63 lines
1.9 KiB
Go
63 lines
1.9 KiB
Go
package terraform
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import (
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"log"
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"github.com/hashicorp/terraform/dag"
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)
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// GraphTransformer is the interface that transformers implement. This
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// interface is only for transforms that need entire graph visibility.
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type GraphTransformer interface {
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Transform(*Graph) error
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}
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// GraphVertexTransformer is an interface that transforms a single
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// Vertex within with graph. This is a specialization of GraphTransformer
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// that makes it easy to do vertex replacement.
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//
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// The GraphTransformer that runs through the GraphVertexTransformers is
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// VertexTransformer.
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type GraphVertexTransformer interface {
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Transform(dag.Vertex) (dag.Vertex, error)
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}
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// GraphTransformIf is a helper function that conditionally returns a
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// GraphTransformer given. This is useful for calling inline a sequence
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// of transforms without having to split it up into multiple append() calls.
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func GraphTransformIf(f func() bool, then GraphTransformer) GraphTransformer {
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if f() {
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return then
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}
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return nil
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}
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type graphTransformerMulti struct {
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Transforms []GraphTransformer
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}
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func (t *graphTransformerMulti) Transform(g *Graph) error {
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var lastStepStr string
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for _, t := range t.Transforms {
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log.Printf("[TRACE] (graphTransformerMulti) Executing graph transform %T", t)
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if err := t.Transform(g); err != nil {
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return err
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}
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if thisStepStr := g.StringWithNodeTypes(); thisStepStr != lastStepStr {
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log.Printf("[TRACE] (graphTransformerMulti) Completed graph transform %T with new graph:\n%s------", t, thisStepStr)
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lastStepStr = thisStepStr
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} else {
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log.Printf("[TRACE] (graphTransformerMulti) Completed graph transform %T (no changes)", t)
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}
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}
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return nil
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}
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// GraphTransformMulti combines multiple graph transformers into a single
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// GraphTransformer that runs all the individual graph transformers.
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func GraphTransformMulti(ts ...GraphTransformer) GraphTransformer {
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return &graphTransformerMulti{Transforms: ts}
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}
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