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Copy pathcontext.go
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850 lines (730 loc) · 23.9 KB
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package terraform
import (
"fmt"
"log"
"sort"
"strings"
"sync"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/hcl"
"github.com/hashicorp/terraform/config"
"github.com/hashicorp/terraform/config/module"
)
// Variables prefixed with X_ are experimental features. They can be enabled
// by setting them to true. This should be done before any API is called.
// These should be expected to be removed at some point in the future; each
// option should mention a schedule.
var (
// X_newApply will enable the new apply graph. This will be removed
// and be on by default in 0.8.0.
X_newApply = false
)
// InputMode defines what sort of input will be asked for when Input
// is called on Context.
type InputMode byte
const (
// InputModeVar asks for all variables
InputModeVar InputMode = 1 << iota
// InputModeVarUnset asks for variables which are not set yet
InputModeVarUnset
// InputModeProvider asks for provider variables
InputModeProvider
// InputModeStd is the standard operating mode and asks for both variables
// and providers.
InputModeStd = InputModeVar | InputModeProvider
)
var (
// contextFailOnShadowError will cause Context operations to return
// errors when shadow operations fail. This is only used for testing.
contextFailOnShadowError = false
// contextTestDeepCopyOnPlan will perform a Diff DeepCopy on every
// Plan operation, effectively testing the Diff DeepCopy whenever
// a Plan occurs. This is enabled for tests.
contextTestDeepCopyOnPlan = false
// contextTestShadow will enable the shadow graph for the new graphs.
// This is enabled for tests. This will be removed very shortly and
// be enabled by default.
contextTestShadow = false
)
// ContextOpts are the user-configurable options to create a context with
// NewContext.
type ContextOpts struct {
Destroy bool
Diff *Diff
Hooks []Hook
Module *module.Tree
Parallelism int
State *State
StateFutureAllowed bool
Providers map[string]ResourceProviderFactory
Provisioners map[string]ResourceProvisionerFactory
Shadow bool
Targets []string
Variables map[string]interface{}
UIInput UIInput
}
// Context represents all the context that Terraform needs in order to
// perform operations on infrastructure. This structure is built using
// NewContext. See the documentation for that.
//
// Extra functions on Context can be found in context_*.go files.
type Context struct {
// Maintainer note: Anytime this struct is changed, please verify
// that newShadowContext still does the right thing. Tests should
// fail regardless but putting this note here as well.
components contextComponentFactory
destroy bool
diff *Diff
diffLock sync.RWMutex
hooks []Hook
module *module.Tree
sh *stopHook
shadow bool
state *State
stateLock sync.RWMutex
targets []string
uiInput UIInput
variables map[string]interface{}
l sync.Mutex // Lock acquired during any task
parallelSem Semaphore
providerInputConfig map[string]map[string]interface{}
runCh <-chan struct{}
shadowErr error
}
// NewContext creates a new Context structure.
//
// Once a Context is creator, the pointer values within ContextOpts
// should not be mutated in any way, since the pointers are copied, not
// the values themselves.
func NewContext(opts *ContextOpts) (*Context, error) {
// Copy all the hooks and add our stop hook. We don't append directly
// to the Config so that we're not modifying that in-place.
sh := new(stopHook)
hooks := make([]Hook, len(opts.Hooks)+1)
copy(hooks, opts.Hooks)
hooks[len(opts.Hooks)] = sh
state := opts.State
if state == nil {
state = new(State)
state.init()
}
// If our state is from the future, then error. Callers can avoid
// this error by explicitly setting `StateFutureAllowed`.
if !opts.StateFutureAllowed && state.FromFutureTerraform() {
return nil, fmt.Errorf(
"Terraform doesn't allow running any operations against a state\n"+
"that was written by a future Terraform version. The state is\n"+
"reporting it is written by Terraform '%s'.\n\n"+
"Please run at least that version of Terraform to continue.",
state.TFVersion)
}
// Explicitly reset our state version to our current version so that
// any operations we do will write out that our latest version
// has run.
state.TFVersion = Version
// Determine parallelism, default to 10. We do this both to limit
// CPU pressure but also to have an extra guard against rate throttling
// from providers.
par := opts.Parallelism
if par == 0 {
par = 10
}
// Set up the variables in the following sequence:
// 0 - Take default values from the configuration
// 1 - Take values from TF_VAR_x environment variables
// 2 - Take values specified in -var flags, overriding values
// set by environment variables if necessary. This includes
// values taken from -var-file in addition.
