Add integration test, for real

.gitignore

@@ -0,0 +1 @@
+test/etc/server/server.properties

Makefile

@@ -1,5 +1,5 @@
 bin/docker_entrypoint: bin
-	cd go/cmd && go build -o $@
+	cd go/cmd && go build -o ../../$@
 
 bin:
 	mkdir bin
@@ -10,5 +10,7 @@ install:
 docker:
 	docker build --no-cache -t docker_entrypoint .
 
-
-.PHONY: install docker
+clean:
+	rm -rf bin \
+	docker rmi docker_entrypoint:latest
+.PHONY: install docker clean

README.md

@@ -1,16 +1,16 @@
 # docker_entrypoint
 Templating engine for docker images
 
-Did you have to spend time in finding out to configure a random docker image you just downloaded from Docker registry?  
+Did you have to spend time in finding out to configure a random docker image you just downloaded from Docker registry?
 
-Wouldn't be nice having the same ENV variable be the same across images without the need of replacing entirelly the whole congiguration file or having to dig `docker inspect` and just run an help command?
+Wouldn't be nice having the same ENV variable be the same across images without the need of replacing entirelly the whole configuration file or having to dig `docker inspect` and just run an help command?
 
-Docker entrypoint manages your configuration file templates rendering them from environemnt variables values. 
+Docker entrypoint manages your configuration file templates rendering them from environemnt variables values.
 
-For example, setting Kafka's broker ID would be as simple as setting an environment variable  
+For example, setting Kafka's broker ID would be as simple as setting an environment variable
 `docker run -d --name kafka -e SERVER_PROPERPERTIES_BROKER_ID = 1 mykafka-image`
 
-and gives users an easy way to access all configuration variables with a `help` command:  
+and gives users an easy way to access all configuration variables with a `help` command:
 `docker run -ti --rm mykafka-image --help
 
