feat(ci): release docker image for PRs and master

Signed-off-by: Lorenzo Fontana <[email protected]>

.travis.yml

@@ -0,0 +1,9 @@
+language: go
+go:
+- 1.11.4
+services:
+- docker
+script:
+- make _output/bin/kubectl-trace
+after_success:
+- ./hack/release-image.sh

Makefile

@@ -46,3 +46,4 @@ image/push:
 image/latest:
 	$(DOCKER) tag $(IMAGE_BPFTRACE_COMMIT) $(IMAGE_BPFTRACE_LATEST)
 	$(DOCKER) push $(IMAGE_BPFTRACE_LATEST)
+

hack/release-image.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -xeo pipefail
+
+# Script that builds the bpftrace image and releases
+# it to quay only if the request is coming from the main repo.
+
+make=$(command -v make)
+docker=$(command -v docker)
+
+$make image/build
+
+if [[ ! -z "$QUAY_TOKEN" ]]; then
+  $docker login -u="fntlnz+travisci" -p="$QUAY_TOKEN" quay.io
+  $make image/push
+
+  if [[ "TRAVIS_BRANCH" == "master" ]]; then
+    $make image/latest
+  fi
+fi
+