Setup Prelude and Kubernetes binding

This change setups external dhall packages needed by the operator.
The packages are also cached in the operator image to speed up runtime.

Change-Id: Ib6c5774870324224e86b7966f0c720783635df10

build/Dockerfile

@@ -20,6 +20,20 @@ RUN curl -OL https://github.com/dhall-lang/dhall-haskell/releases/download/1.29.
 # Back to the default operator user
 USER 1001
 
+# Install dhall libraries
+RUN git clone --branch v13.0.0 --depth 1 https://github.com/dhall-lang/dhall-lang       /opt/ansible/dhall-lang                    \
+  && git clone --branch v3.0.0 --depth 1 https://github.com/dhall-lang/dhall-kubernetes /opt/ansible/dhall-kubernetes
+ENV DHALL_PRELUDE=/opt/ansible/dhall-lang/Prelude/package.dhall
+ENV DHALL_KUBERNETES=/opt/ansible/dhall-kubernetes/package.dhall
+
+# Copy configuration
+COPY conf/ /opt/ansible/conf/
+
+# Cache dhall objects
+RUN echo 'let Prelude = ~/conf/Prelude.dhall let Kubernetes = ~/conf/Kubernetes.dhall in "OK"' | \
+    env DHALL_PRELUDE=/opt/ansible/dhall-lang/Prelude/package.dhall                              \
+        DHALL_KUBERNETES=/opt/ansible/dhall-kubernetes/package.dhall dhall-to-json
+
 # Copy ansible operator requirements
 COPY watches.yaml ${HOME}/watches.yaml
 

conf/Kubernetes.dhall

@@ -0,0 +1,3 @@
+{- Import the kubernetes types, see the ./Prelude.dhall file for documentation -}
+  env:DHALL_KUBERNETES
+? https://raw.githubusercontent.com/dhall-lang/dhall-kubernetes/3c6d09a9409977cdde58a091d76a6d20509ca4b0/package.dhall sha256:e9c55c7ff71f901314129e7ef100c3af5ec7a918dce25e06d83fa8c5472cb680

conf/Prelude.dhall

@@ -0,0 +1,28 @@
+{- This file provides a central `Prelude` import for the rest of the library to
+   use so that the integrity check only needs to be updated in one place
+   whenever upgrading the interpreter.
+
+   This allows the user to provide their own Prelude import using the
+   `DHALL_PRELUDE` environment variable, like this:
+
+   ```
+   $ export DHALL_PRELUDE='https://prelude.dhall-lang.org/package.dhall sha256:...'
+   ```
+
+   Note that overriding the Prelude in this way only works if this repository
+   is imported locally.  Remote imports do not have access to environment
+   variables and any attempt to import one will fall back to the next available
+   import.  To learn more, read:
+
+   * https://docs.dhall-lang.org/discussions/Safety-guarantees.html#cross-site-scripting-xss
+
+   This file also provides an import without the integrity check as a slower
+   fallback if the user is using a different version of the Dhall interpreter.
+
+   This pattern is documented in the dhall-nethack repo:
+
+   * https://github.com/dhall-lang/dhall-nethack/blob/master/Prelude.dhall
+-}
+  env:DHALL_PRELUDE
+? https://prelude.dhall-lang.org/v13.0.0/package.dhall sha256:4aa8581954f7734d09b7b21fddbf5d8df901a44b54b4ef26ea71db92de0b1a12
+? https://prelude.dhall-lang.org/v13.0.0/package.dhall