From 5c439f89535ed82d38c2dacf11d81b34ad3cbe44 Mon Sep 17 00:00:00 2001
From: Marcel Ludwig <marclud8@gmail.com>
Date: Sat, 2 Sep 2017 10:25:46 +0200
Subject: [PATCH] added inline option

excluded windows from travis
uploading linux and darwin bins on release
removed caps restriction to env vars

removed osx from travis builds too

fixed missing err handling for writer flush
---
 .travis.yml | 15 ++++++--------
 README.md   | 15 ++++++++++----
 cli/cli.go  | 59 ++++++++++++++++++++++++++++++++++++++---------------
 3 files changed, 60 insertions(+), 29 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 333bef1..0eb96bd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,26 +1,25 @@
 language: go
 env:
   - GIMME_OS=linux GIMME_ARCH=amd64
-  - GIMME_OS=darwin GIMME_ARCH=amd64
-  - GIMME_OS=windows GIMME_ARCH=amd64
+#  - GIMME_OS=darwin GIMME_ARCH=amd64
+#  - GIMME_OS=windows GIMME_ARCH=amd64
 sudo: required
 go:
-  - 1.6.3
-  - 1.7
-  - 1.8.3
+  - 1.9
   - tip
 install:
   - go get -d -v -t ./...
 script:
   - export GOMAXPROCS=$(nproc) GOOS=$GIMME_OS GOARCH=$GIMME_ARCH
   # TODO test seems to fail on non linux platforms @ travis
-#  - go test -v -timeout=30s ./...
+  - go test -v -timeout=30s ./...
   - go build -o tg ./cli/cli.go
 deploy:
   provider: releases
   api_key:
     secure: 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
-  file: tg
+  file:
+  - tg
   skip_cleanup: true
   on:
     tags: true
@@ -28,5 +27,3 @@ matrix:
   fast_finish: true
   allow_failures:
   - go: tip
-  exclude:
-  - go: 1.6.3
\ No newline at end of file
diff --git a/README.md b/README.md
index 2b0e15d..b09ce23 100644
--- a/README.md
+++ b/README.md
@@ -6,17 +6,24 @@ Environment variable based template engine like Jinja2 for your container config
 
 ## Usage
 
-Define variables with the format `{{ VAR_IABLE }}` and set them in your environment before **tg** execution.
+Define variables with the format `{{ VAR_IABLE }}` inside your template files and set them in your environment before **tg** execution.
 
-Currently with stdin/stdout support.
- ```
+Currently with stdin/stdout and inline support.
+ 
+ ```bash
+# pipe
 TESTVAR=foo cat /opt/templates/file1.ext | tg > /dest/config/file1.ext
+# or inline
+TESTVAR=foo tg -i /dest/config/file1.ext
  ```
+ 
+However, using the inline option on your templates will overwrite them.
+It is recommended to use this option on resettable files.
 
 ### TODO
 * flags for file in/out
 * prefix flag for env var e.g. SERVICE_XXX
 
-### Licence
+### License
 
 MIT
diff --git a/cli/cli.go b/cli/cli.go
index a75be6f..77f9150 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -1,40 +1,67 @@
 package main
 
 import (
-	"fmt"
-	"github.com/malud/temgo/temgo"
+	"bufio"
+	"flag"
 	"io/ioutil"
 	"os"
 	"strings"
+
+	"github.com/malud/temgo/temgo"
 )
 
 var envVars = make(temgo.EnvVars)
+var inlineFlag = flag.String("i", "", "-i filename")
 
-// Initialize and filter all non upper case variables.
 func init() {
 	for _, e := range os.Environ() {
 		string := strings.Split(e, "=")
-		if strings.Compare(string[0], strings.ToUpper(string[0])) == 0 {
-			envVars[string[0]] = string[1]
-		}
+		envVars[string[0]] = string[1]
+	}
+
+	if !flag.Parsed() {
+		flag.Parse()
 	}
 }
 
 func main() {
-	var writeErr error
-	input := os.Stdin
-	bytes, err := ioutil.ReadAll(input)
-	if err != nil {
-		_, writeErr = os.Stderr.WriteString(fmt.Sprintf("Could not read: %v", err))
+	var rw *bufio.ReadWriter
+	var file *os.File
+	if *inlineFlag != "" {
+		var err error
+		file, err = os.OpenFile(*inlineFlag, os.O_RDWR, 644)
+		must(err)
+		defer file.Close()
+		rw = bufio.NewReadWriter(bufio.NewReader(file), bufio.NewWriter(file))
+	} else {
+		rw = bufio.NewReadWriter(bufio.NewReader(os.Stdin), bufio.NewWriter(os.Stdout))
 	}
+
+	bytes, err := ioutil.ReadAll(rw)
+	must(err)
+
 	if temgo.ContainsVariable(bytes) {
 		str := envVars.ReplaceVariables(bytes)
-		_, err = os.Stdout.Write(str)
-		if err != nil {
-			_, writeErr = os.Stderr.WriteString(fmt.Sprintf("Could not write: %v", err))
+		if file != nil {
+			truncate(file)
 		}
+		_, err := rw.Write(str)
+		must(err)
+		must(rw.Flush())
 	}
-	if writeErr != nil {
-		panic(writeErr)
+}
+
+// fatal
+func must(err error) {
+	if err != nil {
+		println("Err:", err.Error())
+		os.Exit(1)
 	}
 }
+
+func truncate(file *os.File) {
+	err := file.Truncate(0)
+	must(err)
+	_, err = file.Seek(0, 0)
+	must(err)
+}