Check for circular dependencies in buildConfigs

pkg/build/registry/buildconfig/circular.go

@@ -0,0 +1,83 @@
+package buildconfig
+
+import (
+	"errors"
+
+	"github.com/openshift/origin/pkg/build/api"
+)
+
+// deps contains all image repositories mapped to their dependencies
+var deps = make(map[string]map[string]string)
+
+// circularDeps checks for circular dependencies in build configurations
+func circularDeps(config *api.BuildConfig) bool {
+	if config.Parameters.Output.To == nil || len(config.Triggers) == 0 {
+		return false
+	}
+
+	// Create output spec
+	if len(config.Parameters.Output.To.Namespace) == 0 {
+		config.Parameters.Output.To.Namespace = config.Namespace
+	}
+	if len(config.Parameters.Output.Tag) == 0 {
+		config.Parameters.Output.Tag = "latest"
+	}
+	to := config.Parameters.Output.To.Namespace + "/" + config.Parameters.Output.To.Name + ":" + config.Parameters.Output.Tag
+
+	for _, tr := range config.Triggers {
+		if tr.ImageChange == nil {
+			continue
+		}
+
+		// Create input spec
+		if len(tr.ImageChange.From.Namespace) == 0 {
+			tr.ImageChange.From.Namespace = config.Namespace
+		}
+		if len(tr.ImageChange.Tag) == 0 {
+			tr.ImageChange.Tag = "latest"
+		}
+		from := tr.ImageChange.From.Namespace + "/" + tr.ImageChange.From.Name + ":" + tr.ImageChange.Tag
+
+		// Check for any conflicts in dependencies
+		if err := findConflicts(from, to); err != nil {
+			return true
+		}
+		// The trigger is valid, add the relationship in deps
+		if _, ok := deps[from]; !ok {
+			deps[from] = make(map[string]string)
+		}
+		fromDeps := deps[from]
+		fromDeps[to] = config.Name
+	}
+
+	return false
+}
+
+// findConflicts traces if there are any conflicts in the dependencies
+// of From and To in a build configuration
+func findConflicts(from, to string) error {
+	toDeps := deps[to]
+
+	// Check the dependencies of the dependency we want to add
+	for toDep := range toDeps {
+		if from == toDep {
+			// From already depends on To
+			return errors.New("circular dependencies in buildConfigs")
+		}
+		if err := findConflicts(from, toDep); err != nil {
+			// From already depends on another repo that depends on To
+			return err
+		}
+	}
+	return nil
+}
+
+func deleteFromDeps(id string) {
+	for _, dep := range deps {
+		for repo, cfgName := range dep {
+			if cfgName == id {
+				delete(dep, repo)
+			}
+		}
+	}
+}