gotempl

Small binary used to generate files from Go Templates, environment variables and data files.

The following formats are supported:

• JSON
• YAML
• TOML
• ENV (environment variables in the form "key=value")

Usage

usage: gotempl [--help] [--completion] [--template TEMPLATE [TEMPLATE ...]] [--output OUTPUT] [--data-json DATA-JSON [DATA-JSON ...]] [--data-yaml DATA-YAML [DATA-YAML ...]] [--data-toml DATA-TOML [DATA-TOML ...]] [--data-env DATA-ENV [DATA-ENV ...]]

Generic templating tool which use both environment variables and data files as template data

optional arguments:
  --help, -h                           show this help message
  --completion                         show command completion script
  --html, -H                           Escape template for HTML output
  --template TEMPLATE, -t TEMPLATE     Path to Go Template file. Default is stdin.
  --output OUTPUT, -o OUTPUT           Path to output file. Default is stdout
  --data-json DATA-JSON, -j DATA-JSON  Path to JSON file
  --data-yaml DATA-YAML, -y DATA-YAML  Path to YAML file
  --data-toml DATA-TOML, -T DATA-TOML  Path to TOML file
  --data-env DATA-ENV, -e DATA-ENV     Path to ENV file

Example: Rendering JSON

Let's create a file named sample.json containing the following:

{
  "name": "John Smith"
}

And a file named greeting.template containing the following:

Hello {{ .Data.name }}

Using gotempl, you can then render those files to:

$ gotempl -t greeting.template --data-json sample.json
Hello John Smith

Example: Rendering multiple files

Let's create a file named greeting.yaml containing the following:

greeting:
  polite: Good morning
  informal: Hi

Then a file sample.json containing the following:

{
  "informal": true,
  "name": "John"
}

And finally, a file greeting.template containing the following:

{{- if .Data.informal -}}
{{ .Data.greeting.informal }} {{ .Data.name }}
{{- else -}}
{{ .Data.greeting.polite }} {{ .Data.name }}
{{- end -}}

Using gotempl, you can then render those files to:

$ gotempl -t greeting.template --data-yaml greeting.yaml --data-json sample.json
Hi John

Example: Reading template from stdin

Using the previous sample.json file and gotempl, you can render it to:

$ export GREETING="Hello"
$ cat <<EOF | gotempl --data-json sample.json
{{ .Env.GREETING }} {{ .Data.name }}
EOF
Hello John

Example: Using Sprig

gotempl supports Sprig functions:

$ export STR="hello"
$ cat <<EOF | gotempl
{{ .Env.STR | upper | repeat 5 }}
EOF
HELLOHELLOHELLOHELLOHELLO

Example: Using local file functions

gotempl supports read file functions such as

names	description
isDir, osIsDir	test if input path is a directory
readDir, osReadDir	returns input path files
readFile, osReadFile	returns input path file content
walkDir, osWalkDir	returns recursively input path files and directory content
fileExists, osFileExists	true if input file path exists

$ cat <<EOF | gotempl
{{ isDir "." }}
EOF
true

Contributing

To add a new supported format, you'll need to implement the following interface:

type Decoder {
  Format()        string        // return the format name, used for the --data-*** option
  Shortcut()      string        // return the shortcut option to use
  Decode([]byte)  (Data, error) // unmarhsal the input data
}

The add your implementation to the decoder list in internal/decoder/main.go:

var decoders = []Decoder{
  //...
  MyDecoder{},
}

License

This project is released under the terms of the MIT License.