1 files changed, 158 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/terraform/terraform/shadow_context.go b/vendor/github.com/hashicorp/terraform/terraform/shadow_context.go
new file mode 100644
index 00000000..5588af25
--- /dev/null
+++ b/vendor/github.com/hashicorp/terraform/terraform/shadow_context.go
@@ -0,0 +1,158 @@
+package terraform
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+	"github.com/mitchellh/copystructure"
+)
+
+// newShadowContext creates a new context that will shadow the given context
+// when walking the graph. The resulting context should be used _only once_
+// for a graph walk.
+//
+// The returned Shadow should be closed after the graph walk with the
+// real context is complete. Errors from the shadow can be retrieved there.
+//
+// Most importantly, any operations done on the shadow context (the returned
+// context) will NEVER affect the real context. All structures are deep
+// copied, no real providers or resources are used, etc.
+func newShadowContext(c *Context) (*Context, *Context, Shadow) {
+	// Copy the targets
+	targetRaw, err := copystructure.Copy(c.targets)
+	if err != nil {
+		panic(err)
+	}
+
+	// Copy the variables
+	varRaw, err := copystructure.Copy(c.variables)
+	if err != nil {
+		panic(err)
+	}
+
+	// Copy the provider inputs
+	providerInputRaw, err := copystructure.Copy(c.providerInputConfig)
+	if err != nil {
+		panic(err)
+	}
+
+	// The factories
+	componentsReal, componentsShadow := newShadowComponentFactory(c.components)
+
+	// Create the shadow
+	shadow := &Context{
+		components: componentsShadow,
+		destroy:    c.destroy,
+		diff:       c.diff.DeepCopy(),
+		hooks:      nil,
+		meta:       c.meta,
+		module:     c.module,
+		state:      c.state.DeepCopy(),
+		targets:    targetRaw.([]string),
+		variables:  varRaw.(map[string]interface{}),
+
+		// NOTE(mitchellh): This is not going to work for shadows that are
+		// testing that input results in the proper end state. At the time
+		// of writing, input is not used in any state-changing graph
+		// walks anyways, so this checks nothing. We set it to this to avoid
+		// any panics but even a "nil" value worked here.
+		uiInput: new(MockUIInput),
+
+		// Hardcoded to 4 since parallelism in the shadow doesn't matter
+		// a ton since we're doing far less compared to the real side
+		// and our operations are MUCH faster.
+		parallelSem:         NewSemaphore(4),
+		providerInputConfig: providerInputRaw.(map[string]map[string]interface{}),
+	}
+
+	// Create the real context. This is effectively just a copy of
+	// the context given except we need to modify some of the values
+	// to point to the real side of a shadow so the shadow can compare values.
+	real := &Context{
+		// The fields below are changed.
+		components: componentsReal,
+
+		// The fields below are direct copies
+		destroy: c.destroy,
+		diff:    c.diff,
+		// diffLock - no copy
+		hooks:  c.hooks,
+		meta:   c.meta,
+		module: c.module,
+		sh:     c.sh,
+		state:  c.state,
+		// stateLock - no copy
+		targets:   c.targets,
+		uiInput:   c.uiInput,
+		variables: c.variables,
+
+		// l - no copy
+		parallelSem:         c.parallelSem,
+		providerInputConfig: c.providerInputConfig,
+		runContext:          c.runContext,
+		runContextCancel:    c.runContextCancel,
+		shadowErr:           c.shadowErr,
+	}
+
+	return real, shadow, &shadowContextCloser{
+		Components: componentsShadow,
+	}
+}
+
+// shadowContextVerify takes the real and shadow context and verifies they
+// have equal diffs and states.
+func shadowContextVerify(real, shadow *Context) error {
+	var result error
+
+	// The states compared must be pruned so they're minimal/clean
+	real.state.prune()
+	shadow.state.prune()
+
+	// Compare the states
+	if !real.state.Equal(shadow.state) {
+		result = multierror.Append(result, fmt.Errorf(
+			"Real and shadow states do not match! "+
+				"Real state:\n\n%s\n\n"+
+				"Shadow state:\n\n%s\n\n",
+			real.state, shadow.state))
+	}
+
+	// Compare the diffs
+	if !real.diff.Equal(shadow.diff) {
+		result = multierror.Append(result, fmt.Errorf(
+			"Real and shadow diffs do not match! "+
+				"Real diff:\n\n%s\n\n"+
+				"Shadow diff:\n\n%s\n\n",
+			real.diff, shadow.diff))
+	}
+
+	return result
+}
+
+// shadowContextCloser is the io.Closer returned by newShadowContext that
+// closes all the shadows and returns the results.
+type shadowContextCloser struct {
+	Components *shadowComponentFactory
+}
+
+// Close closes the shadow context.
+func (c *shadowContextCloser) CloseShadow() error {
+	return c.Components.CloseShadow()
+}
+
+func (c *shadowContextCloser) ShadowError() error {
+	err := c.Components.ShadowError()
+	if err == nil {
+		return nil
+	}
+
+	// This is a sad edge case: if the configuration contains uuid() at
+	// any point, we cannot reason aboyt the shadow execution. Tested
+	// with Context2Plan_shadowUuid.
+	if strings.Contains(err.Error(), "uuid()") {
+		err = nil
+	}
+
+	return err
+}