go-envtmpl

envtmpl

Executes text templates using data from environment variables and sends the result to STDOUT.

Usage:

envtmpl tmplDir tmplName.tmpl

Parse tmplDir/*.tmpl and renders tmplName.tmpl to STDOUT using environment variables.

envtmpl tmplDir/tmplName.tmpl

Parse tmplDir/*.tmpl and renders tmplName.tmpl to STDOUT using environment variables.

envtmpl -

Read template from STDIN and render to STDOUT using environment variables.

Flags

• -dl '{{' Left-hand action delimiter.
• -dr '}}' Right-hand action delimiter.

Exit codes

• 0 - OK.
• 1 - Usage.
• 2 - Template parse error.
• 3 - Template execution error.

Template Syntax.

See http://golang.org/pkg/text/template/ for template syntax.

See http://code.google.com/p/re2/wiki/Syntax for regular expression syntax.

Template Functions

In addition to the actions and functions provided by the core template engine, envtmpl provides the following functions for use in your templates:

• base32Decode - Decodes a base32 string.
• base32Encode - Encodes a value to base32.
• base64Decode - Decodes a base64 string.
• base64Encode - Encodes a value to base64.
• file - Read the contents of a file.
• get - Get a value from the global data store.
• hash - Calculate the hex encoded hash of a string.
• hexDecode - Decodes a hex string.
• hexEncode - Encodes a value to hex.
• include - Include a template.
• jsonDecode - Decodes a JSON string.
• jsonEncode - Encodes a value to JSON.
• linePrefix - Prefix each line.
• lower - Convert to lower case.
• regexReplace - Replace values using a regular expression.
• set - Set a value in the global data store.
• slice - Construct a substring from a string.
• slugify - Transform text to a slugified version.
• split - Split in a string substrings using another string.
• title - Convert to title case.
• trimPrefix - Remove leading prefix.
• trimSpace - Remove all leading and trailing white space.
• trimSuffix - Remove trailing suffix.
• upper - Convert to upper case.
• url - Parse a URL from a string.
• urlEscape - Escapes the string so it can be safely placed inside a URL query.
• urlUnescape - Unescapes a URL query string value.
• uuid - Create a random (v4) UUID.
• wordWrap - Wraps text to a given number of runes.

base32Decode

Decodes a base32 string.

Template:

{{ "JBSWY3DPEBLU6USMIQQQ====" | base32Decode }}

Output:

Hello WORLD!

base32Encode

Encodes a value to base32.

Template:

{{ "Hello WORLD!" | base32Encode }}

Output:

JBSWY3DPEBLU6USMIQQQ====

base64Decode

Decodes a base64 string.

Template:

{{ "SGVsbG8gV09STEQh" | base64Decode }}

Output:

Hello WORLD!

base64Encode

Encodes a value to base64.

Template:

{{ "Hello WORLD!" | base64Encode }}

Output:

SGVsbG8gV09STEQh

file

Read the contents of a file.

Template:

{{ file "../example/hello.txt" }}

Output:

Hello, 世界

get

Get a value from the global data store.

Template:

{{ define "t1" }}[{{ get "key" }}]{{ end }}
{{ set "key" "value" }}{{ template "t1" }}

Output:

[value]

hash

Calculate the hex encoded hash of a string. You can optionally specify a key to produce a HMAC string. The following hash algorithms are supported: adler32, crc32, crc64ecma, crc64iso, fnv1-32, fnv1-64, fnv1a-32, fnv1a-64, md5, sha1, sha224, sha256, sha384, sha512.

