matrix-docker-ansible-deploy/roles/custom/matrix-synapse/templates/synapse/customizations/Dockerfile.j2

#jinja2: lstrip_blocks: "True"
FROM {{ matrix_synapse_docker_image }}

{% if matrix_synapse_container_image_customizations_s3_storage_provider_installation_enabled %}
RUN pip install synapse-s3-storage-provider=={{ matrix_synapse_ext_synapse_s3_storage_provider_version }}
{% endif %}

{% if matrix_synapse_container_image_customizations_templates_enabled %}
{#
This ugly script below does quite a lot:
	- installs git and other dependencies temporarily, just so we could do a shallow-clone
	- prepare the SSH config: keyscanning (if enabled), private key (if enabled)
	- performs a git shallow clone with just the branch we need
	- makes sure the files are owned by the user that will actually run the container later
	- removes the `.git` directory to save space, but keeps git revision in `git-revision.txt`, should we need it for debugging
	- finally, verifies that the templates path can indeed be found within the base path (sanity check)
#}
{% set dependencies = ['git', 'ssh', 'openssh-client'] %}
RUN \
	{% if matrix_synapse_container_image_customizations_templates_git_repository_ssh_private_key %}
	echo '{{ matrix_synapse_container_image_customizations_templates_git_repository_ssh_private_key | b64encode }}' | base64 -d > /custom-templates-private-key && \
	chmod 400 /custom-templates-private-key && \
	{% endif %}
	apt-get update && \
	apt-get install --no-install-recommends -y {{ dependencies | join(' ') }} && \
	{% if matrix_synapse_container_image_customizations_templates_git_repository_keyscan_enabled %}
	mkdir ~/.ssh && \
	chmod 700 ~/.ssh && \
	ssh-keyscan -t rsa {{ matrix_synapse_container_image_customizations_templates_git_repository_keyscan_hostname }} >> ~/.ssh/known_hosts && \
	{% endif %}
	{% if matrix_synapse_container_image_customizations_templates_git_repository_ssh_private_key %}GIT_SSH_COMMAND='ssh -i /custom-templates-private-key'{% endif %} git \
		clone \
			--branch={{ matrix_synapse_container_image_customizations_templates_git_repository_branch }} \
			--depth=1 \
			--single-branch \
			--no-tags \
			{{ matrix_synapse_container_image_customizations_templates_git_repository_url }} \
			{{ matrix_synapse_container_image_customizations_templates_in_container_base_path }} && \
	/bin/sh -c 'cd {{ matrix_synapse_container_image_customizations_templates_in_container_base_path }} && git rev-parse HEAD > git-revision.txt' && \
	rm -rf {{ matrix_synapse_container_image_customizations_templates_in_container_base_path }}/.git && \
	chown -R {{ matrix_synapse_uid }}:{{ matrix_synapse_gid }} {{ matrix_synapse_container_image_customizations_templates_in_container_base_path }} && \
	apt-get autoremove -y {{ dependencies | join(' ') }} && \
	{% if matrix_synapse_container_image_customizations_templates_git_repository_ssh_private_key %}
	rm /custom-templates-private-key && \
	{% endif %}
	true

RUN /bin/sh -c 'stat {{ matrix_synapse_container_image_customizations_templates_in_container_base_path }}/{{ matrix_synapse_container_image_customizations_templates_in_container_template_files_relative_path }} || exit 1'
{% endif %}

{{ matrix_synapse_container_image_customizations_dockerfile_body_custom }}