terraform/config/module/tree.go

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package module
import (
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"bufio"
"bytes"
"fmt"
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"path/filepath"
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"strings"
"sync"
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"github.com/hashicorp/go-getter"
"github.com/hashicorp/terraform/config"
)
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// RootName is the name of the root tree.
const RootName = "root"
// Tree represents the module import tree of configurations.
//
// This Tree structure can be used to get (download) new modules, load
// all the modules without getting, flatten the tree into something
// Terraform can use, etc.
type Tree struct {
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name string
config *config.Config
children map[string]*Tree
path []string
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lock sync.RWMutex
}
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// NewTree returns a new Tree for the given config structure.
func NewTree(name string, c *config.Config) *Tree {
return &Tree{config: c, name: name}
}
// NewEmptyTree returns a new tree that is empty (contains no configuration).
func NewEmptyTree() *Tree {
t := &Tree{config: &config.Config{}}
// We do this dummy load so that the tree is marked as "loaded". It
// should never fail because this is just about a no-op. If it does fail
// we panic so we can know its a bug.
if err := t.Load(nil, GetModeGet); err != nil {
panic(err)
}
return t
}
// NewTreeModule is like NewTree except it parses the configuration in
// the directory and gives it a specific name. Use a blank name "" to specify
// the root module.
func NewTreeModule(name, dir string) (*Tree, error) {
c, err := config.LoadDir(dir)
if err != nil {
return nil, err
}
return NewTree(name, c), nil
}
// Config returns the configuration for this module.
func (t *Tree) Config() *config.Config {
return t.config
}
// Child returns the child with the given path (by name).
func (t *Tree) Child(path []string) *Tree {
if len(path) == 0 {
return t
}
c := t.Children()[path[0]]
if c == nil {
return nil
}
return c.Child(path[1:])
}
// Children returns the children of this tree (the modules that are
// imported by this root).
//
// This will only return a non-nil value after Load is called.
func (t *Tree) Children() map[string]*Tree {
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t.lock.RLock()
defer t.lock.RUnlock()
return t.children
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}
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// Loaded says whether or not this tree has been loaded or not yet.
func (t *Tree) Loaded() bool {
t.lock.RLock()
defer t.lock.RUnlock()
return t.children != nil
}
// Modules returns the list of modules that this tree imports.
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//
// This is only the imports of _this_ level of the tree. To retrieve the
// full nested imports, you'll have to traverse the tree.
func (t *Tree) Modules() []*Module {
result := make([]*Module, len(t.config.Modules))
for i, m := range t.config.Modules {
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result[i] = &Module{
Name: m.Name,
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Source: m.Source,
}
}
return result
}
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// Name returns the name of the tree. This will be "<root>" for the root
// tree and then the module name given for any children.
func (t *Tree) Name() string {
if t.name == "" {
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return RootName
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}
return t.name
}
// Load loads the configuration of the entire tree.
//
// The parameters are used to tell the tree where to find modules and
// whether it can download/update modules along the way.
//
// Calling this multiple times will reload the tree.
//
// Various semantic-like checks are made along the way of loading since
// module trees inherently require the configuration to be in a reasonably
// sane state: no circular dependencies, proper module sources, etc. A full
// suite of validations can be done by running Validate (after loading).
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func (t *Tree) Load(s getter.Storage, mode GetMode) error {
t.lock.Lock()
defer t.lock.Unlock()
// Reset the children if we have any
t.children = nil
modules := t.Modules()
children := make(map[string]*Tree)
// Go through all the modules and get the directory for them.
for _, m := range modules {
if _, ok := children[m.Name]; ok {
return fmt.Errorf(
"module %s: duplicated. module names must be unique", m.Name)
}
// Determine the path to this child
path := make([]string, len(t.path), len(t.path)+1)
copy(path, t.path)
path = append(path, m.Name)
// Split out the subdir if we have one
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source, subDir := getter.SourceDirSubdir(m.Source)
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source, err := getter.Detect(source, t.config.Dir, getter.Detectors)
if err != nil {
return fmt.Errorf("module %s: %s", m.Name, err)
}
// Check if the detector introduced something new.