Template:

{{ "Hello World!" | hash "adler32" }}
{{ "Hello World!" | hash "adler32" "a key" }}

Output:

1c49043e
052901bf

Template:

{{ "Hello World!" | hash "crc32" }}
{{ "Hello World!" | hash "crc32" "a key" }}

Output:

1c291ca3
478193aa

Template:

{{ "Hello World!" | hash "crc64ecma" }}
{{ "Hello World!" | hash "crc64ecma" "a key" }}

Output:

75045245c9ea6fe2
387589d9abc2595d

Template:

{{ "Hello World!" | hash "crc64iso" }}
{{ "Hello World!" | hash "crc64iso" "a key" }}

Output:

7db9cf17f71cd9ac
e349c05d90529684

Template:

{{ "Hello World!" | hash "fnv1-32" }}
{{ "Hello World!" | hash "fnv1-32" "a key" }}

Output:

12a9a41c
44d4e845

Template:

{{ "Hello World!" | hash "fnv1-64" }}
{{ "Hello World!" | hash "fnv1-64" "a key" }}

Output:

8e59dd02f68c387c
bbf3e38bba595be5

Template:

{{ "Hello World!" | hash "fnv1a-32" }}
{{ "Hello World!" | hash "fnv1a-32" "a key" }}

Output:

b1ea4872
17ef57fd

Template:

{{ "Hello World!" | hash "fnv1a-64" }}
{{ "Hello World!" | hash "fnv1a-64" "a key" }}

Output:

8c0ec8d1fb9e6e32
ee9b6cfc8ca44005

Template:

{{ "Hello World!" | hash "md5" }}
{{ "Hello World!" | hash "md5" "a key" }}

Output:

ed076287532e86365e841e92bfc50d8c
3997a224c5ed2b57cf179a38ec61f455

Template:

{{ "Hello World!" | hash "sha1" }}
{{ "Hello World!" | hash "sha1" "a key" }}

Output:

2ef7bde608ce5404e97d5f042f95f89f1c232871
edff5c450e50bbc39c684f96f9647a7b2a412c42

Template:

{{ "Hello World!" | hash "sha224" }}
{{ "Hello World!" | hash "sha224" "a key" }}

Output:

4575bb4ec129df6380cedde6d71217fe0536f8ffc4e18bca530a7a1b
e2ea9d5f84029e65ad0185986f817fa1677e6c9868bbb80aa69b3052

Template:

{{ "Hello World!" | hash "sha256" }}
{{ "Hello World!" | hash "sha256" "a key" }}

Output:

7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069
31f704a351e00973d2320c7b55eeeab0cd4e53a6b5d281b172596eaf69667cfa

Template:

{{ "Hello World!" | hash "sha384" }}
{{ "Hello World!" | hash "sha384" "a key" }}

Output:

bfd76c0ebbd006fee583410547c1887b0292be76d582d96c242d2a792723e3fd6fd061f9d5cfd13b8f961358e6adba4a
6a51e0a4ec0cdc6698bccc183dfcd877376c3860871781d705e62286be9fe4c7df14f6c8a6100919e0b84032dd672f5e

Template:

{{ "Hello World!" | hash "sha512" }}
{{ "Hello World!" | hash "sha512" "a key" }}

Output:

861844d6704e8573fec34d967e20bcfef3d424cf48be04e6dc08f2bd58c729743371015ead891cc3cf1c9d34b49264b510751b1ff9e537937bc46b5d6ff4ecc8
a22b0da52cc34b891eb7575afc4cc73189a0c770a039d6d4c28f3f5a45ea62fce3b73094b63338a32ef5d3c7a20f28331d5ea899c58b8cebdf21aa3469cf3731

hexDecode

Decodes a hex string.

Template:

{{ "48656c6c6f20574f524c4421" | hexDecode }}

Output:

Hello WORLD!

hexEncode

Encodes a value to hex.

Template:

{{ "Hello WORLD!" | hexEncode }}

Output:

48656c6c6f20574f524c4421

include

Include a template. Differs from the template keyword in that it can accept the template name as part of a pipeline.

Template:

{{define "ex"}}FOO is {{ .FOO }}{{end}}{{ $t := "ex" }}>>{{ include $t . }}<<

Output:

>>FOO is foo<<

jsonDecode

Decodes a JSON string.

