First release of the kroki CLI (#1)

.travis.yml

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+language: go
+
+go:
+  - "1.11.x"
+
+env:
+- GO111MODULE=on GOLANGCI_LINT_VERSION=1.12.5
+
+install:
+- curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $GOPATH/bin v${GOLANGCI_LINT_VERSION}
+- go mod vendor
+
+script:
+- go test -race ./...
+- golangci-lint run .

README.adoc

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+= Kroki CLI
+
+image:https://travis-ci.org/yuzutech/kroki-cli.svg?branch=master[Build Status,link=https://travis-ci.org/yuzutech/kroki-cli]
+
+A CLI for https://kroki.io.
+
+== Usage
+
+ kroki convert hello.dot
+
+By default the diagram type will be inferred from the diagram file extension and the default output format will be `SVG`.
+
+Long format:
+
+ kroki convert hello.dot --type dot --format svg
+
+The output format can also be inferred from the output file using the `--out-file` flag:
+
+ kroki convert simple.er --out-file out.png
+
+Read from `stdin`:
+
+ cat hello.dot | kroki convert - -t dot
+
+By default when reading from `stdin` using `-`, the result will be output to `stdout`.
+If you want to output to a file you can use `-o`:
+
+ cat hello.dot | kroki convert - -t dot -o out.png
+
+Similarly, you can also output to `stdout` when reading from a file using the special value `-` with the `--out-file` flag:
+
+ kroki convert simple.er --out-file -
+
+== Configuration
+
+To configure the endpoint, you can use a configuration file.
+The CLI will look for the following locations:
+
+* `/etc/kroki.yml`
+* `$HOME/kroki.yml`
+* `kroki.yml`
+
+You can also specify an alternate config file using the `--config` flag:
+
+ kroki convert hello.dot --config config.yml
+
+The config file should contain the endpoint URL and the HTTP timeout.
+By default Kroki will use the demonstration server: https://demo.kroki.io and a timeout of 20 seconds.
+
+CAUTION: Please note that the demonstration server usage is restricted to reasonable, non-commercial use-cases.
+We provide no guarantee regarding uptime or latency.
+
+Example:
+
+.kroki.yml
+```yml
+endpoint: 'https://localhost:8000'
+timeout: 30s
+```
+
+If you don't want to use a file you can also use the following environment variables:
+
+* `KROKI_ENDPOINT`
+* `KROKI_TIMEOUT`
+
+[]
+
+ KROKI_ENDPOINT=https://localhost:8000 KROKI_TIMEOUT=1m kroki convert hello.dot

cmd/config.go

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+package cmd
+
+import "github.com/spf13/viper"
+
+func SetupConfig() {
+	// Default values
+	viper.SetDefault("endpoint", "https://demo.kroki.io")
+	viper.SetDefault("timeout", "20s")
+
+	// Config file name
+	viper.SetConfigName("kroki")
+
+	// Default config paths
+	viper.AddConfigPath("/etc")
+	viper.AddConfigPath("$HOME")
+	viper.AddConfigPath(".")
+
+	// Environment variables
+	viper.SetEnvPrefix("kroki")
+	err := viper.BindEnv("endpoint")
+	if err != nil {
+		exit(err)
+	}
+	err = viper.BindEnv("timeout")
+	if err != nil {
+		exit(err)
+	}
+}
+
+
+func InitDefaultConfig() {
+	viper.ReadInConfig() // ignore error
+}

