Usage

The simplest usage of gomplate is to just replace environment variables. All environment variables are available by referencing .Env (or getenv) in the template.

The template is read from standard in, and written to standard out.

Use it like this:

$ echo "Hello, {{.Env.USER}}" | gomplate
Hello, hairyhenderson

Commandline Arguments

--file/-f, --in/-i, and --out/-o

By default, gomplate will read from Stdin and write to Stdout. This behaviour can be changed.

  • Use --file/-f to use a specific input template file. The special value - means Stdin.
  • Use --out/-o to save output to file. The special value - means Stdout.
  • Use --in/-i if you want to set the input template right on the commandline. This overrides --file. Because of shell command line lengths, it’s probably not a good idea to use a very long value with this argument.

Multiple inputs

You can specify multiple --file and --out arguments. The same number of each much be given. This allows gomplate to process multiple templates slightly faster than invoking gomplate multiple times in a row.

--input-dir and --output-dir

For processing multiple templates in a directory you can use --input-dir and --output-dir together. In this case all files in input directory will be processed as templates and the resulting files stored in --output-dir. The output directory will be created if it does not exist and the directory structure of the input directory will be preserved.

Example:

 # Process all files in directory "templates" with the datasource given
 # and store the files with the same directory structure in "config"
gomplate --input-dir=templates --output-dir=config --datasource config=config.yaml

--chmod

By default, output files are created with the same file mode (permissions) as input files. If desired, the --chmod option can be used to override this behaviour, and set the output file mode explicitly. This can be useful for creating executable scripts or ensuring write permissions.

The value must be an octal integer in the standard UNIX chmod format, i.e. 644 to indicate that owner gets read+write, group gets read-only, and others get read-only permissions. See the chmod(1) man page for more details.

--exclude

To prevent certain files from being processed, you can use --exclude. It takes a glob, and any files matching that glob will not be included.

Example:

$ gomplate --exclude example/** --exclude *.png

This will stop all files in the example folder from being processed, as well as all .png files in the current folder.

You can also chain the flag to build up a series of globs to be excluded.

--datasource/-d

Add a data source in name=URL form. Specify multiple times to add multiple sources. The data can then be used by the datasource and include functions.

See Datasources for full details.

A few different forms are valid: - mydata=file:///tmp/my/file.json - Create a data source named mydata which is read from /tmp/my/file.json. This form is valid for any file in any path. - mydata=file.json - Create a data source named mydata which is read from file.json (in the current working directory). This form is only valid for files in the current directory. - mydata.json - This form infers the name from the file name (without extension). Only valid for files in the current directory.

--context/c

Add a data source in name=URL form, and make it available in the [default context][] as .<name>. The special name . (period) can be used to override the entire default context.

All other rules for the --datasource/-d flag apply.

Overriding the template delimiters

Sometimes it’s necessary to override the default template delimiters ({{/}}). Use --left-delim/--right-delim or set $GOMPLATE_LEFT_DELIM/$GOMPLATE_RIGHT_DELIM.

--template/-t

Add a nested template that can be referenced by the main input template(s) with the template built-in. Specify multiple times to add multiple template references.

A few different forms are valid:

  • --template mytemplate.t
    • References a file mytemplate.t in the current working directory.
    • It will be available as a template named mytemplate.t: console $ gomplate --template helloworld.tmpl -i 'here are the contents of the template: [ {{ template "helloworld.tmpl" }} ]' here are the contents of the template: [ hello, world! ]
  • --template path/to/mytemplate.t
    • References a file mytemplate.t in the path path/to/.
    • It will be available as a template named path/to/mytemplate.t: console $ gomplate --template foo/bar/helloworld.tmpl -i 'here are the contents of the template: [ {{ template "foo/bar/helloworld.tmpl" }} ]' here are the contents of the template: [ hello, world! ]
  • --template path/to/
    • Makes available all files in the path path/to/.
    • Any files within this path can be referenced: console $ gomplate --template foo/bar/ -i 'here are the contents of the template: [ {{ template "foo/bar/helloworld.tmpl" }} ]' here are the contents of the template: [ hello, world! ]
  • --template alias=path/to/mytemplate.t
    • References a file mytemplate.t in the path path/to/
    • It will be available as a template named alias: console $ gomplate --template t=foo/bar/helloworld.tmpl -i 'here are the contents of the template: [ {{ template "t" }} ]' here are the contents of the template: [ hello, world! ]
  • --template alias=path/to/
    • Makes available all files in the path path/to/.
    • Any files within this path can be referenced, with the path replaced with alias: console $ gomplate --template dir=foo/bar/ -i 'here are the contents of the template: [ {{ template "dir/helloworld.tmpl" }} ]' here are the contents of the template: [ hello, world! ]

Post-template command execution

Gomplate can launch other commands when template execution is successful. Simply add the command to the command-line after a -- argument:

$ gomplate -i 'hello world' -o out.txt -- cat out.txt
hello world