frep

frep

A template file replace tool written golang

Usage: frep [OPTIONS] input-file:[output-file] ...
   or: frep [ --version | --help ]

Transform template file using environment, arguments, json/yaml files

Options:
  -e, --env=[]      set variable name=value, can be passed multiple times
  --json=string     load variables from json object
  --load=[]         load variables from json/yaml files
  --overwrite       overwrite if destination file exists
  --testing         test mode, output transform result to console
  --delims={{:}}    template tag delimiters
  --version         show version information
  --help            show this help

Downloads

frep-1.0.1

Linux amd64

curl -fSL https://github.com/subchen/frep/releases/download/v1.0.1/frep-linux-amd64.zip -o frep.zip
sudo unzip frep.zip -d /usr/bin/

OS X

curl -fSL https://github.com/subchen/frep/releases/download/v1.0.1/frep-darwin-amd64.zip -o frep.zip
sudo unzip frep.zip -d /usr/bin/

Examples

Load template variables

Load from environment

export webroot=/usr/share/nginx/html
export port=8080
frep nginx.conf.in

Load from arguments

frep nginx.conf.in -e webroot=/usr/share/nginx/html -e port=8080

Load from JSON String

frep nginx.conf.in --json '{"webroot": "/usr/share/nginx/html", "port": 8080}'

Load from JSON file

cat > ctx.json << EOF
{
  "webroot": "/usr/share/nginx/html",
  "port": 8080,
  "servers": [
    "127.0.0.1:8081",
    "127.0.0.1:8082"
  ]
}
EOF

frep nginx.conf.in --load ctx.json

Load from Yaml file

cat > ctx.yaml << EOF
webroot: /usr/share/nginx/html
port: 8080
servers:
  - 127.0.0.1:8081
  - 127.0.0.1:8082
EOF

frep nginx.conf.in --load ctx.yaml

Output

Output to default file (auto remove last file ext)

frep nginx.conf.in --overwrite

Output to specified file

frep nginx.conf.in:/etc/nginx.conf --overwrite -e port=8080

Output to console

frep nginx.conf.in --testing

Output multiple files

frep nginx.conf.in redis.conf.in ...

Others

If your file uses {{ and }} as part of it's syntax, you can change the template escape characters using the -delims.

frep --delims "<%:%>" ...

Template file

Templates use Golang text/template. You can access environment variables within a template

ENV.PATH = {{ .PATH }}

There are a few built in functions as well:

• default $var $default - Returns a default value for one that does not exist. {{ default .VERSION "0.1.2" }}
• split $string $sep - Splits a string into an array using a separator string. Alias for strings.Split. {{ split .PATH ":" }}

nginx.conf.in

server {
    listen {{.port}} default_server;

    root {{default .webroot "/usr/share/nginx/html"}};
    index index.html index.htm;

    location /api {
        access_log off;
        proxy_pass http://backend;
    }
}

upstream backend {
    ip_hash;
{{range .servers}}
    server {{.}};
{{end}}
}