internal/ci: use writefs

Signed-off-by: Paul Jolly <[email protected]>
Change-Id: Ia9203e2138ad74947ba49614df3298d84b7aa860
Dispatch-Trailer: {"type":"trybot","CL":1170145,"patchset":1,"ref":"refs/changes/45/1170145/1","targetBranch":"alpha"}

internal/ci/github/workflows.cue

@@ -15,6 +15,12 @@
 // package github declares the workflows for this project.
 package github
 
+import (
+	"encoding/yaml"
+
+	"github.com/cue-lang/cuelang.org/internal/ci/base"
+)
+
 // Note: the name of the workflows (and hence the corresponding .yml filenames)
 // correspond to the environment variable names for gerritstatusupdater.
 // Therefore, this filename must only be change in combination with also
@@ -55,3 +61,31 @@ _linuxWorkflow: {
 dummyDispatch: _repo.#dispatch & {
 	type: _repo.trybot.key
 }
+
+// #writefs mirrors the type of the arguments expected by
+// internal/cmd/writefs
+#writefs: {
+	Remove: [...string]
+	Create: [string]: {
+		Type:     "symlink" | *"file"
+		Contents: *"" | string
+	}
+}
+
+fs: #writefs & {
+	// TODO: do not hardcode this to ci_tool
+	let donotedit = base.doNotEditMessage & {#generatedBy: "internal/ci/ci_tool.cue", _}
+
+	Remove: [
+		"../../.github/workflows/*.yml",
+	]
+
+	Create: {
+		for _name, _workflow in workflows {
+			"\(_name).yml": {
+				Contents: "# \(donotedit)\n\n\(yaml.Marshal(_workflow))"
+			}
+		}
+		"../../codereview.cfg": 
+	}
+}

internal/cmd/writefs/main.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"log"
+	"os"
+	"path/filepath"
+)
+
+type file struct {
+	Type string
+
+	// If typ == "symlink" this is the filepath of the target
+	// otherwise it is the Contents of the file
+	Contents string
+}
+
+type args struct {
+	// Remove is a list of globs of files to remove. File
+	// removal happens before file creation.
+	Remove []string
+
+	// Create is a map of file path (in Unix format) to contents.
+	Create map[string]file
+}
+
+func main() {
+	var todo args
+	dec := json.NewDecoder(os.Stdin)
+	if err := dec.Decode(&todo); err != nil {
+		log.Fatalf("failed to decode arguments from stdin: %v", err)
+	}
+	for _, glob := range todo.Remove {
+		files, err := filepath.Glob(glob)
+		if err != nil {
+			log.Fatalf("failed to glob %q: %v", glob, err)
+		}
+		if len(files) == 0 {
+			continue
+		}
+		for _, f := range files {
+			if err := os.Remove(f); err != nil {
+				log.Fatalf("failed to remove %s: %v", f, err)
+			}
+		}
+	}
+	for fp, f := range todo.Create {
+		fp = filepath.FromSlash(fp)
+		dir := filepath.Dir(fp)
+		if err := os.MkdirAll(dir, 0o777); err != nil {
+			log.Fatalf("failed to mkdir %s: %v", dir, err)
+		}
+		switch f.Type {
+		case "symlink":
+			target := filepath.FromSlash(f.Contents)
+			actualTarget, err := os.Readlink(fp)
+			if err == nil && actualTarget == target {
+				continue
+			}
+			if err := os.Symlink(target, fp); err != nil {
+				log.Fatalf("failed to symlink %s -> %s: %v", fp, target, err)
+			}
+		case "file":
+			// If we have a .json file, normalise the contents first
+			// as a special case.
+			//
+			// TODO: this actually belongs as an option in CUE.
+			contents := []byte(f.Contents)
+			if filepath.Ext(fp) == ".json" {
+				var i any
+				err := json.Unmarshal(contents, &i)
+				if err == nil {
+					var b bytes.Buffer
+					enc := json.NewEncoder(&b)
+					enc.SetEscapeHTML(false)
+					enc.SetIndent("", "    ")
+					if err := enc.Encode(i); err == nil {
+						// Add a trailing newline
+						contents = b.Bytes()
+					}
+				}
+			}
+			if err := os.WriteFile(fp, []byte(contents), 0o666); err != nil {
+				log.Fatalf("failed to write file %s: %v", fp, err)
+			}
+		}
+	}
+}