cmd/convert.go

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+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"github.com/yuzutech/kroki-go"
+)
+
+func Convert(cmd *cobra.Command, args []string) {
+	filePath := args[0]
+	graphFormat, err := cmd.Flags().GetString("type")
+	if err != nil {
+		exit(err)
+	}
+	imageFormat, err := cmd.Flags().GetString("format")
+	if err != nil {
+		exit(err)
+	}
+	outFile, err := cmd.Flags().GetString("out-file")
+	if err != nil {
+		exit(err)
+	}
+	client := GetClient(cmd)
+	if filePath == "-" {
+		reader := bufio.NewReader(os.Stdin)
+		ConvertFromReader(client, graphFormat, imageFormat, outFile, reader)
+	} else {
+		ConvertFromFile(client, filePath, graphFormat, imageFormat, outFile)
+	}
+}
+
+func ConvertFromReader(client kroki.Client, diagramTypeRaw string, imageFormatRaw string, outFile string, reader io.Reader) {
+	if diagramTypeRaw == "" {
+		exit("diagram type must be specify using --type flag")
+	}
+	diagramType, err := GraphFormatFromValue(diagramTypeRaw)
+	if err != nil {
+		exit(err)
+	}
+	imageFormat, err := ResolveImageFormat(imageFormatRaw, outFile)
+	if err != nil {
+		exit(err)
+	}
+	text, err := GetTextFromReader(reader)
+	if err != nil {
+		exit(err)
+	}
+	result, err := client.FromString(text, diagramType, imageFormat)
+	if err != nil {
+		exit(err)
+	}
+	if outFile == "" || outFile == "-" {
+		fmt.Println(result)
+	} else {
+		err = client.WriteToFile(outFile, result)
+		if err != nil {
+			exit(err)
+		}
+	}
+}
+
+func GetTextFromReader(reader io.Reader) (result string, err error) {
+	input, err := ioutil.ReadAll(reader)
+	return string(input), err
+}
+
+func ConvertFromFile(client kroki.Client, filePath string, graphFormatRaw string, imageFormatRaw string, outFile string) {
+	graphFormat, err := ResolveGraphFormat(graphFormatRaw, filePath)
+	if err != nil {
+		exit(err)
+	}
+	imageFormat, err := ResolveImageFormat(imageFormatRaw, outFile)
+	if err != nil {
+		exit(err)
+	}
+	result, err := client.FromFile(filePath, graphFormat, imageFormat)
+	if err != nil {
+		exit(err)
+	}
+	if outFile == "-" {
+		fmt.Println(result)
+	} else {
+		err = client.WriteToFile(ResolveOutputFilePath(outFile, filePath, imageFormat), result)
+		if err != nil {
+			exit(err)
+		}
+	}
+}
+
+func ResolveOutputFilePath(outFile string, filePath string, imageFormat kroki.ImageFormat) string {
+	if outFile != "" {
+		return outFile
+	}
+	fileExtension := path.Ext(filePath)
+	return filePath[0:len(filePath)-len(fileExtension)] + "." + string(imageFormat)
+}
+
+func ResolveImageFormat(imageFormatRaw string, outFile string) (kroki.ImageFormat, error) {
+	if imageFormatRaw == "" {
+		if outFile == "" || outFile == "-" {
+			return kroki.Svg, nil
+		}
+		return ImageFormatFromFile(outFile)
+	}
+	return ImageFormatFromValue(imageFormatRaw)
+}
+
+func ImageFormatFromValue(imageFormatRaw string) (kroki.ImageFormat, error) {
+	value := strings.ToLower(imageFormatRaw)
+	switch value {
+	case "svg":
+		return kroki.Svg, nil
+	case "png":
+		return kroki.ImageFormat("png"), nil
+	case "jpeg":
+		return kroki.ImageFormat("jpeg"), nil
+	case "pdf":
+		return kroki.ImageFormat("pdf"), nil
+	default:
+		return kroki.ImageFormat(""), errors.Errorf(
