Merge pull request kubernetes#108 from astefanutti/pr-gc

UPSTREAM: <carry>: garbage collector monitors syncing
ezrasilvera · Nov 9, 2022 · 522b775 · 522b775
2 parents 309ae77 + 0526091
commit 522b775
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Showing 6 changed files with 351 additions and 89 deletions.
diff --git a/hack/kcp/garbage_collector_patch.go b/hack/kcp/garbage_collector_patch.go
@@ -0,0 +1,109 @@
+/*
+Copyright 2022 The KCP Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/parser"
+	"go/token"
+	"log"
+	"strings"
+)
+
+/*
+Process:
+
+1. go run ./hack/kcp/garbage_collector_patch.go > pkg/controller/garbagecollector/garbagecollector_patch.go
+(you may need to add -mod=readonly)
+
+2. goimports -w pkg/controller/garbagecollector/garbagecollector_patch.go
+
+3. reapply patch for kcp to pkg/controller/garbagecollector/garbagecollector_patch.go
+*/
+
+func main() {
+	fileSet := token.NewFileSet()
+
+	file, err := parser.ParseFile(fileSet, "pkg/controller/garbagecollector/garbagecollector.go", nil, parser.ParseComments)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// n stores a reference to the node for the function declaration for Sync
+	var n ast.Node
+
+	ast.Inspect(file, func(node ast.Node) bool {
+		switch x := node.(type) {
+		case *ast.FuncDecl:
+			if x.Name.Name == "Sync" {
+				// Store the reference
+				n = node
+				// Stop further inspection
+				return false
+			}
+		}
+
+		// Continue recursing
+		return true
+	})
+
+	startLine := fileSet.Position(n.Pos()).Line
+	endLine := fileSet.Position(n.End()).Line
+
+	// To preserve the comments from within the function body itself, we have to write out the entire file to a buffer,
+	// then extract only the lines we care about (the function body).
+	var buf bytes.Buffer
+	if err := format.Node(&buf, fileSet, file); err != nil {
+		log.Fatal(err)
+	}
+
+	// Convert the buffer to a slice of lines, so we can grab the portion we want
+	var lines []string
+	scanner := bufio.NewScanner(&buf)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(`/*
+Copyright 2022 The KCP Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package garbagecollector
+`)
+
+	// Finally, print the line range we need
+	fmt.Println(strings.Join(lines[startLine-1:endLine], "\n"))
+}