gotgen

README

gotgen

Minimalistic Go Template based Generator.

How to use

Install:

go get -u github.com/bitrise-io/gotgen

Init:

gotgen init

to create a gg.conf.json GotGen configuration file in the current directory.

Then run:

gotgen generate

Reads gg.conf.json from the currend directory, parses all the .gg files in the current directory, then runs Go template on all .gg file content, with Inventory defined in the gg.conf.json exposed as Inventory for the Go Template, then saves the generated files with the same name without .gg extension.

In addition to what's available in the standard Go template package gotgen adds a few additional utility functions you can use in your .gg templates. For the complete list see the cmd/generate.go file's createAvailableTemplateFunctions function. A few examples:

• var: {{ var "KeyID" }}: Fail if KeyID isn't specified in the inventory. Otherwise it works the same as {{ .KeyID }} would.
• getenv: {{ getenv "ENV_VAR_KEY" }}: Get the value of ENV_VAR_KEY env var. If the env var does not exist it'll result in an empty string, just like Go's os.Getenv.
• getenvRequired: {{ getenvRequired "ENV_VAR_KEY" }}: Same as getenv but it will fail if the env var isn't set or if its value is an empty string.
• yaml: {{ obj | yaml }}: Generates yaml string for the provided object.
• indentWithSpaces: {{ "some\n multiline\n text" | indentWithSpaces 4 }}: Indents the specified string with the number of spaces you provide.
• add, subtract, multiply, divide, modulo: {{ 6 | add 2 }}: Simple arithmetic functions.

Example config and template file

Example gg.conf.json config file:

{
  "inventory": {
    "KeyBool": true,
    "KeyOne": "value for key one",
    "KeyTwo": 2,
    "Nested": {
      "KeyA": {
        "Key1": "KeyA-Key1 value"
      }
    }
  },
  "delimiter": {
    "left": "{{",
    "right": "}}"
  }
}

Example template file (example.txt.gg):

This is an example GotGen template file.

If you run "gotgen generate" that will create a new file in this directory, with the filename "example.txt".

The gg.conf.json file in this directory includes the Inventory, which can be used in these .gg Go Templates (https://golang.org/pkg/text/template/).

For example, if you run "gotgen generate" now in this directory, the generated "example.txt" file will be generated by including the value of:

- KeyOne here: {{ var "KeyOne" }}
- and KeyTwo here: {{ .KeyTwo }}
- and Nested.KeyA.Key1 here: {{ .Nested.KeyA.Key1 }}

And the following section will be showns based on KeyBool's value:

{{ if .KeyBool }}KeyBool was true{{ else }}KeyBool was false{{ end }}

Environment variables can also be included, with {{ getenv "ENV_VAR_KEY" }},
which will result in an empty string if ENV_VAR_KEY is not set. If you want the template
to fail if the env var isn't set use getenvRequired instead.

Inline yaml embedding:
{{ .Nested | yaml }}

Indentation:
{{ "a\nb\n" | indentWithSpaces 4 }}

Some math:
add: {{ 6 | add 2 }}
subtract: {{ 6 | subtract 2 }}
multiply: {{ 6 | multiply 2 }}
divide: {{ 6 | divide 2 }}
modulo: {{ 6 | modulo 2 }}

That's all you need to know.

GG ;)