Add include function

Signed-off-by: Dave Henderson <[email protected]>

data.go

@@ -200,6 +200,19 @@ func (d *Data) Datasource(alias string, args ...string) interface{} {
 	return nil
 }
 
+// Include -
+func (d *Data) include(alias string, args ...string) interface{} {
+	source, ok := d.Sources[alias]
+	if !ok {
+		log.Fatalf("Undefined datasource '%s'", alias)
+	}
+	b, err := d.ReadSource(source.FS, source, args...)
+	if err != nil {
+		log.Fatalf("Couldn't read datasource '%s': %s", alias, err)
+	}
+	return string(b)
+}
+
 // ReadSource -
 func (d *Data) ReadSource(fs vfs.Filesystem, source *Source, args ...string) ([]byte, error) {
 	if d.cache == nil {

data_test.go

@@ -271,3 +271,28 @@ func TestParseHeaderArgs(t *testing.T) {
 	}
 	assert.Equal(t, expected, parseHeaderArgs(args))
 }
+
+func TestInclude(t *testing.T) {
+	ext := "txt"
+	contents := "hello world"
+	fname := "foo." + ext
+	fs := memfs.Create()
+	_ = fs.Mkdir("/tmp", 0777)
+	f, _ := vfs.Create(fs, "/tmp/"+fname)
+	_, _ = f.Write([]byte(contents))
+
+	sources := map[string]*Source{
+		"foo": {
+			Alias: "foo",
+			URL:   &url.URL{Scheme: "file", Path: "/tmp/" + fname},
+			Ext:   ext,
+			Type:  "text/plain",
+			FS:    fs,
+		},
+	}
+	data := &Data{
+		Sources: sources,
+	}
+	actual := data.include("foo")
+	assert.Equal(t, contents, actual)
+}

docs/content/functions.md

@@ -704,6 +704,51 @@ no worries
 
 Alias to [`datasource`](#datasource)
 
+## `include`
+
+Includes the content of a given datasource (provided by the [`--datasource/-d`](../usage/#datasource-d) argument).
+
+This is similar to [`datasource`](#datasource),
+except that the data is not parsed.
+
+### Usage
+
+```go
+include alias [subpath]
+```
+
+### Arguments
+
+| name   | description |
+|--------|-------|
+| `alias` | the datasource alias, as provided by [`--datasource/-d`](../usage/#datasource-d) |
+| `subpath` | _(optional)_ the subpath to use, if supported by the datasource |
+
+### Examples
+
+_`person.json`:_
+```json
+{ "name": "Dave" }
+```
+
+_`input.tmpl`:_
+```go
+{
+  "people": [
+    {{ include "person" }}
+  ]
+}
+```
+
+```console
+$ gomplate -d person.json -f input.tmpl
+{
+  "people": [
+    { "name": "Dave" }
+  ]
+}
+```
+
 ## `ec2meta`
 
 Queries AWS [EC2 Instance Metadata](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html) for information. This only retrieves data in the `meta-data` path -- for data in the `dynamic` path use `ec2dynamic`.

docs/content/usage.md

@@ -44,7 +44,7 @@ gomplate --input-dir=templates --output-dir=config --datasource config=config.ya
 
 ## `--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`](#datasource) function.
+Add a data source in `name=URL` form. Specify multiple times to add multiple sources. The data can then be used by the [`datasource`](../functions/#datasource) and [`include`](../functions/#include) functions.
 
 A few different forms are valid:
 - `mydata=file:///tmp/my/file.json`

gomplate.go

@@ -81,6 +81,7 @@ func NewGomplate(data *Data, leftDelim, rightDelim string) *Gomplate {
 			"datasource":       data.Datasource,
 			"ds":               data.Datasource,
 			"datasourceExists": data.DatasourceExists,
+			"include":          data.include,
 		},
 	}
 }

test/integration/datasources_file.bats

@@ -40,3 +40,10 @@ function teardown () {
   [[ "${output}" == "foo\"
 bar" ]]
 }
+
+@test "'include' doesn't parse file" {
+  echo 'foo: bar' > $tmpdir/config.yml
+  gomplate -d config=$tmpdir/config.yml -i '{{include "config"}}'
+  [ "$status" -eq 0 ]
+  [[ "${output}" == "foo: bar" ]]
+}