64 lines
1.7 KiB
Go
64 lines
1.7 KiB
Go
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
|
|
}
|