Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52
This commit is contained in:
Valerio Gheri
2017-03-31 18:01:58 +02:00
parent 024c5a4e4e
commit c40779224f
2037 changed files with 831329 additions and 1854 deletions

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theme: jekyll-theme-slate

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# Type Conversion Functions
The following type conversion functions are provided by Sprig:
- `atoi`: Convert a string to an integer
- `float64`: Convert to a float64
- `int`: Convert to an `int` at the system's width.
- `int64`: Convert to an `int64`
- `toString`: Convert to a string
- `toStrings`: Convert a list, slice, or array to a list of strings.
Only `atoi` requires that the input be a specific type. The others will attempt
to convert from any type to the destination type. For example, `int64` can convert
floats to ints, and it can also convert strings to ints.
## toStrings
Given a list-like collection, produce a slice of strings.
```
list 1 2 3 | toStrings
```
The above converts `1` to `"1"`, `2` to `"2"`, and so on, and then returns
them as a list.

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# Cryptographic and Security Functions
Sprig provides a couple of advanced cryptographic functions.
## sha256sum
The `sha256sum` function receives a string, and computes it's SHA256 digest.
```
sha256sum "Hello world!"
```
The above will compute the SHA 256 sum in an "ASCII armored" format that is
safe to print.
## derivePassword
The `derivePassword` function can be used to derive a specific password based on
some shared "master password" constraints. The algorithm for this is
[well specified](http://masterpasswordapp.com/algorithm.html).
```
derivePassword 1 "long" "password" "user" "example.com"
```
Note that it is considered insecure to store the parts directly in the template.
## generatePrivateKey
The `generatePrivateKey` function generates a new private key encoded into a PEM
block.
It takes one of the values for its first param:
- `ecdsa`: Generate an elyptical curve DSA key (P256)
- `dsa`: Generate a DSA key (L2048N256)
- `rsa`: Generate an RSA 4096 key

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# Date Functions
## now
The current date/time. Use this in conjunction with other date functions.
## date
The `date` function formats a date.
Format the date to YEAR-MONTH-DAY:
```
now | date "2006-01-02"
```
Date formatting in Go is a [little bit different](https://pauladamsmith.com/blog/2011/05/go_time.html).
In short, take this as the base date:
```
Mon Jan 2 15:04:05 MST 2006
```
Write it in the format you want. Above, `2006-01-02` is the same date, but
in the format we want.
## dateInZone
Same as `date`, but with a timezone.
```
date "2006-01-02" (now) "UTC"
```
## dateModify
The `dateModify` takes a modification and a date and returns the timestamp.
Subtract an hour and thirty minutes from the current time:
```
now | date_modify "-1.5h"
```
## htmlDate
The `htmlDate` function formates a date for inserting into an HTML date picker
input field.
```
now | htmlDate
```
## htmlDateInZone
Same as htmlDate, but with a timezone.
```
htmlDate (now) "UTC"
```

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# Default Functions
Sprig provides tools for setting default values for templates.
## default
To set a simple default value, use `default`:
```
default "foo" .Bar
```
In the above, if `.Bar` evaluates to a non-empty value, it will be used. But if
it is empty, `foo` will be returned instead.
The definition of "empty" depends on type:
- Numeric: 0
- String: ""
- Lists: `[]`
- Dicts: `{}`
- Boolean: `false`
- And always `nil` (aka null)
For structs, there is no definition of empty, so a struct will never return the
default.
## empty
The `empty` function returns `true` if the given value is considered empty, and
`false` otherwise. The empty values are listed in the `default` section.
```
empty .Foo
```
Note that in Go template conditionals, emptiness is calculated for you. Thus,
you rarely need `if empty .Foo`. Instead, just use `if .Foo`.
## coalesce
The `coalesce` function takes a list of values and returns the first non-empty
one.
```
coalesce 0 1 2
```
The above returns `1`.
This function is useful for scanning through multiple variables or values:
```
coalesce .name .parent.name "Matt"
```
The above will first check to see if `.name` is empty. If it is not, it will return
that value. If it _is_ empty, `coalesce` will evaluate `.parent.name` for emptiness.
Finally, if both `.name` and `.parent.name` are empty, it will return `Matt`.

