Initial commit

.gitignore

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+dist/
+tmpl

.goreleaser.yml

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+# Make sure to check the documentation at http://goreleaser.com
+before:
+  hooks:
+    # You may remove this if you don't use go modules.
+    - go mod tidy
+builds:
+  - env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - windows
+      - darwin
+    goarch:
+      - amd64
+      - arm64
+archives:
+  - format: zip
+checksum:
+  name_template: "checksums.txt"
+snapshot:
+  name_template: "{{ .Tag }}-next"
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"

LICENSE

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+Copyright 2022 Krakozaure
+
+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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+# tmpl
+
+`tmpl` allows to apply variables from JSON/TOML/YAML files,
+environment variables or CLI arguments to template files using Golang
+`text/template` and functions from the Sprig project.
+
+## Project status
+
+This project is in a very early stage. Things might break !
+
+## Usage
+
+For simplicity, everything is output on `stdout`. To write the result in a
+file, use shell redirection.
+
+If a variable is not found and the strict mode is disabled (default disabled),
+each missing value will be replaced with an empty string.
+
+- Print help/usage message.
+
+```sh
+# $ tmpl
+# $ tmpl -h
+$ tmpl --help
+USAGE: tmpl [OPTIONS] INPUT
+
+INPUT is a template file or '-' for stdin
+
+OPTIONS:
+  -e    load variables from environment (default true)
+  -f value
+        load variables from JSON/TOML/YAML files (format: file path)
+  -s    exit on any error during template processing (default false)
+  -v value
+        use one or more variables from the command line (format: name=value)
+```
+
+- `stdin` and environment variables.
+
+```sh
+$ echo "Editor = {{ .Env.EDITOR }}, Shell = {{ .Env.SHELL }}" | tmpl -
+Editor = nvim, Shell = /bin/bash
+```
+
+- `stdin` and CLI variables.
+
+```sh
+$ echo "Hello, {{ .foo }} !" | tmpl -v foo=bar -
+Hello, bar !
+```
+
+- Sample from this repository
+
+Output is not pasted here because of its length.
+
+```sh
+$ tmpl -f ./stores/data.yaml ./inputs/sample.txt.tmpl
+```
+
+## Configuration
+
+No configuration needed. Everything is done on the command line.

cli.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+// Allow multiple string values for one flag
+type stringsArray []string
+
+func (s *stringsArray) String() string {
+	return fmt.Sprintf("%v", *s)
+}
+
+func (s *stringsArray) Set(value string) error {
+	*s = append(*s, value)
+	return nil
+}
+
+// Flags
+var (
+	VarsList  stringsArray
+	FilesList stringsArray
+	UseEnv    bool
+	Strict    bool
+)
+
+func initFlags() {
+
+	flag.BoolVar(
+		&UseEnv,
+		"e",
+		true,
+		"load variables from environment",
+	)
+	flag.Var(
+		&FilesList,
+		"f",
+		"load variables from JSON/TOML/YAML files (format: file path)",
+	)
+	flag.Var(
+		&VarsList,
+		"v",
+		"use one or more variables from the command line (format: name=value)",
+	)
+
+	flag.BoolVar(
+		&Strict,
+		"s",
+		false,
+		"exit on any error during template processing (default false)",
+	)
+
+	flag.Usage = func() {
+		fmt.Fprintf(
+			os.Stderr,
+			`USAGE: %s [OPTIONS] INPUT
+
+INPUT is a template file or '-' for stdin
+
+OPTIONS:
+`,
+			os.Args[0],
+		)
+		flag.PrintDefaults()
+	}
+
+	flag.Parse()
+}

context.go

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+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/BurntSushi/toml"
+	"gopkg.in/yaml.v2"
+)
+
+var ctx = make(map[string]interface{})
+
+func loadContext(input string) {
+	ctx["__includeDir__"] = getIncludeDir(input)
+
+	if UseEnv {
+		ctx["Env"] = getEnvVariables()
+	}
+
+	for _, file := range FilesList {
+		for k, v := range getFileVariables(file) {
+			ctx[k] = v
+		}
+	}
+
+	for k, v := range getCliVariables() {
+		ctx[k] = v
+	}
+}
+
+func getIncludeDir(input string) string {
+	// If input is stdin,
+	// template paths are relative to the current working directory
+	// else relative to the input directory
+	if input == "-" {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return "."
+		} else {
+			return cwd
+		}
+	} else {
+		return filepath.Dir(input)
+	}
+}
+
+func getEnvVariables() map[string]string {
+	vars := make(map[string]string)
+	for _, env := range os.Environ() {
+		kv := strings.SplitN(env, "=", 2)
+		vars[kv[0]] = kv[1]
+	}
+	return vars
+}
+
+func getFileVariables(file string) map[string]interface{} {
+	vars := make(map[string]interface{})
+
+	bytes, err := ioutil.ReadFile(file)
+	if err != nil {
+		fmt.Fprint(os.Stderr, fmt.Errorf("unable to read file\n%v\n", err))
+		return vars
+	}
+
+	if strings.HasSuffix(file, ".json") {
+		err = json.Unmarshal(bytes, &vars)
+	} else if strings.HasSuffix(file, ".toml") {
+		err = toml.Unmarshal(bytes, &vars)
+	} else if strings.HasSuffix(file, ".yaml") || strings.HasSuffix(file, ".yml") {
+		err = yaml.Unmarshal(bytes, &vars)
+	} else {
+		err = fmt.Errorf("bad file type: %s", file)
+	}
+	if err != nil {
+		fmt.Fprint(os.Stderr, fmt.Errorf("unable to load data\n%v\n", err))
+	}
+	return vars
+}
+
+func getCliVariables() map[string]string {
+	vars := make(map[string]string)
+	for _, pair := range VarsList {
+		kv := strings.SplitN(pair, "=", 2)
+
+		v := kv[1]
+		if strings.HasPrefix(v, "\"") && strings.HasSuffix(v, "\"") {
+			v = v[1 : len(v)-1]
+		} else if strings.HasPrefix(v, "'") && strings.HasSuffix(v, "'") {
+			v = v[1 : len(v)-1]
+		}
+
+		vars[kv[0]] = v
+	}
+	return vars
+}