockerfile

@@ -0,0 +1,15 @@
+# Copyright (c) 2018 Anton Semjonov
+# Licensed under the MIT License
+
+FROM python:alpine
+
+# default cron interval
+ENV MINUTES=15
+
+# copy init script which execs crond
+COPY assets/container/init.sh /init.sh
+ENTRYPOINT ["/bin/ash", "/init.sh", "/usr/bin/imapfetch.py"]
+CMD ["/config"]
+
+# copy imapfetch script
+COPY imapfetch/imapfetch.py /usr/bin/imapfetch.py

README.md

@@ -108,8 +108,6 @@ decently fast for example.
 Make sure you run a decently modern Python 3 (anything newer than `3.5` _should_ work, development
 was done on `3.7`).
 
-TODO: `deb`, `rpm`
-
 ### PIP
 
 Install the package via `pip` by running:
@@ -126,6 +124,28 @@ Or use the `PKGBUILD` in `master` to build `imapfetch-git` locally:
 
     makepkg -i
 
+### RPM, DEB, APK
+
+Other packages can be built with [ansemjo/fpm](https://hub.docker.com/r/ansemjo/fpm/) using the
+`makefile` or downloaded from the [releases page](https://github.com/ansemjo/imapfetch/releases).
+They can then be installed locally with `yum`/`dnf`/`dpkg` etc.
+
+    make packages
+
+## CONTAINER
+
+The script can also be scheduled to run regularly with cron inside a container with
+[ansemjo/imapfetch](https://hub.docker.com/r/ansemjo/imapfetch/). Download or build the image with
+the provided `Dockerfile`, then run the container with `docker` or `podman`:
+
+    podman run -d \
+      -v ~/.config/imapfetch.cfg:/config \
+      -v ~/Documents/Email-Archive:/archive \
+      ansemjo/imapfetch
+
+Mount your configuration file and the root directory of your configured archives in the container as
+seen above.
+
 ## LICENSE
 
 The script is licensed under the [MIT License](LICENSE).

assets/container/init.sh

@@ -0,0 +1,24 @@
+#!/bin/ash
+
+# Copyright (c) 2018 Anton Semjonov
+# Licensed under the MIT License
+
+# command is given as parameter
+export COMMAND="${*:?command required}"
+
+# assemble cron schedule from env
+# either use '-e MINUTES=n' to run test every n minutes
+# or define the complete schedule part with '-e SCHEDULE=...'
+export SCHEDULE="${SCHEDULE:-"*/$MINUTES * * * *"}"
+
+# install crontab
+echo "$SCHEDULE $COMMAND" | crontab -
+
+# run command once before schedule
+${SHELL:-sh} -c "$COMMAND" || {
+  echo "command error. exiting."
+  exit 1
+}
+
+# exec crontab in foreground
+exec crond -f

makefile

@@ -42,4 +42,17 @@ package-% : install
 		--maintainer $(PKGAUTHOR) --license $(PKGLICENSE) --url $(PKGURL)
 
 # build all package formats with fpm
+.PHONY: packages
 packages : $(addprefix package-,$(PKGFORMATS))
+
+# container runtime
+CONTAINER = podman
+IMAGENAME = ansemjo/$(PKGNAME)
+
+# build and tag container
+.PHONY: container
+container:
+	$(CONTAINER) build \
+		-t $(IMAGENAME):latest \
+		-t $(IMAGENAME):$(PKGVERSION) \
+		.