[GRAPH] Fix #158, add triggering files, add tests

Based on my research, the panic came from the call to graph.Walk
within graph.Copy.  With help from @BrianHicks, I was able to:

1. fix the bug with new, simpler logic for graph.Copy
2. those hcl files that triggered the race condition
3. add a blackbox test, which works with the hcl files
4. add a benchmark test case for testing parallel copies

blackbox/test_graph_dependencies.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+ROOT=$(pwd)
+
+TMP=$(mktemp -d -t converge.graph_dependencies.XXXXXXXXXX)
+function finish {
+    rm -rf $TMP
+}
+trap finish EXIT
+
+pushd $TMP
+
+for src in ${ROOT}/samples/dependencies/*.hcl; do
+	b=$(basename $src)
+	echo "starting repetative graph test for ${b}"
+	for i in `seq 1 5`; do 
+		${ROOT}/converge graph -l "WARN" ${src} >/dev/null
+	done
+	echo "success: no errors generating dependencies for ${b}"
+done
+echo "success: no errors for any .hcl files"
+
+popd

graph/graph.go

@@ -422,19 +422,12 @@ func (g *Graph) RootFirstTransform(ctx context.Context, cb TransformFunc) (*Grap
 func (g *Graph) Copy() *Graph {
 	out := New()
 
-	err := g.Walk(
-		context.Background(),
-		func(id string, val interface{}) error {
-			out.Add(id, val)
-			for _, edge := range g.DownEdges(id) {
-				out.inner.Connect(edge)
-			}
+	for _, v := range g.Vertices() {
+		out.Add(v, g.Get(v))
+	}
 
-			return nil
-		},
-	)
-	if err != nil {
-		panic(err)
+	for _, e := range g.inner.Edges() {
+		out.inner.Connect(e)
 	}
 
 	return out

graph/graph_test.go

@@ -59,6 +59,15 @@ func BenchmarkAddThenGet(b *testing.B) {
 	})
 }
 
+func BenchmarkCopyParallel(b *testing.B) {
+	g := graph.New()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			g.Copy()
+		}
+	})
+}
+
 func TestRemove(t *testing.T) {
 	// Remove should remove a vertex
 	t.Parallel()

samples/dependencies/cert.hcl

@@ -0,0 +1,28 @@
+# cert
+param "cn" {}
+param "name" {}
+param "ca_crt" {
+  default = "ca.crt"
+}
+param "ca_key" {
+  default = "ca.key"
+}
+task "directory" {
+  check = "test -d ssl"
+  apply = "mkdir ssl"
+}
+task "key" {
+  check = "test -f ssl/{{param `name`}}.key"
+  apply = "cd ssl; openssl genrsa -out {{param `name`}}.key 2048"
+  depends = ["task.directory"]
+}
+task "csr" {
+  check = "test -f ssl/{{param `name`}}.csr"
+  apply = "cd ssl; openssl req -new -key {{param `name`}}.key --subj \"/CN={{param `cn`}}\" -out {{param `name`}}.csr"
+  depends = ["task.key"]
+}
+task "crt" {
+  check = "test -f ssl/{{param `name`}}.crt"
+  apply = "cd ssl; openssl x509 -req -in {{param `name`}}.csr -CA {{param `ca_crt`}} -CAkey {{param `ca_key`}} -CAcreateserial -out {{param `name`}}.crt -days 10000"
+  depends = ["task.csr"]
+}

samples/dependencies/k8sCerts.hcl

@@ -0,0 +1,39 @@
+# create certificates for a Kubernetes cluster
+param "master_ip" {}
+
+task "directory" {
+  check = "test -d ssl"
+  apply = "mkdir ssl"
+}
+
+task "ca.key" {
+  check = "test -f ssl/ca.key"
+  apply = "cd ssl; openssl genrsa -out ca.key 2048"
+
+  depends = ["task.directory"]
+}
+
+task "ca.crt" {
+  check = "test -f ssl/ca.crt"
+  apply = "cd ssl; openssl req -x509 -new -nodes -key ca.key -subj \"/CN={{param `master_ip`}}\" -days 10000 -out ca.crt"
+
+  depends = ["task.ca.key"]
+}
+
+module "cert.hcl" "server" {
+  params {
+    cn   = "{{param `master_ip`}}"
+    name = "server"
+  }
+
+  depends = ["task.ca.key", "task.ca.crt"]
+}
+
+module "cert.hcl" "kubelet" {
+  params {
+    cn   = "{{param `master_ip`}}"
+    name = "kubelet"
+  }
+
+  depends = ["task.ca.key", "task.ca.crt"]
+}

samples/dependencies/simpleShell.hcl

@@ -0,0 +1,21 @@
+param "working-directory" {
+  default = "/tmp/converge-testing"
+}
+
+param "test-file" {
+  default = "{{param `working-directory`}}/test-file"
+}
+
+task "directory" {
+  check = "[ -d \"{{param `working-directory`}}\" ] && echo present || (echo absent && exit 1)"
+  apply = "mkdir -p {{param `working-directory`}}"
+}
+
+task "touch-file" {
+  interpreter = "/bin/bash"
+  check_flags = ["-n"]
+
+  check = "cat {{param `test-file`}} | grep \"hello\""
+  apply = "echo hello > {{param `test-file`}}"
+  depends = ["task.directory"]
+}