variables := make(map[string]interface{})
if opts.Module != nil {
var err error
variables, err = Variables(opts.Module, opts.Variables)
if err != nil {
return nil, err
}
}
return &Context{
components: &basicComponentFactory{
providers: opts.Providers,
provisioners: opts.Provisioners,
},
destroy: opts.Destroy,
diff: opts.Diff,
hooks: hooks,
module: opts.Module,
shadow: opts.Shadow,
state: state,
targets: opts.Targets,
uiInput: opts.UIInput,
variables: variables,
parallelSem: NewSemaphore(par),
providerInputConfig: make(map[string]map[string]interface{}),
sh: sh,
}, nil
}
type ContextGraphOpts struct {
Validate bool
Verbose bool
}
// Graph returns the graph for this config.
func (c *Context) Graph(g *ContextGraphOpts) (*Graph, error) {
return c.graphBuilder(g).Build(RootModulePath)
}
// GraphBuilder returns the GraphBuilder that will be used to create
// the graphs for this context.
func (c *Context) graphBuilder(g *ContextGraphOpts) GraphBuilder {
return &BuiltinGraphBuilder{
Root: c.module,
Diff: c.diff,
Providers: c.components.ResourceProviders(),
Provisioners: c.components.ResourceProvisioners(),
State: c.state,
Targets: c.targets,
Destroy: c.destroy,
Validate: g.Validate,
Verbose: g.Verbose,
}
}
// ShadowError returns any errors caught during a shadow operation.
//
// A shadow operation is an operation run in parallel to a real operation
// that performs the same tasks using new logic on copied state. The results
// are compared to ensure that the new logic works the same as the old logic.
// The shadow never affects the real operation or return values.
//
// The result of the shadow operation are only available through this function
// call after a real operation is complete.
//
// For API consumers of Context, you can safely ignore this function
// completely if you have no interest in helping report experimental feature
// errors to Terraform maintainers. Otherwise, please call this function
// after every operation and report this to the user.
//
// IMPORTANT: Shadow errors are _never_ critical: they _never_ affect
// the real state or result of a real operation. They are purely informational
// to assist in future Terraform versions being more stable. Please message
// this effectively to the end user.
//
// This must be called only when no other operation is running (refresh,
// plan, etc.). The result can be used in parallel to any other operation
// running.
func (c *Context) ShadowError() error {
return c.shadowErr
}
// Input asks for input to fill variables and provider configurations.
// This modifies the configuration in-place, so asking for Input twice
// may result in different UI output showing different current values.
func (c *Context) Input(mode InputMode) error {
v := c.acquireRun()
defer c.releaseRun(v)
if mode&InputModeVar != 0 {
// Walk the variables first for the root module. We walk them in
// alphabetical order for UX reasons.
rootConf := c.module.Config()
names := make([]string, len(rootConf.Variables))
m := make(map[string]*config.Variable)
for i, v := range rootConf.Variables {
names[i] = v.Name
m[v.Name] = v
}
sort.Strings(names)
for _, n := range names {
// If we only care about unset variables, then if the variable
// is set, continue on.
if mode&InputModeVarUnset != 0 {
if _, ok := c.variables[n]; ok {
continue
}
}
var valueType config.VariableType
v := m[n]
switch valueType = v.Type(); valueType {
case config.VariableTypeUnknown:
continue
case config.VariableTypeMap:
// OK
case config.VariableTypeList:
// OK
case config.VariableTypeString:
// OK
default:
panic(fmt.Sprintf("Unknown variable type: %#v", v.Type()))
}
// If the variable is not already set, and the variable defines a
// default, use that for the value.
if _, ok := c.variables[n]; !ok {
if v.Default != nil {
c.variables[n] = v.Default.(string)
continue
}
}
// this should only happen during tests
if c.uiInput == nil {
log.Println("[WARN] Content.uiInput is nil")
continue
}
// Ask the user for a value for this variable
var value string
retry := 0
for {
var err error
value, err = c.uiInput.Input(&InputOpts{
Id: fmt.Sprintf("var.%s", n),
Query: fmt.Sprintf("var.%s", n),
Description: v.Description,
})
if err != nil {
return fmt.Errorf(
"Error asking for %s: %s", n, err)
}
if value == "" && v.Required() {
// Redo if it is required, but abort if we keep getting
// blank entries
if retry > 2 {
return fmt.Errorf("missing required value for %q", n)
}
retry++
continue
}
break
}
// no value provided, so don't set the variable at all
if value == "" {
continue
}
decoded, err := parseVariableAsHCL(n, value, valueType)
if err != nil {
return err
}
if decoded != nil {
c.variables[n] = decoded
}
}
}
if mode&InputModeProvider != 0 {
// Build the graph
graph, err := c.Graph(&ContextGraphOpts{Validate: true})
if err != nil {
return err
}
// Do the walk
if _, err := c.walk(graph, nil, walkInput); err != nil {
return err
}
}
return nil
}
// Apply applies the changes represented by this context and returns
// the resulting state.
