recreate

.gitignore

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+.idea

LICENSE

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+MIT License
+
+Copyright (c) 2021 lobz1g
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+[![Go Report Card](https://goreportcard.com/badge/github.com/lobz1g/docen)](https://goreportcard.com/report/github.com/lobz1g/docen)
+
+# Docen
+
+Simple utility for generating Dockerfile for golang projects.
+
+## Installation
+
+```shell
+go get github.com/lobz1g/docen
+```
+
+## Usage
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/lobz1g/docen"
+)
+
+func main() {
+	err := docen.New().
+		SetGoVersion("1.14.9").
+		SetPort("3000").
+		SetTimezone("Europe/Moscow").
+		SetTestMode(true).
+		SetAdditionalFolder("my-folder/some-files").
+		SetAdditionalFile("another-folder/some-files/file").
+		GenerateDockerfile()
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+Dockerfile will be created in the root dir of the project.
+
+```dockerfile
+FROM golang:1.14.9-alpine as builder
+RUN apk update && apk add --no-cache git ca-certificates tzdata && update-ca-certificates
+RUN adduser -D -g '' appuser
+RUN mkdir -p /docen
+RUN mkdir -p /docen/my-folder/some-files
+RUN mkdir -p /docen/another-folder/some-files
+COPY . /docen
+WORKDIR /docen
+RUN CGO_ENABLED=0 go test ./...
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build  -ldflags="-w -s" -o /docen
+FROM scratch
+COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=builder /etc/passwd /etc/passwd
+ENV TZ=Europe/Moscow
+COPY --from=builder /docen /docen
+COPY --from=builder /docen/my-folder/some-files /docen/my-folder/some-files
+COPY --from=builder /docen/another-folder/some-files /docen/another-folder/some-files
+COPY --from=builder /docen/another-folder/some-files/file /docen/another-folder/some-files/file
+USER appuser
+EXPOSE 3000
+ENTRYPOINT ["/docen"]
+```
+
+## Options
+
+All methods are optional. That means there are default values for success creating Dockerfile without any settings.
+
+Just use below code for generating Dockerfile with default values:
+
+```go
+err := docen.New().GenerateDockerfile()
+if err != nil {
+    log.Fatal(err)
+}
+```
+
+### Image
+
+By default, the image name is `golang` and the tag is `{your_golang_version}-aplpine`. If the `runtime.Version` method
+returns wrong information about your golang version it will be just `alpine` image tag. You can set the version by
+method `SetGoVersion` without any settings.
+
+### Expose port
+
+By default, Dockerfile will be without the expose port field. You can set the port by method `SetPort`. The argument can
+be a single value of port, for example `3000`, or a range of values, for example `3000-4000`.
+
+### Timezone
+
+By default, Dockerfile will be without the timezone env field. You can set the timezone by method `SetTimezone`.
+
+### Testing
+
+The image is built without testing, but you can test the app before build. Use the method `SetTestMode` for it.
+
+### Additional folders to image
+
+Such folders as `assets`, `config`, `static` and `templates` are added to the image. You can add additional folders by
+method `SetAdditionalFolder`.
+
+### Additional files to image
+
+You can set additional files which should be added to the image. Use the `SetAdditionalFile` method for it. It also adds
+additional folders for these files.

