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Initial version

This commit is contained in:
Knut Ahlers 2016-02-06 16:23:11 +01:00
commit 352e593d8d
3 changed files with 141 additions and 0 deletions

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.gobuilder.yml Normal file
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build_matrix:
general:
ldflags:
- "-X main.version $(git describe --tags)"

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README.md Normal file
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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
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# 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
```

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main.go Normal file
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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)
}
}