1 files changed, 63 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/terraform/terraform/eval.go b/vendor/github.com/hashicorp/terraform/terraform/eval.go
new file mode 100644
index 00000000..3cb088a2
--- /dev/null
+++ b/vendor/github.com/hashicorp/terraform/terraform/eval.go
@@ -0,0 +1,63 @@
+package terraform
+
+import (
+	"log"
+	"strings"
+)
+
+// EvalNode is the interface that must be implemented by graph nodes to
+// evaluate/execute.
+type EvalNode interface {
+	// Eval evaluates this node with the given context. The second parameter
+	// are the argument values. These will match in order and 1-1 with the
+	// results of the Args() return value.
+	Eval(EvalContext) (interface{}, error)
+}
+
+// GraphNodeEvalable is the interface that graph nodes must implement
+// to enable valuation.
+type GraphNodeEvalable interface {
+	EvalTree() EvalNode
+}
+
+// EvalEarlyExitError is a special error return value that can be returned
+// by eval nodes that does an early exit.
+type EvalEarlyExitError struct{}
+
+func (EvalEarlyExitError) Error() string { return "early exit" }
+
+// Eval evaluates the given EvalNode with the given context, properly
+// evaluating all args in the correct order.
+func Eval(n EvalNode, ctx EvalContext) (interface{}, error) {
+	// Call the lower level eval which doesn't understand early exit,
+	// and if we early exit, it isn't an error.
+	result, err := EvalRaw(n, ctx)
+	if err != nil {
+		if _, ok := err.(EvalEarlyExitError); ok {
+			return nil, nil
+		}
+	}
+
+	return result, err
+}
+
+// EvalRaw is like Eval except that it returns all errors, even if they
+// signal something normal such as EvalEarlyExitError.
+func EvalRaw(n EvalNode, ctx EvalContext) (interface{}, error) {
+	path := "unknown"
+	if ctx != nil {
+		path = strings.Join(ctx.Path(), ".")
+	}
+
+	log.Printf("[DEBUG] %s: eval: %T", path, n)
+	output, err := n.Eval(ctx)
+	if err != nil {
+		if _, ok := err.(EvalEarlyExitError); ok {
+			log.Printf("[DEBUG] %s: eval: %T, err: %s", path, n, err)
+		} else {
+			log.Printf("[ERROR] %s: eval: %T, err: %s", path, n, err)
+		}
+	}
+
+	return output, err
+}