docen.go

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+package docen
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"io/fs"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+)
+
+const (
+	defaultAppName    = "app"
+	defaultTagVersion = "alpine"
+)
+
+var (
+	goModFile         = "go.mod"
+	vendorFolderName  = "vendor"
+	additionalFolders = map[string]bool{
+		"static":    true,
+		"assets":    true,
+		"templates": true,
+		"config":    true,
+	}
+
+	// readDir used for unit testing
+	readDir = ioutil.ReadDir
+	// runVer used for unit testing
+	runVer = runtime.Version
+	// openFile used for unit testing
+	openFile = os.Open
+)
+
+type (
+	docener interface {
+		New() *Docen
+	}
+
+	additionalInfo map[string]bool
+
+	Docen struct {
+		timezone        string
+		version         string
+		port            string
+		additionFolders additionalInfo
+		additionFiles   additionalInfo
+		isTestMode      bool
+	}
+)
+
+// New method creates new instance of generator.
+// By default, the golang version is taken from runtime.Version
+// By default, additional folders are `static`, `templates`, `config` and `assets`.
+func New() *Docen {
+	d := &Docen{
+		version:         getVersion(),
+		additionFolders: getAdditionalFolders(),
+		additionFiles:   newAdditionalInfo(),
+	}
+	return d
+}
+
+// SetGoVersion method allows you to set a specific version of golang.
+func (d *Docen) SetGoVersion(version string) *Docen {
+	d.version = fmt.Sprintf("%s-%s", version, defaultTagVersion)
+	return d
+}
+
+// SetPort method allows you to set an exposed port. It can be as single port as a range of ports.
+func (d *Docen) SetPort(port string) *Docen {
+	d.port = port
+	return d
+}
+
+// SetTimezone method allows you to set a specific timezone.
+func (d *Docen) SetTimezone(timezone string) *Docen {
+	d.timezone = timezone
+	return d
+}
+
+// SetAdditionalFolder method allows you to set additional folders which will be added to a container.
+func (d *Docen) SetAdditionalFolder(path string) *Docen {
+	d.additionFolders.set(path)
+	return d
+}
+
+// SetAdditionalFolder method allows you to set additional files which will be added to a container.
+func (d *Docen) SetAdditionalFile(path string) *Docen {
+	d.additionFiles.set(path)
+	d.SetAdditionalFolder(filepath.Dir(path))
+	return d
+}
+
+// SetTestMode method allows you to enable testing before starting to build the app.
+func (d *Docen) SetTestMode(mode bool) *Docen {
+	d.isTestMode = mode
+	return d
+}
+
+// GenerateDockerfile method creates Dockerfile file.
+// If vendor mode is enabled then building will be with `-mod=vendor` tag.
+func (d *Docen) GenerateDockerfile() error {
+	packageName := getPackageName()
+
+	var data strings.Builder
+	data.WriteString(fmt.Sprintf("FROM golang:%s as builder\n", d.version))
+	data.WriteString("RUN apk update && apk add --no-cache git ca-certificates tzdata && update-ca-certificates\n")
+	data.WriteString("RUN adduser -D -g '' appuser\n")
+
+	data.WriteString(fmt.Sprintf("RUN mkdir -p /%s\n", packageName))
+	for v := range d.additionFolders {
+		data.WriteString(fmt.Sprintf("RUN mkdir -p /%s/%s\n", packageName, v))
+	}
+	data.WriteString(fmt.Sprintf("COPY . /%s\n", packageName))
+	data.WriteString(fmt.Sprintf("WORKDIR /%s\n", packageName))
+	if d.isTestMode {
+		data.WriteString("RUN CGO_ENABLED=0 go test ./...\n")
+	}
+
+	var vendorTag string
+	if isVendorMode() {
+		vendorTag = "-mod=vendor"
+	}
+	data.WriteString(
+		fmt.Sprintf(
+			"RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build %s -ldflags=\"-w -s\" -o /%s\n",
+			vendorTag, packageName,
+		),
+	)
+
+	data.WriteString("FROM scratch\n")
+	data.WriteString("COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo\n")
+	data.WriteString("COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/\n")
+	data.WriteString("COPY --from=builder /etc/passwd /etc/passwd\n")
+	if d.timezone != "" {
+		data.WriteString(fmt.Sprintf("ENV TZ=%s\n", d.timezone))
+	}
+	data.WriteString(fmt.Sprintf("COPY --from=builder /%s /%s\n", packageName, packageName))
+	for v := range d.additionFolders {
+		data.WriteString(fmt.Sprintf("COPY --from=builder /%s/%s /%s/%s\n", packageName, v, packageName, v))
+	}
+	for v := range d.additionFiles {
+		data.WriteString(fmt.Sprintf("COPY --from=builder /%s/%s /%s/%s\n", packageName, v, packageName, v))
+	}
+
+	data.WriteString("USER appuser\n")
+	if d.port != "" {
+		data.WriteString(fmt.Sprintf("EXPOSE %s\n", d.port))
+	}
+	data.WriteString(fmt.Sprintf("ENTRYPOINT [\"/%s\"]\n", packageName))
+
+	err := createDockerfile(data.String())
+
+	return err
+}
+
+func getVersion() string {
+	v := runVer()
+	re := regexp.MustCompile("[0-9.]+")
+	version := re.FindAllString(v, -1)
+	if len(version) == 0 {
+		return defaultTagVersion
+	}
+	return fmt.Sprintf("%s-%s", strings.Join(version, ""), defaultTagVersion)
+}
+
+func getPackageName() string {
+	file, err := openFile(goModFile)
+	if err != nil {
+		return defaultAppName
+	}
+	defer file.Close()
+
+	return parsePackageName(file)
+}
+
+func parsePackageName(r io.Reader) string {
+	reader := bufio.NewReader(r)
+	data, _, err := reader.ReadLine()
+	if err != nil {
+		return defaultAppName
+	}
+
+	module := strings.ReplaceAll(string(data), "module ", "")
+	if string(module[0]) == "\"" {
+		module = strings.ReplaceAll(module, "\"", "")
+	}
+
+	name := strings.Split(module, "/")
+
+	return strings.ReplaceAll(name[len(name)-1], ".", "_")
+}
+
+func getAdditionalFolders() additionalInfo {
+	folders := newAdditionalInfo()
+
+	files, err := getProjectFiles()
+	if err != nil {
+		return folders
+	}
+
+	for _, f := range files {
+		if f.IsDir() && additionalFolders[f.Name()] {
+			folders.set(f.Name())
+		}
+	}
+
+	return folders
+}
+
+func isVendorMode() bool {
+	files, err := getProjectFiles()
+	if err != nil {
+		return false
+	}
+
+	for _, f := range files {
+		if f.IsDir() && f.Name() == vendorFolderName {
+			return true
+		}
+	}
+
+	return false
+}
+
+func getProjectFiles() ([]fs.FileInfo, error) {
+	files, err := readDir("./")
+	if err != nil {
+		return nil, err
+	}
+
+	return files, nil
+}
+
+func createDockerfile(data string) error {
+	return os.WriteFile("Dockerfile", []byte(data), 0644)
+}
+
+func newAdditionalInfo() additionalInfo {
+	return map[string]bool{}
+}
+
+func (a additionalInfo) set(e string) {
+	a[e] = true
+}