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# Dictionaries and Dict Functions
Sprig provides a key/value storage type called a `dict` (short for "dictionary",
as in Python). A `dict` is an _unorder_ type.
The key to a dictionary **must be a string**. However, the value can be any
type, even another `dict` or `list`.
Unlike `list`s, `dict`s are not immutable. The `set` and `unset` functions will
modify the contents of a dictionary.
## dict
Creating dictionaries is done by calling the `dict` function and passing it a
list of pairs.
The following creates a dictionary with three items:
```
$myDict := dict "name1" "value1" "name2" "value2" "name3" "value 3"
```
## set
Use `set` to add a new key/value pair to a dictionary.
```
$_ := set $myDict "name4" "value4"
```
Note that `set` _returns the dictionary_ (a requirement of Go template functions),
so you may need to trap the value as done above with the `$_` assignment.
## unset
Given a map and a key, delete the key from the map.
```
$_ := unset $myDict "name4"
```
As with `set`, this returns the dictionary.
Note that if the key is not found, this operation will simply return. No error
will be generated.
## hasKey
The `hasKey` function returns `true` if the given dict contains the given key.
```
hasKey $myDict "name1"
```
If the key is not found, this returns `false`.
## pluck
The `pluck` function makes it possible to give one key and multiple maps, and
get a list of all of the matches:
```
pluck "name1" $myDict $myOtherDict
```
The above will return a `list` containing every found value (`[value1 otherValue1]`).
If the give key is _not found_ in a map, that map will not have an item in the
list (and the length of the returned list will be less than the number of dicts
in the call to `pluck`.
If the key is _found_ but the value is an empty value, that value will be
inserted.
A common idiom in Sprig templates is to uses `pluck... | first` to get the first
matching key out of a collection of dictionaries.
## keys
The `keys` function will return a `list` of all of the keys in a `dict`. Since
a dictionary is _unordered_, the keys will not be in a predictable order. They
can be sorted with `sortAlpha`.
```
keys $myDict | sortAlpha
```
## pick
The `pick` function selects just the given keys out of a dictionary, creating a
new `dict`.
```
$new := pick $myDict "name1" "name3"
```
The above returns `{name1: value1, name2: value2}`
## omit
The `omit` function is similar to `pick`, except it returns a new `dict` with all
the keys that _do not_ match the given keys.
```
$new := omit $myDict "name1" "name3"
```
The above returns `{name2: value2}`
## A Note on Dict Internals
A `dict` is implemented in Go as a `map[string]interface{}`. Go developers can
pass `map[string]interface{}` values into the context to make them available
to templates as `dict`s.

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# Encoding Functions
Sprig has the following encoding and decoding functions:
- `b64enc`/`b64dec`: Encode or decode with Base64
- `b32enc`/`b32dec`: Encode or decode with Base32

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# Sprig Function Documentation
The Sprig library provides over 70 template functions for Go's template language.
- [String Functions](strings.html): `trim`, `wrap`, `randAlpha`, `plural`, etc.
- [String List Functions](string_slice.html): `splitList`, `sortAlpha`, etc.
- [Math Functions](math.html): `add`, `max`, `mul`, etc.
- [Integer Slice Functions](integer_slice.html): `until`, `untilStep`
- [Date Functions](date.html): `now`, `date`, etc.
- [Defaults Functions](defaults.html): `default`, `empty`, `coalesce`
- [Encoding Functions](encoding.html): `b64enc`, `b64dec`, etc.
- [Lists and List Functions](lists.html): `list`, `first`, `uniq`, etc.
- [Dictionaries and Dict Functions](dicts.html): `dict`, `hasKey`, `pluck`, etc.
- [Type Conversion Functions](conversion.html): `atoi`, `int64`, `toString`, etc.
- [File Path Functions](paths.html): `base`, `dir`, `ext`, `clean`, `isAbs`
- Advanced Functions
- [UUID Functions](uuid.html): `uuidv4`
- [OS Functions](os.html): `env`, `expandenv`
- [Version Comparison Functions](semver.html): `semver`, `semverCompare`
- [Reflection](reflection.html): `typeOf`, `kindIs`, `typeIsLike`, etc.
- [Cryptographic and Security Functions](crypto.html): `derivePassword`, `sha256sum`, `genPrivateKey`

