View Source HXL (hxl v0.2.1)
HXL
An Elixir implementation of HCL
features
Features
- Decode from string or file
- Aims to be fully compliant with the HCL specification
- Function & variables support during evaluation
example-usage
Example Usage
hcl = """
resource "upcloud_server" "server1" {
hostname = "terraform.example.com"
zone = "nl-ams1"
plan = "1xCPU-1GB"
template {
size = 25
storage = "01000000-0000-4000-8000-000030200200"
}
network_interface {
type = "public"
}
login {
user = "root"
keys = [
"ssh-rsa public key",
]
create_password = true
password_delivery = "email"
}
connection {
host = "127.0.0.2"
type = "ssh"
user = "root"
private_key = file("~/.ssh/rsa_private_key")
}
provisioner "remote-exec" {
inline = [
"echo 'Hello world!'"
]
}
}
"""
{:ok, config_file} = HXL.decode(hcl, functions: %{"file" => &File.read/1})
from-file
From file
{:ok, config_file} = HXL.decode_file("/path/to/file")
as-ast
As ast
hcl = """
service "http" {
a = 1
b = 2
}
"""
{:ok %HXL.Body{}} = HXL.decode_as_ast(hcl)
installation
Installation
Add hxl to your list of dependencies in mix.exs:
def deps do
[
{:hxl, "~> 0.1.0"}
]
end
hcl-syntax-specification
HCL Syntax Specification
lexical-elements
Lexical Elements
- [x] Comments
- [x] Identifiers
- [x] Operators & delimiters
- [x] Numeric literals
structural-language
Structural Language
- [x] Body
- [x] Attributes
- [x] Blocks
- [x] One-line blocks
expression-language
Expression language
- [x] Expressions
- [x] Expr term
- [x] Literal Value
- [x] Collection Value
- [x] Template Expr
- [x] Variable Expr
- [x] Function Call
- [x] For Expr
- [x] ExprTerm Index
- [x] ExprTerm GetAttr
- [x] ExprTerm Splat
- [x] "(" Expression ")"
- [x] Operation
- [x] Conditional
- [x] Expr term
template-language
Template Language
- [] TemplateLiteral
- [] TemplateInterpolation
- [] TemplateDirective
representations
Representations
- [x] HCL Native syntax
- [ ] JSON
Link to this section Summary
Link to this section Types
Link to this section Functions
Decode a binary to a HCL document.
decode/2 parses and evaluates the AST before returning the HCL docuement.
If the document is using functions in it's definition, these needs to be passed in the opts part of this functions.
See bellow for an example
options
Options
The following options can be passed to configure evaluation of the document:
:evaluator- AHXL.Evaluatormodule to interpret the AST during evaluation. SeeHXL.Evaluatorfor more information.:functions- A map of(<function_name> -> <function>)to make available in document evaluation.:variables- A map of Top level variables that should be injected into the context when evaluating the document.:keys- controls how keys in the parsed AST are evaluated. Possible values are::strings(default) - evaluates keys as strings:atoms- converts keys to atoms withString.to_atom/1:atoms!- converts keys to atoms withString.to_existing_atom/1(key -> term)- converts keys using the provided function
examples
Examples
Using functions:
iex> hcl = "a = upper(trim(" a "))"
"a = upper(trim(" a "))"
iex> HXL.decode(hcl, functions: %{"upper" => &String.capitalize/1, "trim" => &String.trim/1})
{:ok, %{"a" => "A"}}Using variables:
iex> hcl = "a = b"
"a = b"
iex> HXL.decode(hcl, variables: %{"b" => "B"})
{:ok, %{"a" => "B"}}Reads a HCL document from a binary. Returns the document or raises HXL.Error.
See from_binary/1
Decode a binary to a HXL document AST.
examples
Examples
iex> HXL.decode_as_ast("a = 1")
{:ok, %HXL.Ast.Body{
statements: [
%HXL.Ast.Attr{
expr: %HXL.Ast.Literal{value: {:int, 1}}, name: "a"}
]
}}Reads a HCL document from file.
Uses same options as decode/2
examples
Examples
iex> HXL.decode_file("/path/to/file.hcl")
{:ok, %{"a" => "b"}}Reads a HCL document from file, returns the document directly or raises HXL.Error.
See decode_file/1