Template:

{{ $j := "{\"foo\":\"bar\"}" | jsonDecode }}Foo is {{ $j.foo }}

Output:

Foo is bar

jsonEncode

Encodes a value to JSON.

Template:

{{ "Hello\n<WORLD>!" | jsonEncode }}

Output:

"Hello\n\u003cWORLD\u003e!"

Template:

{{ split "Hello\n<WORLD>!" "\n" | jsonEncode }}

Output:

[
  "Hello",
  "\u003cWORLD\u003e!"
]

linePrefix

Prefix each line.

Template:

{{ "line1\nline2\nline3" | linePrefix "- " }}

Output:

- line1
- line2
- line3

lower

Convert to lower case.

Template:

{{ "Hello WORLD!" | lower }}

Output:

hello world!

regexReplace

Replace values using a regular expression.

Template:

{{ "this is something" | regexReplace "(this) is " "[$1] was " }}

Output:

[this] was something

set

Set a value in the global data store.

Template:

{{ define "t1" }}[{{ get "key" }}]{{ end }}
{{ set "key" "value" }}{{ template "t1" }}

Output:

[value]

slice

Construct a substring from a string.

Template:

{{ "ᛁᚳ᛫ᛗᚨᚷ᛫ᚷᛚᚨᛋ᛫" | slice 3 7 }}

Output:

ᛗᚨᚷ᛫

slugify

Transform text to a slugified version. You can optionally specify a unicode normalization rule (NFC, NFD, NFKC, NFKD). Default is NFC.

Template:

 NFC: {{ "Hello áçćèńtš!" | slugify "NFC" }}
 NFD: {{ "Hello áçćèńtš!" | slugify "NFD" }}
NFKC: {{ "Hello áçćèńtš!" | slugify "NFKC" }}
NFKD: {{ "Hello áçćèńtš!" | slugify "NFKD" }}

Output:

 NFC: hello-áçćèńtš
 NFD: hello-accents
NFKC: hello-áçćèńtš
NFKD: hello-accents

Template:

{{ "Hello W/O-R_L~D!" | slugify }}

Output:

hello-wo-r_l~d

Template:

{{ "Hello WORLD!" | slugify }}

Output:

hello-world

split

Split in a string substrings using another string.

Template:

{{ range $k, $v := split "foo BAR bAz" " " }}{{ $k }}={{ $v }} {{ end }}

Output:

0=foo 1=BAR 2=bAz 

title

Convert to title case.

Template:

{{ "foo BAR bAz" | title }}

Output:

Foo BAR BAz

trimPrefix

Remove leading prefix. If the string doesn't start with the prefix then it's unchanged.

Template:

{{ "foo.bar" | trimPrefix "baz." }}

Output:

foo.bar

Template:

{{ "foo.bar" | trimPrefix "foo." }}

Output:

bar

trimSpace

Remove all leading and trailing white space.

Template:

{{ " \t\n foo bar \t\n " | trimSpace }}

Output:

foo bar

trimSuffix

Remove trailing suffix. If the string doesn't end with the suffix then it's unchanged.

Template:

{{ "foo.bar" | trimSuffix ".bar" }}

Output:

foo

Template:

{{ "foo.bar" | trimSuffix ".baz" }}

Output:

foo.bar

upper

Convert to upper case.

Template:

{{ "Hello World!" | upper }}

Output:

HELLO WORLD!

url

Parse a URL from a string. You can optionally provide a base URL that will be used as the context for processing.

