build: docker images for latest release and main branch (#2116)

This PR adds docker image building to the github actions workflow.

Two images are built:
- unstable: This is built from the current branch
- latest: This is built from the version of rdflib in
  `docker/latest/requirements.txt`, but as this will be updated by
  dependabot it will essentially always be the latest version.

The resulting image references are:

- `ghcr.io/rdflib/rdflib:unstable`
- `ghcr.io/rdflib/rdflib:latest` with an alias
  `ghcr.io/rdflib/rdflib:${rdflib_version}`, e.g.
  `ghcr.io/rdflib/rdflib:6.2.0`.

As dependabot is conifgured for both pyton and docker dependencies, any
change/update to dependencies will result in a new image being built.

To avoid spurious changes in image digests the existing image is used as
the cache source, so if the requirements.txt and Dockerfile for
`ghcr.io/rdflib/rdflib:latest` has not changed then a new image should
not be published for it even if the build runs.

I have tested this in my forked repo, but there may be some kinks to
still work out.

5 files changed, 66 insertions, 0 deletions

diff --git a/docker/latest/Dockerfile b/docker/latest/Dockerfile
new file mode 100644
index 00000000..f5ecc9f8
--- /dev/null
+++ b/docker/latest/Dockerfile
@@ -0,0 +1,9 @@
+FROM docker.io/library/python:3.10-slim@sha256:c212a18a48efd4de1d6455f197538563d9cc312775761f14c50866c9a7eabd0e
+
+COPY docker/latest/requirements.txt /var/tmp/build/
+
+RUN \
+    pip install --no-deps -r /var/tmp/build/requirements.txt && \
+    rdfpipe --version
+
+ENTRYPOINT [ ]
diff --git a/docker/latest/requirements.in b/docker/latest/requirements.in
new file mode 100644
index 00000000..c704360a
--- /dev/null
+++ b/docker/latest/requirements.in
@@ -0,0 +1,2 @@
+rdflib==6.2.0
+html5lib
diff --git a/docker/latest/requirements.txt b/docker/latest/requirements.txt
new file mode 100644
index 00000000..541b7580
--- /dev/null
+++ b/docker/latest/requirements.txt
@@ -0,0 +1,22 @@
+#
+# This file is autogenerated by pip-compile with python 3.10
+# To update, run:
+#
+#    pip-compile docker/latest/requirements.in
+#
+html5lib==1.1
+    # via -r docker/latest/requirements.in
+isodate==0.6.1
+    # via rdflib
+pyparsing==3.0.9
+    # via rdflib
+rdflib==6.2.0
+    # via -r docker/latest/requirements.in
+six==1.16.0
+    # via html5lib
+webencodings==0.5.1
+    # via html5lib
+
+# The following packages are considered to be unsafe in a requirements file:
+# setuptools
+
diff --git a/docker/unstable/Dockerfile b/docker/unstable/Dockerfile
new file mode 100644
index 00000000..2bba3f6b
--- /dev/null
+++ b/docker/unstable/Dockerfile
@@ -0,0 +1,14 @@
+FROM docker.io/library/python:3.10-slim@sha256:c212a18a48efd4de1d6455f197538563d9cc312775761f14c50866c9a7eabd0e
+
+COPY docker/unstable/requirements.txt /var/tmp/build/
+
+RUN \
+    pip install -r /var/tmp/build/requirements.txt
+
+COPY dist/*.whl /var/tmp/build/
+
+RUN \
+    pip install --no-deps /var/tmp/build/*.whl && \
+    rdfpipe --version
+
+ENTRYPOINT [ ]
diff --git a/docker/unstable/requirements.txt b/docker/unstable/requirements.txt
new file mode 100644
index 00000000..529eead7
--- /dev/null
+++ b/docker/unstable/requirements.txt
@@ -0,0 +1,19 @@
+#
+# This file is autogenerated by pip-compile with python 3.10
+# To update, run:
+#
+#    pip-compile --output-file=docker/unstable/requirements.txt requirements.txt
+#
+html5lib==1.1
+    # via -r requirements.txt
+isodate==0.6.1
+    # via -r requirements.txt
+pyparsing==3.0.9
+    # via -r requirements.txt
+six==1.16.0
+    # via
+    #   html5lib
+    #   isodate
+webencodings==0.5.1
+    # via html5lib
+