//
// In addition to returning the resulting state, this context is updated
// with the latest state.
func (c *Context) Apply() (*State, error) {
v := c.acquireRun()
defer c.releaseRun(v)
// Copy our own state
c.state = c.state.DeepCopy()
// Build the original graph. This is before the new graph builders
// coming in 0.8. We do this for shadow graphing.
oldGraph, err := c.Graph(&ContextGraphOpts{Validate: true})
if err != nil && X_newApply {
// If we had an error graphing but we're using the new graph,
// just set it to nil and let it go. There are some features that
// may work with the new graph that don't with the old.
oldGraph = nil
err = nil
}
if err != nil {
return nil, err
}
// Build the new graph. We do this no matter what so we can shadow it.
newGraph, err := (&ApplyGraphBuilder{
Module: c.module,
Diff: c.diff,
State: c.state,
Providers: c.components.ResourceProviders(),
Provisioners: c.components.ResourceProvisioners(),
}).Build(RootModulePath)
if err != nil && !X_newApply {
// If we had an error graphing but we're not using this graph, just
// set it to nil and record it as a shadow error.
c.shadowErr = multierror.Append(c.shadowErr, fmt.Errorf(
"Error building new apply graph: %s", err))
newGraph = nil
err = nil
}
if err != nil {
return nil, err
}
// Determine what is the real and what is the shadow. The logic here
// is straightforward though the if statements are not:
//
// * Destroy mode - always use original, shadow with nothing because
// we're only testing the new APPLY graph.
// * Apply with new apply - use new graph, shadow is new graph. We can't
// shadow with the old graph because the old graph does a lot more
// that it shouldn't.
// * Apply with old apply - use old graph, shadow with new graph.
//
real := oldGraph
shadow := newGraph
if c.destroy {
log.Printf("[WARN] terraform: real graph is original, shadow is nil")
shadow = nil
} else {
if X_newApply {
log.Printf("[WARN] terraform: real graph is Xnew-apply, shadow is Xnew-apply")
real = shadow
} else {
log.Printf("[WARN] terraform: real graph is original, shadow is Xnew-apply")
}
}
// For now, always shadow with the real graph for verification. We don't
// want to shadow yet with the new graphs.
if !contextTestShadow {
shadow = real
}
// Determine the operation
operation := walkApply
if c.destroy {
operation = walkDestroy
}
// This shouldn't happen, so assert it. This is before any state changes
// so it is safe to crash here.
if real == nil {
panic("nil real graph")
}
// Walk the graph
walker, err := c.walk(real, shadow, operation)
if len(walker.ValidationErrors) > 0 {
err = multierror.Append(err, walker.ValidationErrors...)
}
// Clean out any unused things
c.state.prune()
return c.state, err
}
// Plan generates an execution plan for the given context.
//
// The execution plan encapsulates the context and can be stored
// in order to reinstantiate a context later for Apply.
//
// Plan also updates the diff of this context to be the diff generated
// by the plan, so Apply can be called after.
func (c *Context) Plan() (*Plan, error) {
v := c.acquireRun()
defer c.releaseRun(v)
p := &Plan{
Module: c.module,
Vars: c.variables,
State: c.state,
Targets: c.targets,
}
var operation walkOperation
if c.destroy {
operation = walkPlanDestroy
} else {
// Set our state to be something temporary. We do this so that
// the plan can update a fake state so that variables work, then
// we replace it back with our old state.
old := c.state
if old == nil {
c.state = &State{}
c.state.init()
} else {
c.state = old.DeepCopy()
}
defer func() {
c.state = old
}()
operation = walkPlan
}
// Setup our diff
c.diffLock.Lock()
c.diff = new(Diff)
c.diff.init()
c.diffLock.Unlock()
// Build the graph
graph, err := c.Graph(&ContextGraphOpts{Validate: true})
if err != nil {
return nil, err
}
// Do the walk
walker, err := c.walk(graph, graph, operation)
if err != nil {
return nil, err
}
p.Diff = c.diff
// If this is true, it means we're running unit tests. In this case,
// we perform a deep copy just to ensure that all context tests also
// test that a diff is copy-able. This will panic if it fails. This
// is enabled during unit tests.
