Generate file using template from environment, arguments, json/yaml/toml config files.

NAME:
   frep - Generate file using template

USAGE:
   frep [options] input-file[:output-file] ...

VERSION:
   1.3.3-x

AUTHORS:
   Guoqiang Chen <[email protected]>

OPTIONS:
   -e, --env name=value    set variable name=value, can be passed multiple times
       --json jsonstring   load variables from json object string
       --load file         load variables from json/yaml/toml file
       --overwrite         overwrite if destination file exists
       --dryrun            just output result to console instead of file
       --delims value      template tag delimiters (default: {{:}})
       --help              print this usage
       --version           print version information

EXAMPLES:
   frep nginx.conf.in -e webroot=/usr/share/nginx/html -e port=8080
   frep nginx.conf.in:/etc/nginx.conf -e webroot=/usr/share/nginx/html -e port=8080
   frep nginx.conf.in --json '{"webroot": "/usr/share/nginx/html", "port": 8080}'
   frep nginx.conf.in --load config.json --overwrite
   echo "{{ .Env.PATH }}"  | frep -

v1.3.3 Release: https://github.com/subchen/frep/releases/tag/v1.3.3

• Linux

  curl -fSL https://github.com/subchen/frep/releases/download/v1.3.3/frep-1.3.3-linux-amd64 -o /usr/local/bin/frep
  chmod +x /usr/local/bin/frep
  

• macOS

  brew install subchen/tap/frep
  

• Windows

  wget https://github.com/subchen/frep/releases/download/v1.3.3/frep-1.3.3-windows-amd64.exe
  

You can run frep using docker container

docker run -it --rm subchen/frep:1.3.3 --help

• 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 > config.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 config.json
  

• Load from YAML file

  cat > config.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 config.yaml
  

• Load from TOML file

  cat > config.toml << 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 config.toml
  

• Input from file

  // input file: nginx.conf
  frep nginx.conf.in
  

• Input from console(stdin)

  // input from stdin pipe
  echo "{{ .Env.PATH }}" | frep -
  

• Output to default file (Removed last file ext)

  // output file: nginx.conf
  frep nginx.conf.in --overwrite
  

• Output to the specified file

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

• Output to console(stdout)

  frep nginx.conf.in --dryrun
  frep nginx.conf.in:-
  

• Output multiple files

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

Templates use Golang text/template.

You can access environment variables within a template

Env.PATH = {{ .Env.PATH }}

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

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

There are some built-in functions as well: Masterminds/sprig v2.14.1

• github: https://github.com/Masterminds/sprig
• doc: http://masterminds.github.io/sprig/

More funcs added:

• toJson
• toYaml
• toToml
• fileSize
• fileLastModified
• fileGetBytes
• fileGetString

Sample of nginx.conf.in

server {
    listen {{.port}} default_server;

    root {{.webroot | default "/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 }}
}