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# Integer Slice Functions
## until
The `until` function builds a range of integers.
```
until 5
```
The above generates the list `[0, 1, 2, 3, 4]`.
This is useful for looping with `range $i, $e := until 5`.
## untilStep
Like `until`, `untilStep` generates a list of counting integers. But it allows
you to define a start, stop, and step:
```
untilStep 3 6 2
```
The above will produce `[3 5]` by starting with 3, and adding 2 until it is equal
or greater than 6. This is similar to Python's `range` function.

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# Lists and List Functions
Sprig provides a simple `list` type that can contain arbitrary sequential lists
of data. This is similar to arrays or slices, but lists are designed to be used
as immutable data types.
Create a list of integers:
```
$myList := list 1 2 3 4 5
```
The above creates a list of `[1 2 3 4 5]`.
## first
To get the head item on a list, use `first`.
`first $myList` returns `1`
## rest
To get the tail of the list (everything but the first item), use `rest`.
`rest $myList` returns `[2 3 4 5]`
## last
To get the last item on a list, use `last`:
`last $myList` returns `5`. This is roughly analogous to reversing a list and
then calling `first`.
## initial
This compliments `last` by returning all _but_ the last element.
`initial $myList` returns `[1 2 3 4]`.
## append
Append a new item to an existing list, creating a new list.
```
$new = append $myList 6
```
The above would set `$new` to `[1 2 3 4 5 6]`. `$myList` would remain unaltered.
## prepend
Push an alement onto the front of a list, creating a new list.
```
prepend $myList 0
```
The above would produce `[0 1 2 3 4 5]`. `$myList` would remain unaltered.
## reverse
Produce a new list with the reversed elements of the given list.
```
reverse $myList
```
The above would generate the list `[5 4 3 2 1]`.
## uniq
Generate a list with all of the duplicates removed.
```
list 1 1 1 2 | uniq
```
The above would produce `[1 2]`
## without
The `without` function filters items out of a list.
```
without $myList 3
```
The above would produce `[1 2 4 5]`
Without can take more than one filter:
```
without $myList 1 3 5
```
That would produce `[2 4]`
## has
Test to see if a list has a particular element.
```
has $myList 4
```
The above would return `true`, while `has $myList "hello"` would return false.
## A Note on List Internals
A list is implemented in Go as a `[]interface{}`. For Go developers embedding
Sprig, you may pass `[]interface{}` items into your template context and be
able to use all of the `list` functions on those items.

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# Math Functions
All math functions operate on `int64` values unless specified otherwise.
(In the future, these will be extended to handle floats as well)
## add
Sum numbers with `add`
## add1
To increment by 1, use `add1`
## sub
To subtract, use `sub`
## div
Perform integer division with `div`
## mod
Modulo with `mod`
## mul
Multiply with `mul`
## max
Return the largest of a series of integers:
This will return `3`:
```
max 1 2 3
```
## min
Return the smallest of a series of integers.
`min 1 2 3` will return `1`.

