README
¶
tf-address
This package provides utilities for properly parsing Terraform addresses.
The parser is implemented using pigeon, a PEG implementation.
Addresses
Resource addresses are described by the Terraform documentation.
Identifiers are described in the Terraform Configuration Syntax document
Generating
If you change the peg, please regenerate the go code with:
go get -u github.com/mna/pigeon
go generate .
You may need to clean up the go.mod with:
go mod tidy
Examples
package main
import (
"fmt"
address "github.com/hashicorp/go-terraform-address"
)
func main() {
a, err := address.NewAddress(`module.first.module.second["xyz"].resource.name[2]`)
if err != nil {
panic(err)
}
fmt.Println(len(a.ModulePath)) // 2
fmt.Println(a.ModulePath[0].Name) // "first"
fmt.Println(a.ModulePath[1].Index.String()) // "xyz"
fmt.Printf("%T\n", a.ModulePath[1].Index.Value) // string
fmt.Println(a.ResourceSpec.Type) // "resource"
fmt.Println(a.ResourceSpec.Name) // "name"
fmt.Printf("%T\n", a.ResourceSpec.Index.Value) // int
}
Documentation
¶
Overview ¶
Package address contains logic for parsing a Terraform address.
The Terraform address grammar is documented at https://www.terraform.io/docs/internals/resource-addressing.html
Parsing is implemented using Pigeon, a PEG parser generator.
Index ¶
- func Parse(filename string, b []byte, opts ...Option) (interface{}, error)
- func ParseFile(filename string, opts ...Option) (i interface{}, err error)
- func ParseReader(filename string, r io.Reader, opts ...Option) (interface{}, error)
- type Address
- type Cloner
- type Index
- type Module
- type ModulePath
- type Option
- func AllowInvalidUTF8(b bool) Option
- func Debug(b bool) Option
- func Entrypoint(ruleName string) Option
- func GlobalStore(key string, value interface{}) Option
- func InitState(key string, value interface{}) Option
- func MaxExpressions(maxExprCnt uint64) Option
- func Memoize(b bool) Option
- func Recover(b bool) Option
- func Statistics(stats *Stats, choiceNoMatch string) Option
- type ResourceSpec
- type Stats
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Address ¶
type Address struct {
ModulePath ModulePath
ResourceSpec ResourceSpec
}
Address holds the parsed components of a Terraform address.
func NewAddress ¶
NewAddress parses the given address `a` into an Address struct. Returns an error if we find a malformed address. [module path][resource spec]
type Cloner ¶
type Cloner interface {
Clone() interface{}
}
Cloner is implemented by any value that has a Clone method, which returns a copy of the value. This is mainly used for types which are not passed by value (e.g map, slice, chan) or structs that contain such types.
This is used in conjunction with the global state feature to create proper copies of the state to allow the parser to properly restore the state in the case of backtracking.
type Index ¶
type Index struct {
Value interface{}
}
Index of either a module or a resource. Can either be an int or a string.
type Module ¶
type Module struct {
// Name of the module
Name string
// Index of the module. May be nil.
Index Index
}
Module represents a module component of an address. module.module_name[module index]
type ModulePath ¶
type ModulePath []Module
ModulePath holds a list of modules contained in the address. The furthest module on the left-hand side (outer-most) of the address is at index 0.
func (ModulePath) String ¶
func (m ModulePath) String() string
String representation of the path component of an address.
type Option ¶
type Option func(*parser) Option
Option is a function that can set an option on the parser. It returns the previous setting as an Option.
func AllowInvalidUTF8 ¶
AllowInvalidUTF8 creates an Option to allow invalid UTF-8 bytes. Every invalid UTF-8 byte is treated as a utf8.RuneError (U+FFFD) by character class matchers and is matched by the any matcher. The returned matched value, c.text and c.offset are NOT affected.
The default is false.
func Debug ¶
Debug creates an Option to set the debug flag to b. When set to true, debugging information is printed to stdout while parsing.
The default is false.
func Entrypoint ¶
Entrypoint creates an Option to set the rule name to use as entrypoint. The rule name must have been specified in the -alternate-entrypoints if generating the parser with the -optimize-grammar flag, otherwise it may have been optimized out. Passing an empty string sets the entrypoint to the first rule in the grammar.
The default is to start parsing at the first rule in the grammar.
func GlobalStore ¶
GlobalStore creates an Option to set a key to a certain value in the globalStore.
func InitState ¶
InitState creates an Option to set a key to a certain value in the global "state" store.
func MaxExpressions ¶
MaxExpressions creates an Option to stop parsing after the provided number of expressions have been parsed, if the value is 0 then the parser will parse for as many steps as needed (possibly an infinite number).
The default for maxExprCnt is 0.
func Memoize ¶
Memoize creates an Option to set the memoize flag to b. When set to true, the parser will cache all results so each expression is evaluated only once. This guarantees linear parsing time even for pathological cases, at the expense of more memory and slower times for typical cases.
The default is false.
func Recover ¶
Recover creates an Option to set the recover flag to b. When set to true, this causes the parser to recover from panics and convert it to an error. Setting it to false can be useful while debugging to access the full stack trace.
The default is true.
func Statistics ¶
Statistics adds a user provided Stats struct to the parser to allow the user to process the results after the parsing has finished. Also the key for the "no match" counter is set.
Example usage:
input := "input"
stats := Stats{}
_, err := Parse("input-file", []byte(input), Statistics(&stats, "no match"))
if err != nil {
log.Panicln(err)
}
b, err := json.MarshalIndent(stats.ChoiceAltCnt, "", " ")
if err != nil {
log.Panicln(err)
}
fmt.Println(string(b))
type ResourceSpec ¶
ResourceSpec describes the resource of an address. resource_type.resource_name[resource index]
func (*ResourceSpec) String ¶
func (r *ResourceSpec) String() string
String representation of the resource component of an address.
type Stats ¶
type Stats struct {
// ExprCnt counts the number of expressions processed during parsing
// This value is compared to the maximum number of expressions allowed
// (set by the MaxExpressions option).
ExprCnt uint64
// ChoiceAltCnt is used to count for each ordered choice expression,
// which alternative is used how may times.
// These numbers allow to optimize the order of the ordered choice expression
// to increase the performance of the parser
//
// The outer key of ChoiceAltCnt is composed of the name of the rule as well
// as the line and the column of the ordered choice.
// The inner key of ChoiceAltCnt is the number (one-based) of the matching alternative.
// For each alternative the number of matches are counted. If an ordered choice does not
// match, a special counter is incremented. The name of this counter is set with
// the parser option Statistics.
// For an alternative to be included in ChoiceAltCnt, it has to match at least once.
ChoiceAltCnt map[string]map[string]int
}
Stats stores some statistics, gathered during parsing
Source Files