Add Dockerfile.install for testing plugin installation locally (#227)

Author: mumoshu

Makefile

@@ -1,6 +1,8 @@
 HELM_HOME ?= $(shell helm home)
 VERSION := $(shell sed -n -e 's/version:[ "]*\([^"]*\).*/\1/p' plugin.yaml)
 
+HELM_3_PLUGINS := $(shell bash -c 'eval $$(helm env); echo $$HELM_PLUGINS')
+
 PKG:= github.com/databus23/helm-diff
 LDFLAGS := -X $(PKG)/cmd.Version=$(VERSION)
 
@@ -19,6 +21,12 @@ install: build
 	cp bin/diff $(HELM_HOME)/plugins/helm-diff/bin
 	cp plugin.yaml $(HELM_HOME)/plugins/helm-diff/
 
+.PHONY: install/helm3
+install/helm3:
+	mkdir -p $(HELM_3_PLUGINS)/helm-diff/bin
+	cp bin/diff $(HELM_3_PLUGINS)/helm-diff/bin
+	cp plugin.yaml $(HELM_3_PLUGINS)/helm-diff/
+
 .PHONY: lint
 lint:
 	scripts/update-gofmt.sh
@@ -70,3 +78,9 @@ ifndef GITHUB_TOKEN
 	$(error GITHUB_TOKEN is undefined)
 endif
 	scripts/release.sh v$(VERSION) master
+
+# Test for the plugin installation with `helm plugin install -v THIS_BRANCH` works
+# Useful for verifying modified `install-binary.sh` still works against various environments
+.PHONY: test-plugin-installation
+test-plugin-installation:
+	docker build -f testdata/Dockerfile.install .

testdata/Dockerfile.install

@@ -0,0 +1,36 @@
+FROM alpine/helm:2.16.9
+
+ADD . /workspace
+
+WORKDIR /workspace
+
+RUN helm init -c
+RUN helm plugin install .
+RUN helm version -c
+
+FROM alpine/helm:3.2.4
+
+ADD . /workspace
+
+WORKDIR /workspace
+
+RUN helm plugin install .
+RUN helm version -c
+
+FROM ubuntu:focal
+
+ADD . /workspace
+
+WORKDIR /workspace
+
+# See "From Apt (Debian/Ubuntu)" at https://helm.sh/docs/intro/install/
+RUN apt-get update && \
+    apt-get install curl && \
+    curl https://helm.baltorepo.com/organization/signing.asc | sudo apt-key add - && \
+    apt-get install apt-transport-https --yes && \
+    echo "deb https://baltocdn.com/helm/stable/debian/ all main" | tee /etc/apt/sources.list.d/helm-stable-debian.list && \
+    apt-get update && \
+    apt-get install helm
+
+RUN helm plugin install .
+RUN helm version -c