add dockerfile. add make targets. add sections to the readme.

Author: syakovlevdalet

Dockerfile

@@ -0,0 +1,38 @@
+FROM golang:1.16.3-alpine AS builder
+
+RUN apk add --update --no-cache make
+ENV PROJECT_NAME=tfdocs-format-template
+ENV SOURCE_DIR=/go/src/${PROJECT_NAME}
+# replace tdocs-format-template with actual formatter plugin name.
+WORKDIR ${SOURCE_DIR}
+
+COPY go.mod .
+COPY go.sum .
+RUN go mod download
+
+COPY . .
+RUN make build
+
+################
+
+FROM quay.io/terraform-docs/terraform-docs:latest
+# added because custom plugin should be installed into the $HOME
+ENV PROJECT_NAME=tfdocs-format-template
+ENV BUILD_CONTAINER_WD=/go/src/${PROJECT_NAME}
+ENV USER=docker
+ENV UID=12345
+ENV GID=23456
+# creating user in docker container
+RUN adduser \
+    --disabled-password \
+    --gecos "" \
+    --home "$(pwd)" \
+    --ingroup "root" \
+    --uid "$UID" \
+    "$USER"
+# after this, all commands will be executed from this user
+USER docker
+
+COPY --from=builder ${BUILD_CONTAINER_WD}/bin/linux-amd64/${PROJECT_NAME} $HOME/.tfdocs.d/plugins/${PROJECT_NAME}
+
+CMD ["/bin/sh","-c","terraform-docs","$@"]

Makefile

@@ -6,6 +6,13 @@ PLUGIN_FOLDER ?= ~/.tfdocs.d/plugins
 GOOS   ?= $(shell go env GOOS)
 GOARCH ?= $(shell go env GOARCH)
 
+CUR_VERSION ?=v1.0.0
+DEFAULT_TAG  ?= $(shell echo "$(CUR_VERSION)" | tr -d 'v')
+DOCKER_REGISTRY :=quay.io
+PROJECT_OWNER := terraform-focs
+DOCKER_IMAGE := $(DOCKER_REGISTRY)/$(PROJECT_OWNER)/$(BUILD_NAME)
+DOCKER_TAG   ?= $(DEFAULT_TAG)
+
 all: clean verify build
 
 clean:
@@ -21,4 +28,10 @@ install: build
 	mkdir -p $(PLUGIN_FOLDER)
 	mv ./$(BUILD_DIR)/$(GOOS)-$(GOARCH)/$(BUILD_NAME) $(PLUGIN_FOLDER)
 
+docker: ## Build Docker image
+	docker build --pull --tag $(DOCKER_IMAGE):$(DOCKER_TAG) --file Dockerfile .
+
+push: ## Push Docker image
+	docker push $(DOCKER_IMAGE):$(DOCKER_TAG)
+
 .PHONY: all clean verify build install help

README.md

@@ -54,6 +54,58 @@ Note that the plugin has to be built for target OS and architecture (`make build
 and `make install` do that,) but if you want to redistribute the plugin for other
 people to use you have to cross-compile it (for example you can use [gox].)
 
+## Docker
+
+If you don't want cross-compile your plugin, you can pack it to the docker image. 
+So the only dependency needed the user/or a server machine is `docker`.
+
+### Building and publishing docker image
+
+```bash
+make docker
+```
+
+Before you will build your docker image you have to replace very few things in the `Makefile` and the `Dockerfile`.
+
+Things to replace:
+
+`Makefile`:
+- DOCKER_REGISTRY (could be any docker registry)
+- PROJECT_OWNER (how the the place file in your registry. In our company it's something like `devops/tools`)
+- BUILD_NAME (your project name should follow the patter `tfdocs-format-<uniqueName>` )
+
+`Dockerfile`:
+- all **PROJECT_NAME** entries should be replaced with your project name( and it should follow the pattern `tfdocs-format-<uniqueName>`)
+
+After all changes and `make docker` successful execution, you can push your new perfect image to the registry by:
+```bash
+make push
+```
+
+### Using docker image with your custom plugin
+
+I'm a little lazy, and I made a simple sh script for easy usage of docker image with terraform-docs and the custom plugin:
+
+```shell
+#!/bin/bash
+
+img=<link to the docker image with terraform-docs and custom plugin>
+
+dir=$1
+out_file=$2
+
+function printMarkdownTo() {
+  pushd $1
+    (docker run --rm -v `pwd`:`pwd` -w `pwd` $img .) > $2
+  popd
+}
+
+printMarkdownTo ${dir} ${out_file}
+
+```
+
+## Links
+
 [terraform-docs]: https://github.com/terraform-docs/terraform-docs
 [plugin SDK]: https://github.com/terraform-docs/plugin-sdk
 [Go]: https://golang.org/