//
// This should never be true during production usage, but even if it is,
// it can't do any real harm.
if contextTestDeepCopyOnPlan {
p.Diff.DeepCopy()
}
// Now that we have a diff, we can build the exact graph that Apply will use
// and catch any possible cycles during the Plan phase.
if _, err := c.Graph(&ContextGraphOpts{Validate: true}); err != nil {
return nil, err
}
var errs error
if len(walker.ValidationErrors) > 0 {
errs = multierror.Append(errs, walker.ValidationErrors...)
}
return p, errs
}
// Refresh goes through all the resources in the state and refreshes them
// to their latest state. This will update the state that this context
// works with, along with returning it.
//
// Even in the case an error is returned, the state will be returned and
// will potentially be partially updated.
func (c *Context) Refresh() (*State, error) {
v := c.acquireRun()
defer c.releaseRun(v)
// Copy our own state
c.state = c.state.DeepCopy()
// Build the graph
graph, err := c.Graph(&ContextGraphOpts{Validate: true})
if err != nil {
return nil, err
}
// Do the walk
if _, err := c.walk(graph, graph, walkRefresh); err != nil {
return nil, err
}
// Clean out any unused things
c.state.prune()
return c.state, nil
}
// Stop stops the running task.
//
// Stop will block until the task completes.
func (c *Context) Stop() {
c.l.Lock()
ch := c.runCh
// If we aren't running, then just return
if ch == nil {
c.l.Unlock()
return
}
// Tell the hook we want to stop
c.sh.Stop()
// Wait for us to stop
c.l.Unlock()
<-ch
}
// Validate validates the configuration and returns any warnings or errors.
func (c *Context) Validate() ([]string, []error) {
v := c.acquireRun()
defer c.releaseRun(v)
var errs error
// Validate the configuration itself
if err := c.module.Validate(); err != nil {
errs = multierror.Append(errs, err)
}
// This only needs to be done for the root module, since inter-module
// variables are validated in the module tree.
if config := c.module.Config(); config != nil {
// Validate the user variables
if err := smcUserVariables(config, c.variables); len(err) > 0 {
errs = multierror.Append(errs, err...)
}
}
// If we have errors at this point, the graphing has no chance,
// so just bail early.
if errs != nil {
return nil, []error{errs}
}
// Build the graph so we can walk it and run Validate on nodes.
// We also validate the graph generated here, but this graph doesn't
// necessarily match the graph that Plan will generate, so we'll validate the
// graph again later after Planning.
graph, err := c.Graph(&ContextGraphOpts{Validate: true})
if err != nil {
return nil, []error{err}
}
// Walk
walker, err := c.walk(graph, graph, walkValidate)
if err != nil {
return nil, multierror.Append(errs, err).Errors
}
// Return the result
rerrs := multierror.Append(errs, walker.ValidationErrors...)
return walker.ValidationWarnings, rerrs.Errors
}
// Module returns the module tree associated with this context.
func (c *Context) Module() *module.Tree {
return c.module
}
// Variables will return the mapping of variables that were defined
// for this Context. If Input was called, this mapping may be different
// than what was given.
func (c *Context) Variables() map[string]interface{} {
return c.variables
}
// SetVariable sets a variable after a context has already been built.
func (c *Context) SetVariable(k string, v interface{}) {
c.variables[k] = v
}
func (c *Context) acquireRun() chan<- struct{} {
c.l.Lock()
defer c.l.Unlock()
// Wait for no channel to exist
for c.runCh != nil {
c.l.Unlock()
ch := c.runCh
<-ch
c.l.Lock()
}
// Create the new channel
ch := make(chan struct{})
c.runCh = ch
// Reset the stop hook so we're not stopped
c.sh.Reset()
// Reset the shadow errors
c.shadowErr = nil
return ch
}
func (c *Context) releaseRun(ch chan<- struct{}) {
c.l.Lock()
defer c.l.Unlock()
close(ch)
c.runCh = nil
}
func (c *Context) walk(
graph, shadow *Graph, operation walkOperation) (*ContextGraphWalker, error) {
// Keep track of the "real" context which is the context that does
// the real work: talking to real providers, modifying real state, etc.
realCtx := c
// If we have a shadow graph, walk that as well
var shadowCtx *Context
var shadowCloser Shadow
if c.shadow && shadow != nil {
// Build the shadow context. In the process, override the real context
// with the one that is wrapped so that the shadow context can verify
// the results of the real.
realCtx, shadowCtx, shadowCloser = newShadowContext(c)
}
// Just log this so we can see it in a debug log
if !c.shadow {
log.Printf("[WARN] terraform: shadow graph disabled")
}
// Build the real graph walker
log.Printf("[DEBUG] Starting graph walk: %s", operation.String())
walker := &ContextGraphWalker{Context: realCtx, Operation: operation}
// Walk the real graph, this will block until it completes
realErr := graph.Walk(walker)
// If we have a shadow graph and we interrupted the real graph, then
// we just close the shadow and never verify it. It is non-trivial to
// recreate the exact execution state up until an interruption so this
// isn't supported with shadows at the moment.