+			"invalid image format %s.",
+			value)
+	}
+}
+
+func ImageFormatFromFile(filePath string) (kroki.ImageFormat, error) {
+	fileExtension := filepath.Ext(filePath)
+	value := strings.ToLower(fileExtension)
+	switch value {
+	case ".svg":
+		return kroki.Svg, nil
+	case ".png":
+		return kroki.ImageFormat("png"), nil
+	case ".jpeg", ".jpg":
+		return kroki.ImageFormat("jpeg"), nil
+	case ".pdf":
+		return kroki.ImageFormat("pdf"), nil
+	default:
+		return kroki.ImageFormat(""), errors.Errorf(
+			"invalid image format %s.",
+			value)
+	}
+}
+
+func ResolveGraphFormat(graphFormatRaw string, filePath string) (kroki.GraphFormat, error) {
+	if graphFormatRaw == "" {
+		return GraphFormatFromFile(filePath)
+	} else {
+		return GraphFormatFromValue(graphFormatRaw)
+	}
+}
+
+func GraphFormatFromValue(value string) (kroki.GraphFormat, error) {
+	value = strings.ToLower(value)
+	switch value {
+	case "dot", "graphviz":
+		return kroki.Graphviz, nil
+	case "plantuml":
+		return kroki.Plantuml, nil
+	case "nomnoml":
+		return kroki.Nomnoml, nil
+	case "blockdiag":
+		return kroki.BlockDiag, nil
+	case "mermaid":
+		return kroki.Mermaid, nil
+	case "svgbob":
+		return kroki.Svgbob, nil
+	case "umlet":
+		return kroki.Umlet, nil
+	case "c4plantuml":
+		return kroki.C4plantuml, nil
+	case "seqdiag":
+		return kroki.SeqDiag, nil
+	case "erd", "er":
+		return kroki.GraphFormat("erd"), nil
+	case "nwdiag":
+		return kroki.GraphFormat("nwdiag"), nil
+	case "actdiag":
+		return kroki.GraphFormat("actdiag"), nil
+	case "ditaa":
+		return kroki.GraphFormat("ditaa"), nil
+	default:
+		return kroki.GraphFormat(""), errors.Errorf(
+			"invalid graph format %s.",
+			value)
+	}
+}
+
+func GraphFormatFromFile(filePath string) (kroki.GraphFormat, error) {
+	fileExtension := filepath.Ext(filePath)
+	value := strings.ToLower(fileExtension)
+	switch value {
+	case ".dot", ".gv", ".graphviz":
+		return kroki.Graphviz, nil
+	case ".puml", ".plantuml":
+		return kroki.Plantuml, nil
+	case ".nomnoml":
+		return kroki.Nomnoml, nil
+	case ".blockdiag":
+		return kroki.BlockDiag, nil
+	case ".mermaid":
+		return kroki.Mermaid, nil
+	case ".svgbob":
+		return kroki.Svgbob, nil
+	case ".umlet":
+		return kroki.Umlet, nil
+	case ".c4puml", ".c4", ".c4plantuml":
+		return kroki.C4plantuml, nil
+	case ".seqdiag":
+		return kroki.SeqDiag, nil
+	case ".erd", ".er":
+		return kroki.GraphFormat("erd"), nil
+	case ".nwdiag":
+		return kroki.GraphFormat("nwdiag"), nil
+	case ".actdiag":
+		return kroki.GraphFormat("actdiag"), nil
+	case ".ditaa":
+		return kroki.GraphFormat("ditaa"), nil
+	default:
+		return kroki.GraphFormat(""), errors.Errorf(
+			"unable to infer the graph format from the file extension %s, please specify the diagram type using --type flag.",
+			value)
+	}
+}
+
+func GetClient(cmd *cobra.Command) kroki.Client {
+	configFilePath, err := cmd.Flags().GetString("config")
+	if err != nil {
+		exit(err)
+	}
+	if configFilePath != "" {
+		file, err := os.Open(configFilePath)
+		if err != nil {
+			exit(err)
+		}
+		err = viper.ReadConfig(file)
+		if err != nil {
+			exit(err)
+		}
+	}
+	return kroki.New(kroki.Configuration{
+		URL:     viper.GetString("endpoint"),
+		Timeout: viper.GetDuration("timeout"),
+	})
+}