Add license checker

Signed-off-by: NRenaud Gaubert <rgaubert@nvidia.com>

.gitlab-ci.yml

+services:
+  - docker:stable-dind
+
+variables:
+  LICENSE_TAG: $CI_REGISTRY_IMAGE:license
+
+stages:
+  - build
+  - unit
+
+license-builder:
+  image: docker:stable
+  stage: build
+  only:
+#    changes:
+#     - license/Dockerfile
+  script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build -t $LICENSE_TAG ./license
+    - docker push $LICENSE_TAG
+
+license:
+  stage: unit
+  image:
+    name: $LICENSE_TAG
+  script:
+    - ./license/check.sh

license/Dockerfile

+FROM debian:buster-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        ruby \
+        ruby-dev \
+        bundler \
+        cmake \
+        pkg-config \
+        git \
+        build-essential \
+        libssl-dev
+
+RUN gem install licensee
+
+CMD ["/bin/bash"]

license/check.sh

+#! /bin/bash
+
+set -ex
+
+
+find . \( -path ./.git -o -path ./license \)  -prune -o -print -type f | \
+	grep -i -E "license|copying" > /tmp/LICENSES.list
+
+for path in `cat /tmp/LICENSES.list`; do
+	# Print the license for logging purposes
+	licensee detect ${path} | tee -a /tmp/LICENSE.full
+
+	# Ensure the format is of the form "${path} ${license}"
+	license=$(licensee detect ${path} | \
+		grep '^License:' | tr -s ' ' | awk '{print $2}')
+	confidence=$(licensee detect ${path} | \
+		tr -s ' ' | grep -E '^ Confidence:' | awk '{print $2}')
+
+	echo "Inspecting License ${license} (${confidence}) at ${path}" | tee -a /tmp/LICENSE.result
+	if ! grep -Fxq "${license}" ./license/whitelist.txt; then
+		echo "Found unexpected license at ${path}"
+		exit 1
+	fi
+done
+
+cat /tmp/LICENSE.result

license/whitelist.txt

+Apache-2.0
+BSD-3-Clause
+MIT