Feature/auto edge httpfile

engine/resources/http.go

@@ -1036,6 +1036,84 @@ func (obj *HTTPFileRes) Cleanup() error {
 	return nil
 }
 
+// HTTPFileResAutoEdges holds the state of the auto edge generator.
+type HTTPFileResAutoEdges struct {
+	data    []engine.ResUID
+	pointer int
+	found   bool
+}
+
+// Next returns the next automatic edge.
+func (obj *HTTPFileResAutoEdges) Next() []engine.ResUID {
+	if obj.found {
+		return nil
+	}
+	if len(obj.data) == 0 {
+		return nil
+	}
+	value := obj.data[obj.pointer]
+	obj.pointer++
+	return []engine.ResUID{value}
+}
+
+// Test gets results of the earlier Next() call & returns if we should continue.
+func (obj *HTTPFileResAutoEdges) Test(input []bool) bool {
+	if len(obj.data) <= obj.pointer {
+		return false
+	}
+	if obj.found {
+		return false
+	}
+	if len(input) != 1 {
+		panic("Expecting a single value!")
+	}
+	if input[0] {
+		obj.found = true
+		return false
+	}
+	return true
+}
+
+// AutoEdges returns the automatic edges that this resource has based on its data.
+func (obj *HTTPFileRes) AutoEdges() (engine.AutoEdge, error) {
+	var data []engine.ResUID
+
+	// No automatic edges when using the Data field directly.
+	if obj.Data != "" {
+		return &HTTPFileResAutoEdges{
+			data:    data,
+			pointer: 0,
+			found:   false,
+		}, nil
+	}
+
+	// Skip edge creation if no path specified.
+	if obj.Path == "" {
+		return &HTTPFileResAutoEdges{
+			data:    data,
+			pointer: 0,
+			found:   false,
+		}, nil
+	}
+
+	// The file must exist before we can serve it.
+	var reversed = true
+	data = append(data, &FileUID{
+		BaseUID: engine.BaseUID{
+			Name:     obj.Name(),
+			Kind:     "file",
+			Reversed: &reversed,
+		},
+		path: obj.Path,
+	})
+
+	return &HTTPFileResAutoEdges{
+		data:    data,
+		pointer: 0,
+		found:   false,
+	}, nil
+}
+
 // Watch is the primary listener for this resource and it outputs events. This
 // particular one does absolutely nothing but block until we've received a done
 // signal.

examples/lang/http-edge0.mcl

@@ -0,0 +1,46 @@
+import "fmt"
+
+# This creates a set of test files with different configurations.
+file "/tmp/mgmt-test1.txt" {
+	content => "Hello from Test 1!",
+	state => $const.res.file.state.exists,
+}
+
+file "/tmp/mgmt-test2.txt" {
+	content => "Hello from Test 2!",
+	state => $const.res.file.state.exists,
+}
+
+# Create a test directory and its contents.
+file "/tmp/mgmt-test-dir/" {
+	state => $const.res.file.state.exists,
+}
+
+file "/tmp/mgmt-test-dir/index.txt" {
+	content => "Hello from Directory!",
+	state => $const.res.file.state.exists,
+}
+
+# Create an HTTP server to serve these files.
+http:server ":8080" {
+	address => ":8080",
+}
+
+# Serve multiple test files from the same server.
+http:file "/test1" {
+	path => "/tmp/mgmt-test1.txt",
+}
+
+http:file "/test2" {
+	path => "/tmp/mgmt-test2.txt",
+}
+
+# Configure directory serving.
+http:file "/dir/" {
+	path => "/tmp/mgmt-test-dir/",
+}
+
+# Serve a specific file from within the directory.
+http:file "/dir/index" {
+	path => "/tmp/mgmt-test-dir/index.txt",
+}