This slide deck describes how we relied on a modified version of the standard `text/template` package to support arbitrary data transformations.

1. Abusing text/template
Arnaud Porterie - @icecrime - dotGo 2015

2. How can I get visibility into
my open source projects?

3. Collect
Store
Draw
Profit?

4. Filter
Rename
Enrich
Transform
1 {
2 "url": "https://api.github.com/repos/docker/docker/pulls/16603",
3 "id": 46083503,
4 "html_url": "https://github.com/docker/docker/pull/16603",
5 "diff_url": "https://github.com/docker/docker/pull/16603.diff",
6 "patch_url": "https://github.com/docker/docker/pull/16603.patch",
7 "issue_url": "https://api.github.com/repos/docker/docker/issues/16603",
8 "number": 16603,
9 "state": "closed",
10 "locked": false,
11 "title": "Add @vdemeester to MAINTAINERS",
12 "user": {
13 "login": "icecrime",
14 "id": 1564054,
15 "avatar_url": "https://avatars.githubusercontent.com/u/1564054?v=3",
16 "gravatar_id": "",
17 "url": "https://api.github.com/users/icecrime",
18 "html_url": "https://github.com/icecrime",
19 "followers_url": "https://api.github.com/users/icecrime/followers",
20 "following_url": "https://api.github.com/users/icecrime/following{/other_user}",
21 "gists_url": "https://api.github.com/users/icecrime/gists{/gist_id}",
22 "starred_url": "https://api.github.com/users/icecrime/starred{/owner}{/repo}",
23 "subscriptions_url": "https://api.github.com/users/icecrime/subscriptions",
24 "organizations_url": "https://api.github.com/users/icecrime/orgs",
25 "repos_url": "https://api.github.com/users/icecrime/repos",
26 "events_url": "https://api.github.com/users/icecrime/events{/privacy}",
27 "received_events_url": "https://api.github.com/users/icecrime/received_events",
28 "type": "User",
29 "site_admin": false
30 },
31 "body": ":tada:",
32 "created_at": "2015-09-26T15:16:23Z",
33 "updated_at": "2015-09-27T21:02:55Z",
34 "closed_at": "2015-09-27T19:14:39Z",
35 "merged_at": "2015-09-27T19:14:39Z",
36 "merge_commit_sha": "7fae194c5b4c694dc45a385866207df6bea57e61",
~~ ...
320 }

5. 1 {
2 "url": "https://api.github.com/repos/docker/docker/pulls/16603",
3 "id": 46083503,
4 "html_url": "https://github.com/docker/docker/pull/16603",
5 "diff_url": "https://github.com/docker/docker/pull/16603.diff",
6 "patch_url": "https://github.com/docker/docker/pull/16603.patch",
7 "issue_url": "https://api.github.com/repos/docker/docker/issues/16603",
8 "number": 16603,
9 "state": "closed",
10 "locked": false,
11 "title": "Add @vdemeester to MAINTAINERS",
12 "user": {
13 "login": "icecrime",
14 "id": 1564054,
15 "avatar_url": "https://avatars.githubusercontent.com/u/1564054?v=3",
16 "gravatar_id": "",
17 "url": "https://api.github.com/users/icecrime",
18 "html_url": "https://github.com/icecrime",
19 "followers_url": "https://api.github.com/users/icecrime/followers",
20 "following_url": "https://api.github.com/users/icecrime/following{/other_user}",
21 "gists_url": "https://api.github.com/users/icecrime/gists{/gist_id}",
22 "starred_url": "https://api.github.com/users/icecrime/starred{/owner}{/repo}",
23 "subscriptions_url": "https://api.github.com/users/icecrime/subscriptions",
24 "organizations_url": "https://api.github.com/users/icecrime/orgs",
25 "repos_url": "https://api.github.com/users/icecrime/repos",
26 "events_url": "https://api.github.com/users/icecrime/events{/privacy}",
27 "received_events_url": "https://api.github.com/users/icecrime/received_events",
28 "type": "User",
29 "site_admin": false
30 },
31 "body": ":tada:",
32 "created_at": "2015-09-26T15:16:23Z",
33 "updated_at": "2015-09-27T21:02:55Z",
34 "closed_at": "2015-09-27T19:14:39Z",
35 "merged_at": "2015-09-27T19:14:39Z",
36 "merge_commit_sha": "7fae194c5b4c694dc45a385866207df6bea57e61",
~~ ...
320 }
{
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}