Template:

{{define "u"}}Url: {{ . }}
IsAbs: {{ .IsAbs }}
Scheme: "{{ .Scheme }}"
Opaque: "{{ .Opaque }}"
UserPassword: "{{ .UserPassword }}"
Username: "{{ .Username }}"
HasPassword: {{ .HasPassword }}
Password: "{{ .Password }}"
Host: "{{ .Host }}"
Path: "{{ .Path }}"
RawQuery: "{{ .RawQuery }}"
Query: {{ .Query | jsonEncode }}
Fragment: "{{ .Fragment }}"
RequestURI: "{{ .RequestURI }}"
{{end}}
{{ template "u" "scheme://username:password@domain:port/path?query=string#fragment_id" | url }}
{{ template "u" "scheme://username:@domain?a=1&b=2&a=11" | url }}
{{ template "u" "scheme:opaque?query=string#fragment_id" | url }}
{{ template "u" "../bar/baz" | url }}
{{ template "u" "../bar/baz" | url "scheme://domain/foo/qux/" }}

Output:

Url: scheme://username:password@domain:port/path?query=string#fragment_id
IsAbs: true
Scheme: "scheme"
Opaque: ""
UserPassword: "username:password"
Username: "username"
HasPassword: true
Password: "password"
Host: "domain:port"
Path: "/path"
RawQuery: "query=string"
Query: {
  "query": [
    "string"
  ]
}
Fragment: "fragment_id"
RequestURI: "/path?query=string"

Url: scheme://username:@domain?a=1&b=2&a=11
IsAbs: true
Scheme: "scheme"
Opaque: ""
UserPassword: "username:"
Username: "username"
HasPassword: true
Password: ""
Host: "domain"
Path: ""
RawQuery: "a=1&b=2&a=11"
Query: {
  "a": [
    "1",
    "11"
  ],
  "b": [
    "2"
  ]
}
Fragment: ""
RequestURI: "/?a=1&b=2&a=11"

Url: scheme:opaque?query=string#fragment_id
IsAbs: true
Scheme: "scheme"
Opaque: "opaque"
UserPassword: ""
Username: ""
HasPassword: false
Password: ""
Host: ""
Path: ""
RawQuery: "query=string"
Query: {
  "query": [
    "string"
  ]
}
Fragment: "fragment_id"
RequestURI: "opaque?query=string"

Url: ../bar/baz
IsAbs: false
Scheme: ""
Opaque: ""
UserPassword: ""
Username: ""
HasPassword: false
Password: ""
Host: ""
Path: "../bar/baz"
RawQuery: ""
Query: {}
Fragment: ""
RequestURI: "../bar/baz"

Url: scheme://domain/foo/bar/baz
IsAbs: true
Scheme: "scheme"
Opaque: ""
UserPassword: ""
Username: ""
HasPassword: false
Password: ""
Host: "domain"
Path: "/foo/bar/baz"
RawQuery: ""
Query: {}
Fragment: ""
RequestURI: "/foo/bar/baz"

urlEscape

Escapes the string so it can be safely placed inside a URL query.

Template:

{{ "Hello World!" | urlEscape }}

Output:

Hello+World%21

urlUnescape

Unescapes a URL query string value.

Template:

{{ "Hello+World%21" | urlUnescape }}

Output:

Hello World!

uuid

Create a random (v4) UUID.

Template:

{{ uuid }}

Output:

50139f69-a54f-41c5-8c92-21c165c2eb2c

wordWrap

Wraps text to a given number of runes. Any existing white space is lost in the transformation.

Template:

{{ "The quick brown fox jumps over the lazy dog." | wordWrap 19 }}

Output:

The quick brown
fox jumps over the
lazy dog.

Template:

{{ "\t  The quick\nbrown fox jumps over the\n\t\tlazy dog." | wordWrap 19 }}

Output:

The quick brown
fox jumps over the
lazy dog.

Template:

{{ "Γαζέες καὶ μυρτιὲς δὲν θὰ βρῶ πιὰ στὸ χρυσαφὶ ξέφωτο" | wordWrap 19 }}

Output:

Γαζέες καὶ μυρτιὲς
δὲν θὰ βρῶ πιὰ στὸ
χρυσαφὶ ξέφωτο

Contributing

1. Fork the repository on GitHub
2. Create a named feature branch (i.e. add-new-feature)
3. Write your change
4. Submit a Pull Request

Authors

• William Bailey - @cowboysfromhell - (mail@williambailey.org.uk)

License

Licensed under a MIT license.