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# OS Functions
_WARNING:_ These functions can lead to information leakage if not used
appropriately.
_WARNING:_ Some notable implementations of Sprig (such as
[Kubernetes Helm](http://helm.sh) _do not provide these functions for security
reasons_.
## env
The `env` function reads an environment variable:
```
env "HOME"
```
## expandenv
To substitute environment variables in a string, use `expandenv`:
```
expandenv "Your path is set to $PATH"
```

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# File Path Functions
While Sprig does not grant access to the filesystem, it does provide functions
for working with strings that follow file path conventions.
# base
Return the last element of a path.
```
base "foo/bar/baz"
```
The above prints "baz"
# dir
Return the directory, stripping the last part of the path. So `dir "foo/bar/baz"`
returns `foo/bar`
# clean
Clean up a path.
```
clean "foo/bar/../baz"
```
The above resolves the `..` and returns `foo/baz`
# ext
Return the file extension.
```
ext "foo.bar"
```
The above returns `.bar`.
# isAbs
To check whether a file path is absolute, use `isAbs`.

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# Reflection Functions
Sprig provides rudimentary reflection tools. These help advanced template
developers understand the underlying Go type information for a particular value.
Go has several primitive _kinds_, like `string`, `slice`, `int64`, and `bool`.
Go has an open _type_ system that allows developers to create their own types.
Sprig provides a set of functions for each.
## Kind Functions
There are two Kind functions: `kindOf` returns the kind of an object.
```
kindOf "hello"
```
The above would return `string`. For simple tests (like in `if` blocks), the
`isKind` function will let you verify that a value is a particular kind:
```
kindIs "int" 123
```
The above will return `true`
## Type Functions
Types are slightly harder to work with, so there are three different functions:
- `typeOf` returns the underlying type of a value: `typeOf $foo`
- `typeIs` is like `kindIs`, but for types: `typeIs "*io.Buffer" $myVal`
- `typeIsLike` works as `kindIs`, except that it also dereferences pointers.
**Note:** None of these can test whether or not something implements a given
interface, since doing so would require compiling the interface in ahead of time.