 ## Dependencies
@@ -23,20 +23,20 @@ to build the base docker_entrypoing image run
 
 ## Usage
 ### Build a configuration file 
-Create a template configuration file `server.properties.template` like the following  
+Create a template configuration file `server.properties.template` like the following
 ```
 server_address={{ .LISTEN_ADDRESS }}
 server_port={{ .LISTEN_PORT }}
 id={{ .ID }}
 ```
 ### Example dockerfile
-The build your image using docker_entrypoint as first stage of a multi-stage build:  
+The build your image using docker_entrypoint as first stage of a multi-stage build:
 ```
 FROM docker_entrypoint as entrypoint
 FROM alpine #OR YOU FAVOURITE BASE IMAGE
 COPY --from=entrypoint /docker_entrypoint /docker_entrypoint
 RUN ...
-MKDIR ...
+RUN mkdir ...
 ENV SERVER_PROPERTIES_LISTEN_ADDRESS="localhost"
 ENV SERVER_PROPERTIES_LISTEN_PORT=8080
 ENV SERVER_PROPERTIES_ID=1

go/render/templatebuilder.go

@@ -14,12 +14,17 @@ var templateExtension = ".template"
 
 func ExecTemplates(paths ...string) error {
 	for _, path := range paths {
-		fmt.Println(path)
 		if !strings.HasSuffix(path, templateExtension) {
 			return fmt.Errorf("%s is not a .template file", path)
 		}
 		destPath := removeExtension(path)
-		envVars := getEnvironVars(replaceWithUnderscore(destPath))
+
+		filterString := strings.ToUpper(replaceWithUnderscore(destPath))
+		envVars, err := getEnvironVars(filterString)
+		if err != nil {
+			return fmt.Errorf("error getting environment variables for %s: %s", filterString, err)
+		}
+
 		t := template.New(path, destPath, envVars)
 		if err := t.Write(); err != nil {
 			return fmt.Errorf("error rendering template %s: %s", path, err)
@@ -38,14 +43,21 @@ func removeExtension(path string) string {
 	return path[:len(path)-len(templateExtension)]
 }
 
-func getEnvironVars(filterString string) map[string]string {
-	regex, _ := regexp.Compile("^" + filterString + "_")
+func getEnvironVars(filterString string) (map[string]string, error) {
+	prefix := fmt.Sprintf("%s_", filterString)
+	filter := fmt.Sprintf("^%s", prefix)
+	regex, err := regexp.Compile(filter)
+
+	if err != nil {
+		return nil, err
+	}
+
 	vars := make(map[string]string)
 	for _, e := range os.Environ() {
-		pair := strings.SplitAfterN(e, "=", 2)
+		pair := strings.Split(e, "=")
 		if regex.MatchString(pair[0]) {
-			vars[pair[0][len(filterString)+1:len(pair[0])-1]] = pair[1]
+			vars[pair[0][len(prefix):]] = pair[1]
 		}
 	}
-	return vars
+	return vars, nil
 }

go/render/templatebuilder_test.go

@@ -5,10 +5,10 @@ import (
 	"testing"
 )
 
-func TestGetEnvironVars(t*testing.T){
+func TestGetEnvironVars(t *testing.T) {
 	_ = os.Setenv("A_B_C", "1")
-	vars := getEnvironVars("A")
-	if vars["B_C"] != "1"{
+	vars, _ := getEnvironVars("A")
+	if vars["B_C"] != "1" {
 		t.Fatalf("%v", vars)
 	}
 }

go/template/template.go

@@ -16,7 +16,7 @@ func New(templatePath string, outputPath string, vars map[string]string) Templat
 	t := Template{
 		vars,
 		templatePath,
-		trimExtension(outputPath),
+		outputPath,
 	}
 	return t
 }
@@ -44,4 +44,4 @@ func (t *Template) WriteToPath(path string) error {
 func trimExtension(path string) string {
 	var extension = filepath.Ext(path)
 	return path[0 : len(path)-len(extension)]
-}
+}

go/template/template_test.go

@@ -23,10 +23,10 @@ func TestMain(m *testing.M) {
 
 func mockFile(content []byte) (string, error) {
 	if tempFile, err := os.Create(tempDir + "/file.temp"); err == nil {
-		defer func (){ _ = tempFile.Close() }()
+		defer func() { _ = tempFile.Close() }()
 		_, err = tempFile.Write(content)
 		return tempFile.Name(), err
-	}else{
+	} else {
 		return "", err
 	}
 }
@@ -42,7 +42,7 @@ func TestTemplate(t *testing.T) {
 		t.Fatal(err)
 	}
 	vars := map[string]string{
-		testVar : testVal,
+		testVar: testVal,
 	}
 	template := New(templatePath, templatePath, vars)
 	if err := template.WriteToPath(resultPath); err != nil {

test/Dockerfile.test

@@ -1,6 +1,14 @@
 FROM golang:1.13-alpine
 
 WORKDIR /src/
+COPY ./go /src
 
-CMD ls -l /src/
+WORKDIR go
+RUN go build -o /docker_entrypoint github.com/bejelith/docker_entrypoint/cmd
+
+ENV SERVER_PROPERTIES_LISTEN_ADDRESS="localhost"
+ENV SERVER_PROPERTIES_LISTEN_PORT=8080
+ENV SERVER_PROPERTIES_ID=1
+
+WORKDIR /src/
 CMD go test ./... -v

test/docker-compose.yml

@@ -7,7 +7,10 @@ networks:
 services:
   docker_entrypoint_tests:
     build:
-      context: .
-      dockerfile: ./Dockerfile.test
+      context: ..
+      dockerfile: ./test/Dockerfile.test
+  docker_entrypoint_integration:
+    image: test_docker_entrypoint_tests
+    command: ["/docker_entrypoint","-template","/etc/server/server.properties.template","/bin/cat","/etc/server/server.properties"]
     volumes:
-      - $PWD/../go:/src
+      - $PWD/etc/server:/etc/server

test/etc/server/server.properties.template

@@ -0,0 +1,3 @@
+server_address={{ .LISTEN_ADDRESS }}
+server_port={{ .LISTEN_PORT }}
+id={{ .ID }}

vai.sh

@@ -4,4 +4,5 @@ set -euxo pipefail
 
 cd ./test
 
-docker-compose up --build --abort-on-container-exit
+docker-compose up --build --abort-on-container-exit --scale=docker_entrypoint_integration=0
+docker-compose up --build --exit-code-from docker_entrypoint_integration --scale docker_entrypoint_tests=0