6. "Hello dotGo!"
package main
import (
"os"
"text/template"
)
type Foo struct {
Bar string
}
type Something struct {
Foo Foo
}
const text = "Hello {{ .Foo.Bar }}!"
func main() {
obj := Something{
Foo{
Bar: "dotGo",
},
}
t, _ := template.New("").Parse(text)
t.Execute(os.Stdout, obj)
}

7. What if we...
● Fork text/template
● Substitute fmt.Fprint for a return
● Use the template syntax as a DSL for data transformation
● Describe the model in a TOML configuration file

8. {
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}
[transformations.pull_request]
author = "{{ user_data .user.login }}"
body = "{{ .body }}"
closed_at = "{{ .closed_at }}"
created_at = "{{ .created_at }}"
labels = "{{ range .labels }}{{ .name }}{{ end }}"
merged = "{{ .merged }}"
ms = "{{ if $m := .milestone }}{{ $m.title }}{{ end }}"
number = "{{ .number }}"
state = "{{ .state }}"
title = "{{ .title }}"

9. [transformations.pull_request]
author = "{{ user_data .user.login }}"
body = "{{ .body }}"
closed_at = "{{ .closed_at }}"
created_at = "{{ .created_at }}"
labels = "{{ range .labels }}{{ .name }}{{ end }}"
merged = "{{ .merged }}"
ms = "{{ if $m := .milestone }}{{ $m.title }}{{ end }}"
number = "{{ .number }}"
state = "{{ .state }}"
title = "{{ .title }}"
{
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}
Simple mapping

10. [transformations.pull_request]
author = "{{ user_data .user.login }}"
body = "{{ .body }}"
closed_at = "{{ .closed_at }}"
created_at = "{{ .created_at }}"
labels = "{{ range .labels }}{{ .name }}{{ end }}"
merged = "{{ .merged }}"
ms = "{{ if $m := .milestone }}{{ $m.title }}{{ end }}"
number = "{{ .number }}"
state = "{{ .state }}"
title = "{{ .title }}"
{
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}
Tests

11. [transformations.pull_request]
author = "{{ user_data .user.login }}"
body = "{{ .body }}"
closed_at = "{{ .closed_at }}"
created_at = "{{ .created_at }}"
labels = "{{ range .labels }}{{ .name }}{{ end }}"
merged = "{{ .merged }}"
ms = "{{ if $m := .milestone }}{{ $m.title }}{{ end }}"
number = "{{ .number }}"
state = "{{ .state }}"
title = "{{ .title }}"
{
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}
Loops

12. [transformations.pull_request]
author = "{{ user_data .user.login }}"
body = "{{ .body }}"
closed_at = "{{ .closed_at }}"
created_at = "{{ .created_at }}"
labels = "{{ range .labels }}{{ .name }}{{ end }}"
merged = "{{ .merged }}"
ms = "{{ if $m := .milestone }}{{ $m.title }}{{ end }}"
number = "{{ .number }}"
state = "{{ .state }}"
title = "{{ .title }}"
{
"author": {
"login": "icecrime",
"company": "Docker",
"is_maintainer": true
},
"body": ":tada:",
"closed_at": "2015-09-27T19:14:39Z",
"created_at": "2015-09-26T15:16:23Z",
"labels": ["status/4-merge"],
"merged": true,
"ms": "1.9.0",
"number": 16603,
"state": "closed",
"title": "Add @vdemeester...",
}
User defined functions

13. TOML
JSON

15. Profit!
Thank you
Arnaud Porterie - @icecrime
/icecrime/vossibility-collector