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source, subDir2 := getter.SourceDirSubdir(source)
if subDir2 != "" {
subDir = filepath.Join(subDir2, subDir)
}
// Get the directory where this module is so we can load it
key := strings.Join(path, ".")
key = fmt.Sprintf("root.%s-%s", key, m.Source)
dir, ok, err := getStorage(s, key, source, mode)
if err != nil {
return err
}
if !ok {
return fmt.Errorf(
"module %s: not found, may need to be downloaded using 'terraform get'", m.Name)
}
// If we have a subdirectory, then merge that in
if subDir != "" {
dir = filepath.Join(dir, subDir)
}
// Load the configurations.Dir(source)
children[m.Name], err = NewTreeModule(m.Name, dir)
if err != nil {
return fmt.Errorf(
"module %s: %s", m.Name, err)
}
// Set the path of this child
children[m.Name].path = path
}
// Go through all the children and load them.
for _, c := range children {
if err := c.Load(s, mode); err != nil {
return err
}
}
// Set our tree up
t.children = children
return nil
}
// Path is the full path to this tree.
func (t *Tree) Path() []string {
return t.path
}
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// String gives a nice output to describe the tree.
func (t *Tree) String() string {
var result bytes.Buffer
path := strings.Join(t.path, ", ")
if path != "" {
path = fmt.Sprintf(" (path: %s)", path)
}
result.WriteString(t.Name() + path + "\n")
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cs := t.Children()
if cs == nil {
result.WriteString(" not loaded")
} else {
// Go through each child and get its string value, then indent it
// by two.
for _, c := range cs {
r := strings.NewReader(c.String())
scanner := bufio.NewScanner(r)
for scanner.Scan() {
result.WriteString(" ")
result.WriteString(scanner.Text())
result.WriteString("\n")
}
}
}
return result.String()
}
// Validate does semantic checks on the entire tree of configurations.
//
// This will call the respective config.Config.Validate() functions as well
// as verifying things such as parameters/outputs between the various modules.
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//
// Load must be called prior to calling Validate or an error will be returned.
func (t *Tree) Validate() error {
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if !t.Loaded() {
return fmt.Errorf("tree must be loaded before calling Validate")
}
// If something goes wrong, here is our error template
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newErr := &TreeError{Name: []string{t.Name()}}
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// Validate our configuration first.
if err := t.config.Validate(); err != nil {
newErr.Err = err
return newErr
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}
// Get the child trees
children := t.Children()
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// Validate all our children
for _, c := range children {
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err := c.Validate()
if err == nil {
continue
}
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verr, ok := err.(*TreeError)
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if !ok {
// Unknown error, just return...
return err
}
// Append ourselves to the error and then return
verr.Name = append(verr.Name, t.Name())
return verr
}
// Go over all the modules and verify that any parameters are valid
// variables into the module in question.
for _, m := range t.config.Modules {
tree, ok := children[m.Name]
if !ok {
// This should never happen because Load watches us
panic("module not found in children: " + m.Name)
}
// Build the variables that the module defines
requiredMap := make(map[string]struct{})
varMap := make(map[string]struct{})
for _, v := range tree.config.Variables {
varMap[v.Name] = struct{}{}
if v.Required() {
requiredMap[v.Name] = struct{}{}
}
}
// Compare to the keys in our raw config for the module
for k, _ := range m.RawConfig.Raw {
if _, ok := varMap[k]; !ok {
newErr.Err = fmt.Errorf(
"module %s: %s is not a valid parameter",
m.Name, k)
return newErr
}
// Remove the required
delete(requiredMap, k)
}
// If we have any required left over, they aren't set.
for k, _ := range requiredMap {
newErr.Err = fmt.Errorf(
"module %s: required variable %s not set",
m.Name, k)
return newErr
}
}
// Go over all the variables used and make sure that any module
// variables represent outputs properly.
for source, vs := range t.config.InterpolatedVariables() {
for _, v := range vs {
mv, ok := v.(*config.ModuleVariable)
if !ok {
continue
}
tree, ok := children[mv.Name]
if !ok {
// This should never happen because Load watches us
panic("module not found in children: " + mv.Name)
}
found := false
for _, o := range tree.config.Outputs {
if o.Name == mv.Field {
found = true
break
}
}
if !found {
newErr.Err = fmt.Errorf(
"%s: %s is not a valid output for module %s",
source, mv.Field, mv.Name)
return newErr
}
}
}
return nil
}
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// TreeError is an error returned by Tree.Validate if an error occurs
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// with validation.
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type TreeError struct {
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Name []string
Err error
}
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func (e *TreeError) Error() string {
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// Build up the name
var buf bytes.Buffer
for _, n := range e.Name {
buf.WriteString(n)
buf.WriteString(".")
}
buf.Truncate(buf.Len() - 1)
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// Format the value
return fmt.Sprintf("module %s: %s", buf.String(), e.Err)
}