add skate-derive-key -F for fixed field

1 files changed, 26 insertions, 4 deletions

diff --git a/skate/cmd/skate-derive-key/main.go b/skate/cmd/skate-derive-key/main.go
index 653e258..b5b13f2 100644
--- a/skate/cmd/skate-derive-key/main.go
+++ b/skate/cmd/skate-derive-key/main.go
@@ -30,10 +30,12 @@ import (
 
 	"git.archive.org/martin/cgraph/skate"
 	"git.archive.org/martin/cgraph/skate/parallel"
+	jsoniter "github.com/json-iterator/go"
 )
 
 var (
-	keyFuncName   = flag.String("f", "tsand", "key function name, other: title, tnorm, tnysi, tsand, ident")
+	keyFuncName   = flag.String("f", "tsand", "key function name, other: title, tnorm, tnysi, tsand")
+	fixedField    = flag.String("F", "", "extract value from a fixed top level field, e.g. source_release_ident, ...")
 	numWorkers    = flag.Int("w", runtime.NumCPU(), "number of workers")
 	batchSize     = flag.Int("b", 50000, "batch size")
 	verbose       = flag.Bool("verbose", false, "show progress")
@@ -47,16 +49,36 @@ var (
 		"tnorm": skate.KeyTitleNormalized,
 		"tnysi": skate.KeyTitleNysiis,
 		"tsand": skate.KeyTitleSandcrawler,
-		"ident": skate.KeySourceIdent,
 	}
 	keyFunc skate.IdentifierKeyFunc
 	ok      bool
+	json    = jsoniter.ConfigCompatibleWithStandardLibrary
 )
 
 func main() {
 	flag.Parse()
-	if keyFunc, ok = keyOpts[*keyFuncName]; !ok {
-		log.Fatal("invalid key func")
+	if *fixedField != "" {
+		// We want this, because from biblioref we wanted source_release_ident,
+		// from refs release_ident, etc.
+		keyFunc = func(p []byte) (id string, key string, err error) {
+			var doc map[string]interface{}
+			if err = json.Unmarshal(p, &doc); err != nil {
+				return
+			}
+			v, ok := doc[*fixedField]
+			if !ok {
+				return "", "", nil
+			}
+			s, ok := v.(string)
+			if !ok {
+				return "", "", nil
+			}
+			return "", s, nil
+		}
+	} else {
+		if keyFunc, ok = keyOpts[*keyFuncName]; !ok {
+			log.Fatal("invalid key func")
+		}
 	}
 	if *logFile != "" {
 		f, err := os.OpenFile(*logFile, os.O_CREATE|os.O_APPEND, 0644)