provider/local: Implement a new local_file resource

This commit adds the ability to provision files locally.
This is useful for cases where TerraForm generates assets
such as TLS certificates or templated documents that need
to be saved locally.

- While output variables can be used to return values to
the user, it is not extremly suitable for large content or
when many of these are generated, nor is it practical for
operators to manually save them on disk.
- While `local-exec` could be used with an `echo`, this
provider works across platforms and do not require any
convoluted escaping.

builtin/bins/provider-localfile/main.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+	"github.com/hashicorp/terraform/builtin/providers/localfile"
+	"github.com/hashicorp/terraform/plugin"
+)
+
+func main() {
+	plugin.Serve(&plugin.ServeOpts{
+		ProviderFunc: localfile.Provider,
+	})
+}

builtin/providers/local/provider.go

@@ -0,0 +1,15 @@
+package local
+
+import (
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func Provider() terraform.ResourceProvider {
+	return &schema.Provider{
+		Schema: map[string]*schema.Schema{},
+		ResourcesMap: map[string]*schema.Resource{
+			"local_file": resourceLocalFile(),
+		},
+	}
+}

builtin/providers/local/provider_test.go

@@ -0,0 +1,18 @@
+package local
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+var testProviders = map[string]terraform.ResourceProvider{
+	"local": Provider(),
+}
+
+func TestProvider(t *testing.T) {
+	if err := Provider().(*schema.Provider).InternalValidate(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}

builtin/providers/local/resource_local_file.go

@@ -0,0 +1,84 @@
+package local
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"io/ioutil"
+	"os"
+	"path"
+
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func resourceLocalFile() *schema.Resource {
+	return &schema.Resource{
+		Create: resourceLocalFileCreate,
+		Read:   resourceLocalFileRead,
+		Delete: resourceLocalFileDelete,
+
+		Schema: map[string]*schema.Schema{
+			"content": {
+				Type:     schema.TypeString,
+				Required: true,
+				ForceNew: true,
+			},
+			"filename": {
+				Type:        schema.TypeString,
+				Description: "Path to the output file",
+				Required:    true,
+				ForceNew:    true,
+			},
+		},
+	}
+}
+
+func resourceLocalFileRead(d *schema.ResourceData, _ interface{}) error {
+	// If the output file doesn't exist, mark the resource for creation.
+	outputPath := d.Get("filename").(string)
+	if _, err := os.Stat(outputPath); os.IsNotExist(err) {
+		d.SetId("")
+		return nil
+	}
+
+	// Verify that the content of the destination file matches the content we
+	// expect. Otherwise, the file might have been modified externally and we
+	// must reconcile.
+	outputContent, err := ioutil.ReadFile(outputPath)
+	if err != nil {
+		return err
+	}
+
+	outputChecksum := sha1.Sum([]byte(outputContent))
+	if hex.EncodeToString(outputChecksum[:]) != d.Id() {
+		d.SetId("")
+		return nil
+	}
+
+	return nil
+}
+
+func resourceLocalFileCreate(d *schema.ResourceData, _ interface{}) error {
+	content := d.Get("content").(string)
+	destination := d.Get("filename").(string)
+
+	destinationDir := path.Dir(destination)
+	if _, err := os.Stat(destinationDir); err != nil {
+		if err := os.MkdirAll(destinationDir, 0777); err != nil {
+			return err
+		}
+	}
+
+	if err := ioutil.WriteFile(destination, []byte(content), 0777); err != nil {
+		return err
+	}
+
+	checksum := sha1.Sum([]byte(content))
+	d.SetId(hex.EncodeToString(checksum[:]))
+
+	return nil
+}
+
+func resourceLocalFileDelete(d *schema.ResourceData, _ interface{}) error {
+	os.Remove(d.Get("filename").(string))
+	return nil
+}

