1 files changed, 48 insertions, 0 deletions
diff --git a/atomictemp/atomictemp.go b/atomictemp/atomictemp.go
new file mode 100644
index 0000000..b56d095
--- /dev/null
+++ b/atomictemp/atomictemp.go
@@ -0,0 +1,48 @@
+// Create a temporary file in the directory of the given destination
+// file, then rename the temporary file over the destination file if
+// writes to the temporary file complete without error.
+//
+// Used to atomically update files.
+//
+// Note: This is not guaranteed and depends on the sync semantics of the
+// underlying filesystem.
+package atomictemp
+
+import (
+  "io"
+  "os"
+  "path/filepath"
+)
+
+// Create a temporary file in the directory of the given destination
+// file, then rename the temporary file over the destination file if
+// writes to the temporary file complete without error.
+//
+// Used to atomically update files.
+//
+// Note: This is not guaranteed and depends on the sync semantics of the
+// underlying filesystem.
+func Create(dstPath string, fn func(io.Writer) error) error {
+  // open temp output file
+  f, err := os.CreateTemp(filepath.Dir(dstPath), "")
+  if err != nil {
+    return err
+  }
+
+  // build absolute path to temporary file
+  // tmpPath := filepath.Join(filepath.Dir(dstPath), f.Name())
+  defer os.Remove(f.Name())
+
+  // invoke callback
+  if err = fn(f); err != nil {
+    return err
+  }
+
+  // close temp file
+  if err = f.Close(); err != nil {
+    return err
+  }
+
+  // rename to destination file, return result
+  return os.Rename(f.Name(), dstPath)
+}