122 lines
3.5 KiB
Go
122 lines
3.5 KiB
Go
package terraform
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import (
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"fmt"
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"log"
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"github.com/hashicorp/terraform/tfdiags"
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"github.com/hashicorp/terraform/addrs"
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"github.com/hashicorp/terraform/dag"
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)
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// Graph represents the graph that Terraform uses to represent resources
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// and their dependencies.
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type Graph struct {
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// Graph is the actual DAG. This is embedded so you can call the DAG
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// methods directly.
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dag.AcyclicGraph
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// Path is the path in the module tree that this Graph represents.
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Path addrs.ModuleInstance
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}
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func (g *Graph) DirectedGraph() dag.Grapher {
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return &g.AcyclicGraph
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}
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// Walk walks the graph with the given walker for callbacks. The graph
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// will be walked with full parallelism, so the walker should expect
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// to be called in concurrently.
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func (g *Graph) Walk(walker GraphWalker) tfdiags.Diagnostics {
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return g.walk(walker)
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}
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func (g *Graph) walk(walker GraphWalker) tfdiags.Diagnostics {
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// The callbacks for enter/exiting a graph
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ctx := walker.EnterPath(g.Path)
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defer walker.ExitPath(g.Path)
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// Walk the graph.
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var walkFn dag.WalkFunc
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walkFn = func(v dag.Vertex) (diags tfdiags.Diagnostics) {
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log.Printf("[TRACE] vertex %q: starting visit (%T)", dag.VertexName(v), v)
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defer func() {
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log.Printf("[TRACE] vertex %q: visit complete", dag.VertexName(v))
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}()
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walker.EnterVertex(v)
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defer walker.ExitVertex(v, diags)
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// vertexCtx is the context that we use when evaluating. This
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// is normally the context of our graph but can be overridden
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// with a GraphNodeSubPath impl.
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vertexCtx := ctx
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if pn, ok := v.(GraphNodeSubPath); ok && len(pn.Path()) > 0 {
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vertexCtx = walker.EnterPath(pn.Path())
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defer walker.ExitPath(pn.Path())
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}
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// If the node is eval-able, then evaluate it.
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if ev, ok := v.(GraphNodeEvalable); ok {
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tree := ev.EvalTree()
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if tree == nil {
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panic(fmt.Sprintf("%q (%T): nil eval tree", dag.VertexName(v), v))
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}
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// Allow the walker to change our tree if needed. Eval,
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// then callback with the output.
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log.Printf("[TRACE] vertex %q: evaluating", dag.VertexName(v))
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tree = walker.EnterEvalTree(v, tree)
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output, err := Eval(tree, vertexCtx)
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diags = diags.Append(walker.ExitEvalTree(v, output, err))
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if diags.HasErrors() {
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return
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}
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}
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// If the node is dynamically expanded, then expand it
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if ev, ok := v.(GraphNodeDynamicExpandable); ok {
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log.Printf("[TRACE] vertex %q: expanding dynamic subgraph", dag.VertexName(v))
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g, err := ev.DynamicExpand(vertexCtx)
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if err != nil {
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diags = diags.Append(err)
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return
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}
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if g != nil {
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// Walk the subgraph
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log.Printf("[TRACE] vertex %q: entering dynamic subgraph", dag.VertexName(v))
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subDiags := g.walk(walker)
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diags = diags.Append(subDiags)
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if subDiags.HasErrors() {
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log.Printf("[TRACE] vertex %q: dynamic subgraph encountered errors", dag.VertexName(v))
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return
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}
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log.Printf("[TRACE] vertex %q: dynamic subgraph completed successfully", dag.VertexName(v))
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} else {
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log.Printf("[TRACE] vertex %q: produced no dynamic subgraph", dag.VertexName(v))
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}
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}
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// If the node has a subgraph, then walk the subgraph
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if sn, ok := v.(GraphNodeSubgraph); ok {
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log.Printf("[TRACE] vertex %q: entering static subgraph", dag.VertexName(v))
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subDiags := sn.Subgraph().(*Graph).walk(walker)
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if subDiags.HasErrors() {
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log.Printf("[TRACE] vertex %q: static subgraph encountered errors", dag.VertexName(v))
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return
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}
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log.Printf("[TRACE] vertex %q: static subgraph completed successfully", dag.VertexName(v))
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}
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return
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}
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return g.AcyclicGraph.Walk(walkFn)
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}
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