builtin/providers/local/resource_local_file_test.go

@@ -0,0 +1,56 @@
+package local
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	r "github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestLocalFile_Basic(t *testing.T) {
+	var cases = []struct {
+		path    string
+		content string
+		config  string
+	}{
+		{
+			"local_file",
+			"This is some content",
+			`resource "local_file" "file" {
+         content     = "This is some content"
+         filename    = "local_file"
+      }`,
+		},
+	}
+
+	for _, tt := range cases {
+		r.UnitTest(t, r.TestCase{
+			Providers: testProviders,
+			Steps: []r.TestStep{
+				{
+					Config: tt.config,
+					Check: func(s *terraform.State) error {
+						content, err := ioutil.ReadFile(tt.path)
+						if err != nil {
+							return fmt.Errorf("config:\n%s\n,got: %s\n", tt.config, err)
+						}
+						if string(content) != tt.content {
+							return fmt.Errorf("config:\n%s\ngot:\n%s\nwant:\n%s\n", tt.config, content, tt.content)
+						}
+						return nil
+					},
+				},
+			},
+			CheckDestroy: func(*terraform.State) error {
+				if _, err := os.Stat(tt.path); os.IsNotExist(err) {
+					return nil
+				}
+				return errors.New("local_file did not get destroyed")
+			},
+		})
+	}
+}

command/internal_plugin_list.go

@@ -39,6 +39,7 @@ import (
 	influxdbprovider "github.com/hashicorp/terraform/builtin/providers/influxdb"
 	kubernetesprovider "github.com/hashicorp/terraform/builtin/providers/kubernetes"
 	libratoprovider "github.com/hashicorp/terraform/builtin/providers/librato"
+	localprovider "github.com/hashicorp/terraform/builtin/providers/local"
 	logentriesprovider "github.com/hashicorp/terraform/builtin/providers/logentries"
 	mailgunprovider "github.com/hashicorp/terraform/builtin/providers/mailgun"
 	mysqlprovider "github.com/hashicorp/terraform/builtin/providers/mysql"
@@ -115,6 +116,7 @@ var InternalProviders = map[string]plugin.ProviderFunc{
 	"influxdb":     influxdbprovider.Provider,
 	"kubernetes":   kubernetesprovider.Provider,
 	"librato":      libratoprovider.Provider,
+	"local":        localprovider.Provider,
 	"logentries":   logentriesprovider.Provider,
 	"mailgun":      mailgunprovider.Provider,
 	"mysql":        mysqlprovider.Provider,

website/source/docs/providers/local/index.html.markdown

@@ -0,0 +1,19 @@
+---
+layout: "local"
+page_title: "Provider: Local"
+sidebar_current: "docs-local-index"
+description: |-
+  The Local provider is used to manage local resources (i.e. files).
+---
+
+# Local Provider
+
+The Local provider is used to manage local resources (i.e. files).
+
+Use the navigation to the left to read about the available resources.
+
+## Example Usage
+
+```
+provider "local" {}
+```

website/source/docs/providers/local/r/file.html.md

@@ -0,0 +1,30 @@
+---
+layout: "local"
+page_title: "Local: local_file"
+sidebar_current: "docs-local-resource-file"
+description: |-
+  Generates a local file from content.
+---
+
+# local\_file
+
+Generates a local file from a given content.
+
+## Example Usage
+
+```
+data "local_file" "foo" {
+    content     = "foo!"
+    filename = "${path.module}/foo.bar"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `content` - (required) The content of file to create.
+
+* `filename` - (required) The path of the file to create.
+
+NOTE: Any required parent folders are created automatically. Additionally, any existing file will get overwritten.

website/source/layouts/docs.erb

@@ -304,6 +304,10 @@
             <a href="/docs/providers/librato/index.html">Librato</a>
           </li>
 
+          <li<%= sidebar_current("docs-providers-local") %>>
+            <a href="/docs/providers/local/index.html">Local</a>
+          </li>
+
           <li<%= sidebar_current("docs-providers-logentries") %>>
             <a href="/docs/providers/logentries/index.html">Logentries</a>
           </li>

website/source/layouts/local.erb

@@ -0,0 +1,24 @@
+<% wrap_layout :inner do %>
+  <% content_for :sidebar do %>
+    <ul class="nav docs-sidenav">
+      <li<%= sidebar_current("docs-home") %>>
+        <a href="/docs/providers/index.html">All Providers</a>
+      </li>
+
+      <li<%= sidebar_current("docs-local-index") %>>
+        <a href="/docs/providers/local/index.html">Local Provider</a>
+      </li>
+
+      <li<%= sidebar_current("docs-local-resource") %>>
+        <a href="#">Resources</a>
+        <ul class="nav nav-visible">
+          <li<%= sidebar_current("docs-local-resource-file") %>>
+            <a href="/docs/providers/local/r/file.html">file</a>
+          </li>
+        </ul>
+      </li>
+    </ul>
+  <% end %>
+
+  <%= yield %>
+  <% end %>