if shadowCloser != nil && c.sh.Stopped() {
// Ignore the error result, there is nothing we could care about
shadowCloser.CloseShadow()
// Set it to nil so we don't do anything
shadowCloser = nil
}
// If we have a shadow graph, wait for that to complete.
if shadowCloser != nil {
// Build the graph walker for the shadow.
shadowWalker := &ContextGraphWalker{
Context: shadowCtx,
Operation: operation,
}
// Kick off the shadow walk. This will block on any operations
// on the real walk so it is fine to start first.
log.Printf("[INFO] Starting shadow graph walk: %s", operation.String())
shadowCh := make(chan error)
go func() {
shadowCh <- shadow.Walk(shadowWalker)
}()
// Notify the shadow that we're done
if err := shadowCloser.CloseShadow(); err != nil {
c.shadowErr = multierror.Append(c.shadowErr, err)
}
// Wait for the walk to end
log.Printf("[DEBUG] Waiting for shadow graph to complete...")
shadowWalkErr := <-shadowCh
// Get any shadow errors
if err := shadowCloser.ShadowError(); err != nil {
c.shadowErr = multierror.Append(c.shadowErr, err)
}
// Verify the contexts (compare)
if err := shadowContextVerify(realCtx, shadowCtx); err != nil {
c.shadowErr = multierror.Append(c.shadowErr, err)
}
// At this point, if we're supposed to fail on error, then
// we PANIC. Some tests just verify that there is an error,
// so simply appending it to realErr and returning could hide
// shadow problems.
//
// This must be done BEFORE appending shadowWalkErr since the
// shadowWalkErr may include expected errors.
if c.shadowErr != nil && contextFailOnShadowError {
panic(multierror.Prefix(c.shadowErr, "shadow graph:"))
}
// Now, if we have a walk error, we append that through
if shadowWalkErr != nil {
c.shadowErr = multierror.Append(c.shadowErr, shadowWalkErr)
}
if c.shadowErr == nil {
log.Printf("[INFO] Shadow graph success!")
} else {
log.Printf("[ERROR] Shadow graph error: %s", c.shadowErr)
// If we're supposed to fail on shadow errors, then report it
if contextFailOnShadowError {
realErr = multierror.Append(realErr, multierror.Prefix(
c.shadowErr, "shadow graph:"))
}
}
}
return walker, realErr
}
// parseVariableAsHCL parses the value of a single variable as would have been specified
// on the command line via -var or in an environment variable named TF_VAR_x, where x is
// the name of the variable. In order to get around the restriction of HCL requiring a
// top level object, we prepend a sentinel key, decode the user-specified value as its
// value and pull the value back out of the resulting map.
func parseVariableAsHCL(name string, input string, targetType config.VariableType) (interface{}, error) {
// expecting a string so don't decode anything, just strip quotes
if targetType == config.VariableTypeString {
return strings.Trim(input, `"`), nil
}
// return empty types
if strings.TrimSpace(input) == "" {
switch targetType {
case config.VariableTypeList:
return []interface{}{}, nil
case config.VariableTypeMap:
return make(map[string]interface{}), nil
}
}
const sentinelValue = "SENTINEL_TERRAFORM_VAR_OVERRIDE_KEY"
inputWithSentinal := fmt.Sprintf("%s = %s", sentinelValue, input)
var decoded map[string]interface{}
err := hcl.Decode(&decoded, inputWithSentinal)
if err != nil {
return nil, fmt.Errorf("Cannot parse value for variable %s (%q) as valid HCL: %s", name, input, err)
}
if len(decoded) != 1 {
return nil, fmt.Errorf("Cannot parse value for variable %s (%q) as valid HCL. Only one value may be specified.", name, input)
}
parsedValue, ok := decoded[sentinelValue]
if !ok {
return nil, fmt.Errorf("Cannot parse value for variable %s (%q) as valid HCL. One value must be specified.", name, input)
}
switch targetType {
case config.VariableTypeList:
return parsedValue, nil
case config.VariableTypeMap:
if list, ok := parsedValue.([]map[string]interface{}); ok {
return list[0], nil
}
return nil, fmt.Errorf("Cannot parse value for variable %s (%q) as valid HCL. One value must be specified.", name, input)
default:
panic(fmt.Errorf("unknown type %s", targetType.Printable()))
}
}