vm

Documentation

Overview

Package vm exposes the capabilities of a Jsonnet VM as a narrow interface. The returned implementation is automatically set up with the native functions and importers that qbec supports and is safe for concurrent use.

Example

package main

import (
	"fmt"

	"github.com/splunk/qbec/vm"
)

func main() {
	jvm := vm.New(vm.Config{})

	code := `
function (str, num) {
	foo: str,
	bar: num,
	baz: std.extVar('baz'),
}
`
	vs := vm.VariableSet{}.
		WithTopLevelVars(
			vm.NewVar("str", "hello"),
			vm.NewCodeVar("num", "10"),
		).
		WithVars(
			vm.NewVar("baz", "world"),
		)

	out, err := jvm.EvalCode("inline-code.jsonnet", vm.MakeCode(code), vs)
	if err != nil {
		panic(err)
	}

	fmt.Println(out)
}

Output:

{
   "bar": 10,
   "baz": "world",
   "foo": "hello"
}

Index

• func ConfigProviderFromVariables(vs VariableSet) datasource.ConfigProvider
• func CreateDataSources(input []string, cp datasource.ConfigProvider) (sources []datasource.DataSource, closer io.Closer, _ error)
• func MakeSnippet(filename, s string) linter.Snippet
• type Code
  • func MakeCode(s string) Code
• type Config
• type VM
  • func New(config Config) VM
• type Var
  • func NewCodeVar(name, code string) Var
  • func NewVar(name, value string) Var
• type VariableSet
  • func (vs VariableSet) HasTopLevelVar(name string) bool
  • func (vs VariableSet) HasVar(name string) bool
  • func (vs VariableSet) TopLevelVars() []Var
  • func (vs VariableSet) Vars() []Var
  • func (vs VariableSet) WithTopLevelVars(add ...Var) VariableSet
  • func (vs VariableSet) WithVars(add ...Var) VariableSet
  • func (vs VariableSet) WithoutTopLevel() VariableSet

Examples

• Package

Functions

func ConfigProviderFromVariables

func ConfigProviderFromVariables(vs VariableSet) datasource.ConfigProvider

ConfigProviderFromVariables returns a simple config provider for data sources based on a static set of variables that will be defined for the VM.

func CreateDataSources

func CreateDataSources(input []string, cp datasource.ConfigProvider) (sources []datasource.DataSource, closer io.Closer, _ error)

CreateDataSources returns the data source implementations for the supplied URIs. It also returns an io.Closer that should be called at the point when the data sources are no longer in use. It guarantees that the returned closer will be non-nil even when there are errors.

func MakeSnippet

func MakeSnippet(filename, s string) linter.Snippet

MakeSnippet returns a linter Snippet from the supplied filename and the code string

Types

type Code

type Code struct {
	// contains filtered or unexported fields
}

Code wraps string to distinguish it from string file names

func MakeCode

func MakeCode(s string) Code

MakeCode returns a code object from the supplied string.

type Config

type Config struct {
	LibPaths    []string                // library paths
	DataSources []datasource.DataSource // data sources
}

Config is the configuration of the VM

type VM

type VM interface {
	// EvalFile evaluates the supplied file initializing the VM with the supplied variables
	// and returns its output as a JSON string.
	EvalFile(file string, v VariableSet) (string, error)
	// EvalCode evaluates the supplied code initializing the VM with the supplied variables
	// and returns its output as a JSON string.
	EvalCode(diagnosticFile string, code Code, v VariableSet) (string, error)
	// LintCode uses the jsonnet linter to lint the code and returns any errors
	LintCode(linter.Snippet) error
}

VM provides a narrow interface to the capabilities of a jsonnet VM.

func New

func New(config Config) VM

New constructs a new VM based on the supplied config. The returned VM interface is safe for concurrent use.

type Var

type Var struct {
	Name string
	// contains filtered or unexported fields
}

Var is an opaque variable to be initialized for the jsonnet VM

func NewCodeVar

func NewCodeVar(name, code string) Var

NewCodeVar returns a variable that has a code value

func NewVar

func NewVar(name, value string) Var

NewVar returns a variable that has a string value

type VariableSet

type VariableSet struct {
	// contains filtered or unexported fields
}

VariableSet is an immutable set of variables to be registered with a jsonnet VM

func (VariableSet) HasTopLevelVar

func (vs VariableSet) HasTopLevelVar(name string) bool

HasTopLevelVar returns true if the specified TLA variable is defined.

func (VariableSet) HasVar

func (vs VariableSet) HasVar(name string) bool

HasVar returns true if the specified external variable is defined.

func (VariableSet) TopLevelVars

func (vs VariableSet) TopLevelVars() []Var

TopLevelVars returns the string top-level variables defined for this variable set.

func (VariableSet) Vars

func (vs VariableSet) Vars() []Var

Vars returns the names of all variables defined for this variable set.

func (VariableSet) WithTopLevelVars

func (vs VariableSet) WithTopLevelVars(add ...Var) VariableSet

WithTopLevelVars returns a variable set with additional top-level string variables in its environment.

func (VariableSet) WithVars

func (vs VariableSet) WithVars(add ...Var) VariableSet

WithVars returns a variable set with additional variables in its environment.

func (VariableSet) WithoutTopLevel

func (vs VariableSet) WithoutTopLevel() VariableSet

WithoutTopLevel returns a variable set that does not have any top level variables set.