Initial version

.gobuilder.yml

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+build_matrix:
+  general:
+    ldflags:
+      - "-X main.version $(git describe --tags)"

README.md

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+# Luzifer / envrun
+
+`envrun` is a small helper utility I wrote for myself to debug programs and scripts during their development expecting environment variables to be set to special values. Sure there is [gin]() for go webservers doing the same but I wanted something also for commandline utilities.
+
+It reads a `.env` file (configurable) from the current directory and then either takes its own environment variables or a clean set and adds the env variables found in `.env` to it. The resulting set is passed to the command you put as arguments to `envrun`.
+
+## Examples
+
+To visualize the effect of the utility the test command is `python test.py` with this simple python script:
+
+```python
+import os
+
+for k in os.environ.keys():
+  print "{} = {}".format(k, os.environ[k])
+```
+
+It just prints the current environment to `STDOUT` and exits.
+
+```bash
+# cat .env
+MY_TEST_VAR=hello world
+ANOTHER_VAR=foo
+
+# python test.py | grep MY_TEST_VAR
+## No output on this command
+
+# envrun --help
+Usage of envrun:
+      --clean[=false]: Do not pass current environment to child process
+      --env-file=".env": Location of the environment file
+      --q[=false]: Suppress informational messages from envrun
+
+# envrun python test.py | grep MY_TEST_VAR
+MY_TEST_VAR = hello world
+
+# envrun python test.py | wc -l
+      45
+
+# envrun --clean python test.py | wc -l
+       3
+
+# envrun --clean python test.py
+__CF_USER_TEXT_ENCODING = 0x1F5:0x0:0x0
+ANOTHER_VAR = foo
+MY_TEST_VAR = hello world
+```

main.go

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+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/Luzifer/rconfig"
+)
+
+var (
+	version = "dev"
+	cfg     = struct {
+		EnvFile  string `flag:"env-file" default:".env" description:"Location of the environment file"`
+		Silent   bool   `flag:"q" default:"false" description:"Suppress informational messages from envrun"`
+		CleanEnv bool   `flag:"clean" default:"false" description:"Do not pass current environment to child process"`
+	}{}
+)
+
+func init() {
+	rconfig.Parse(&cfg)
+}
+
+func infoLog(message string, args ...interface{}) {
+	if !cfg.Silent {
+		log.Printf(message, args...)
+	}
+}
+
+func envListToMap(list []string) map[string]string {
+	out := map[string]string{}
+	for _, entry := range list {
+		if len(entry) == 0 {
+			continue
+		}
+
+		parts := strings.SplitN(entry, "=", 2)
+		out[parts[0]] = parts[1]
+	}
+	return out
+}
+
+func envMapToList(envMap map[string]string) []string {
+	out := []string{}
+	for k, v := range envMap {
+		out = append(out, k+"="+v)
+	}
+	return out
+}
+
+func main() {
+	body, err := ioutil.ReadFile(cfg.EnvFile)
+	if err != nil {
+		log.Fatalf("Could not read env-file: %s", err)
+	}
+
+	var childenv map[string]string
+	if cfg.CleanEnv {
+		childenv = map[string]string{}
+	} else {
+		childenv = envListToMap(os.Environ())
+	}
+
+	pairs := envListToMap(strings.Split(string(body), "\n"))
+	for k, v := range pairs {
+		childenv[k] = v
+	}
+
+	c := exec.Command(rconfig.Args()[1], rconfig.Args()[2:]...)
+	c.Env = envMapToList(childenv)
+	c.Stdout = os.Stdout
+	c.Stderr = os.Stderr
+	c.Stdin = os.Stdin
+
+	err = c.Run()
+
+	switch err.(type) {
+	case nil:
+		infoLog("Process exitted with code 0")
+		os.Exit(0)
+	case *exec.ExitError:
+		infoLog("Unclean exit with exit-code != 0")
+		os.Exit(1)
+	default:
+		log.Printf("An unknown error ocurred: %s", err)
+		os.Exit(2)
+	}
+}