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# Semantic Version Functions
Some version schemes are easily parseable and comparable. Sprig provides functions
for working with [SemVer 2](http://semver.org) versions.
## semver
The `semver` function parses a string into a Semantic Version:
```
$version := semver "1.2.3-alpha.1+123"
```
_If the parser fails, it will cause template execution to halt with an error._
At this point, `$version` is a pointer to a `Version` object with the following
properties:
- `$version.Major`: The major number (`1` above)
- `$version.Minor`: The minor number (`2` above)
- `$version.Patch`: The patch number (`3` above)
- `$version.Prerelease`: The prerelease (`alpha.1` above)
- `$version.Metadata`: The build metadata (`123` above)
- `$version.Original`: The original version as a string
Additionally, you can compare a `Version` to another `version` using the `Compare`
function:
```
semver "1.4.3" | (semver "1.2.3").Compare
```
The above will return `-1`.
The return values are:
- `-1` if the given semver is greater than the semver whose `Compare` method was called
- `1` if the version who's `Compare` function was called is greater.
- `0` if they are the same version
(Note that in SemVer, the `Metadata` field is not compared during version
comparison operations.)
## semverCompare
A more robust comparison function is provided as `semverCompare`. This version
supports version ranges:
- `semverCompare "1.2.3" "1.2.3"` checks for an exact match
- `semverCompare "^1.2.0" "1.2.3"` checks that the major and minor versions match, and that the patch
number of the second version is _greater than or equal to_ the first parameter.
The SemVer functions use the [Masterminds semver library](https://github.com/Masterminds/semver),
from the creators of Sprig.
## Basic Comparisons
There are two elements to the comparisons. First, a comparison string is a list
of comma separated and comparisons. These are then separated by || separated or
comparisons. For example, `">= 1.2, < 3.0.0 || >= 4.2.3"` is looking for a
comparison that's greater than or equal to 1.2 and less than 3.0.0 or is
greater than or equal to 4.2.3.
The basic comparisons are:
* `=`: equal (aliased to no operator)
* `!=`: not equal
* `>`: greater than
* `<`: less than
* `>=`: greater than or equal to
* `<=`: less than or equal to
_Note, according to the Semantic Version specification pre-releases may not be
API compliant with their release counterpart. It says,_
> _A pre-release version indicates that the version is unstable and might not satisfy the intended compatibility requirements as denoted by its associated normal version._
_SemVer comparisons without a pre-release value will skip pre-release versions.
For example, `>1.2.3` will skip pre-releases when looking at a list of values
while `>1.2.3-alpha.1` will evaluate pre-releases._
## Hyphen Range Comparisons
There are multiple methods to handle ranges and the first is hyphens ranges.
These look like:
* `1.2 - 1.4.5` which is equivalent to `>= 1.2, <= 1.4.5`
* `2.3.4 - 4.5` which is equivalent to `>= 2.3.4, <= 4.5`
## Wildcards In Comparisons
The `x`, `X`, and `*` characters can be used as a wildcard character. This works
for all comparison operators. When used on the `=` operator it falls
back to the pack level comparison (see tilde below). For example,
* `1.2.x` is equivalent to `>= 1.2.0, < 1.3.0`
* `>= 1.2.x` is equivalent to `>= 1.2.0`
* `<= 2.x` is equivalent to `<= 3`
* `*` is equivalent to `>= 0.0.0`
## Tilde Range Comparisons (Patch)
The tilde (`~`) comparison operator is for patch level ranges when a minor
version is specified and major level changes when the minor number is missing.
For example,
* `~1.2.3` is equivalent to `>= 1.2.3, < 1.3.0`
* `~1` is equivalent to `>= 1, < 2`
* `~2.3` is equivalent to `>= 2.3, < 2.4`
* `~1.2.x` is equivalent to `>= 1.2.0, < 1.3.0`
* `~1.x` is equivalent to `>= 1, < 2`
## Caret Range Comparisons (Major)
The caret (`^`) comparison operator is for major level changes. This is useful
when comparisons of API versions as a major change is API breaking. For example,
* `^1.2.3` is equivalent to `>= 1.2.3, < 2.0.0`
* `^1.2.x` is equivalent to `>= 1.2.0, < 2.0.0`
* `^2.3` is equivalent to `>= 2.3, < 3`
* `^2.x` is equivalent to `>= 2.0.0, < 3`

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# String Slice Functions
These function operate on or generate slices of strings. In Go, a slice is a
growable array. In Sprig, it's a special case of a `list`.
## join
Join a list of strings into a single string, with the given separator.
```
list "hello" "world" | join "_"
```
The above will produce `hello_world`
`join` will try to convert non-strings to a string value:
```
list 1 2 3 | join "+"
```
The above will produce `1+2+3`
## splitList and split
Split a string into a list of strings:
```
splitList "$" "foo$bar$baz"
```
The above will return `[foo bar baz]`
The older `split` function splits a string into a `dict`. It is designed to make
it easy to use template dot notation for accessing members:
```
$a := split "$" "foo$bar$baz"
```
The above produces a map with index keys. `{_0: foo, _1: bar, _2: baz}`
```
$a._0
```
The above produces `foo`
## sortAlpha
The `sortAlpha` function sorts a list of strings into alphabetical (lexicographical)
order.
It does _not_ sort in place, but returns a sorted copy of the list, in keeping
with the immutability of lists.

