hack: verify builds are installable (kubernetes-sigs#262)

This script tests if a build is installable (as documented in the readme)
from its tarball+yaml file.

I felt like adding this as extra confidence on all the refactoring we're doing,
and I know we have integration tests that cover this. Since installation is
almost like our API, I thought it would be good to test.

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

.travis.yml

@@ -16,6 +16,7 @@ script:
 - hack/run-lint.sh
 - go test -v -short -coverprofile=coverage.txt -covermode=atomic ./...
 - hack/make-all.sh
+- hack/verify-installation.sh
 - hack/ensure-kubectl-installed.sh
 - hack/run-integration-tests.sh
 - hack/verify-receipts-upgrade-migration.sh

hack/make-release-artifacts.sh

@@ -21,7 +21,7 @@ cd "${SCRIPTDIR}/.."
 
 bin_dir="out/bin"
 if [[ ! -d "${bin_dir}" ]]; then
-    echo >&2 "Binaries are not built (${bin_dir}), run build-binaries.sh"
+    echo >&2 "Binaries are not built (${bin_dir}), run hack/make-binaries.sh"
     exit 1
 fi
 

hack/verify-installation.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+
+# Copyright 2019 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script verifies that a krew build can be installed to a system using
+# itself as the documented installation method.
+
+set -euo pipefail
+
+[[ -n "${DEBUG:-}" ]] && set -x
+
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+build_dir="${SCRIPTDIR}/../out"
+goos="$(go env GOOS)"
+goarch="$(go env GOARCH)"
+
+krew_manifest="${build_dir}/krew.yaml"
+if [[ ! -f "${krew_manifest}" ]]; then
+    echo >&2 "Could not find manifest ${krew_manifest}.";
+    echo >&2 "Did you run hack/make-all.sh?";
+    exit 1
+fi
+
+krew_archive="${build_dir}/krew.tar.gz"
+if [[ ! -f "${krew_archive}" ]]; then
+    echo >&2 "Could not find archive ${krew_archive}.";
+    echo >&2 "Did you run hack/make-all.sh?";
+    exit 1
+fi
+
+temp_dir="$(mktemp -d)"
+trap 'rm -rf -- "${temp_dir}"' EXIT
+echo >&2 "Extracting krew from tarball."
+tar zxf "${krew_archive}" -C "${temp_dir}"
+krew_binary="${temp_dir}/krew-${goos}_${goarch}"
+
+krew_root="$(mktemp -d)"
+trap 'rm -rf -- "${krew_root}"' EXIT
+system_path="/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin"
+
+echo >&2 "Installing the krew build to a temporary directory."
+env -i KREW_ROOT="${krew_root}" \
+    "${krew_binary}" install \
+        --manifest="${krew_manifest}" \
+        --archive "${krew_archive}"
+
+echo >&2 "Verifying krew installation (symlink)."
+env -i PATH="${krew_root}/bin:${system_path}" /bin/bash -c \
+    "which kubectl-krew 1>/dev/null"