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# String Functions
Sprig has a number of string manipulation functions.
## trim
The `trim` function removes space from either side of a string:
```
trim " hello "
```
The above produces `hello`
## trimAll
Remove given characters from the front or back of a string:
```
trimAll "$" "$5.00"
```
The above returns `5.00` (as a string).
## trimSuffix
Trim just the suffix from a string:
```
trimSuffix "-" "hello-"
```
The above returns `hello`
## upper
Convert the entire string to uppercase:
```
upper "hello"
```
The above returns `HELLO`
## lower
Convert the entire string to lowercase:
```
lower "HELLO"
```
The above returns `hello`
## title
Convert to title case:
```
title "hello world"
```
The above returns `Hello World`
## untitle
Remove title casing. `untitle "Hello World"` produces `hello world`.
## repeat
Repeat a string multiple times:
```
repeat 3 "hello"
```
The above returns `hellohellohello`
## substr
Get a substring from a string. It takes three parameters:
- start (int)
- length (int)
- string (string)
```
substr 0 5 "hello world"
```
The above returns `hello`
## nospace
Remove all whitespace from a string.
```
nospace "hello w o r l d"
```
The above returns `helloworld`
## trunc
Truncate a string (and add no suffix)
```
trunc 5 "hello world"
```
The above produces `hello`.
## abbrev
Truncate a string with ellipses (`...`)
Parameters:
- max length
- the string
```
abbrev 5 "hello world"
```
The above returns `he...`, since it counts the width of the ellipses against the
maximum length.
## abbrevboth
Abbreviate both sides:
```
abbrevboth 5 10 "1234 5678 9123"
```
the above produces `...5678...`
It takes:
- left offset
- max length
- the string
## initials
Given multiple words, take the first letter of each word and combine.
```
initials "First Try"
```
The above returns `FT`
## randAlphaNum, randAlpha, randNumeric, and randAscii
These four functions generate random strings, but with different base character
sets:
- `randAlphaNum` uses `0-9a-zA-Z`
- `randAlpha` uses `a-zA-Z`
- `randNumeric` uses `0-9`
- `randAscii` uses all printable ASCII characters
Each of them takes one parameter: the integer length of the string.
```
randNumeric 3
```
The above will produce a random string with three digits.
## wrap
Wrap text at a given column count:
```
wrap 80 $someText
```
The above will wrap the string in `$someText` at 80 columns.
## wrapWith
`wrapWith` works as `wrap`, but lets you specify the string to wrap with.
(`wrap` uses `\n`)
```
wrapWith 5 "\t" "Hello World"
```
The above produces `hello world` (where the whitespace is an ASCII tab
character)
## contains
Test to see if one string is contained inside of another:
```
contains "cat" "catch"
```
The above returns `true` because `catch` contains `cat`.
## hasPrefix and hasSuffix
The `hasPrefix` and `hasSuffix` functions test whether a string has a given
prefix or suffix:
```
hasPrefix "cat" "catch"
```
The above returns `true` because `catch` has the prefix `cat`.
## quote and squote
These functions wrap a string in double quotes (`quote`) or single quotes
(`squote`).
## cat
The `cat` function concatenates multiple strings together into one, separating
them with spaces:
```
cat "hello" "beautiful" "world"
```
The above produces `hello beautiful world`
## indent
The `indent` function indents every line in a given string to the specified
indent width. This is useful when aligning multi-line strings:
```
indent 4 $lots_of_text
```
The above will indent every line of text by 4 space characters.
## replace
Perform simple string replacement.
It takes three arguments:
- string to replace
- string to replace with
- source string
```
"I Am Henry VIII" | replace " " "-"
```
The above will produce `I-Am-Henry-VIII`
## plural
Pluralize a string.
```
len $fish | plural "one anchovy" "many anchovies"
```
In the above, if the length of the string is 1, the first argument will be
printed (`one anchovy`). Otherwise, the second argument will be printed
(`many anchovies`).
The arguments are:
- singular string
- plural string
- length integer
NOTE: Sprig does not currently support languages with more complex pluralization
rules. And `0` is considered a plural because the English language treats it
as such (`zero anchovies`). The Sprig developers are working on a solution for
better internationalization.
## See Also...
The [Conversion Functions](conversion.html) contain functions for converting
strings. The [String Slice Functions](string_slice.html) contains functions
for working with an array of strings.

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# UUID Functions
Sprig can generate UUID v4 universally unique IDs.
```
uuidv4
```
The above returns a new UUID of the v4 (randomly generated) type.