Better output of progress

Author: Jamie Curnow

README.md

@@ -17,9 +17,9 @@ Any pre-existing keys on DESTINATION that are not on SOURCE will remain untouche
 ## Usage
 
 ```bash
-Usage: redis-migrator --source-host SOURCE-HOST --destination-host DESTINATION-HOST
-  [--source-port SOURCE-PORT] [--source-db SOURCE-DB] [--source-user SOURCE-USER]
-  [--source-pass SOURCE-PASS] [--destination-port DESTINATION-PORT]
+Usage: redis-migrator --source-host SOURCE-HOST [--source-port SOURCE-PORT]
+  [--source-db SOURCE-DB] [--source-user SOURCE-USER] [--source-pass SOURCE-PASS]
+  --destination-host DESTINATION-HOST [--destination-port DESTINATION-PORT]
   [--destination-db DESTINATION-DB] [--destination-user DESTINATION-USER]
   [--destination-pass DESTINATION-PASS] [--source-filter SOURCE-FILTER]
   [--destination-prefix DESTINATION-PREFIX] [--verbose]
@@ -51,6 +51,7 @@ Options:
                          destination key prefix to prepend
   --verbose, -v          Print a lot more info
   --help, -h             display this help and exit
+  --version              display version and exit
 ```
 
 ## Install
@@ -73,3 +74,44 @@ git clone https://github.com/jc21/redis-migrator && cd redis-migrator
 go build -ldflags="-X main.version=1.0.1" -o bin/redis-migrator cmd/redis-migrator/main.go
 ./bin/redis-migrator -h
 ```
+
+
+## Real world example
+
+Copying data from one db to another on the same instance. This is a production instance
+where the keys were expiring mid-way through the migration, hence why the total
+number of keys migrated doesn't match the initial count.
+
+```bash
+time redis-migrator --source-host 127.0.0.1 --source-db 0 --destination-host 127.0.0.1 --destination-db 1
+SOURCE:
+  Server:   127.0.0.1:6379
+  DB Index: 0
+  Auth:     None
+DESTINATION:
+  Server:   127.0.0.1:6379
+  DB Index: 1
+  Auth:     None
+2021-02-22 07:08:37 INFO => Source has 622028 keys
+2021-02-22 07:08:37 INFO => Destination has 0 keys
+2021-02-22 07:08:37 INFO => Found 622028 keys on SOURCE with Key filter: *
+2021-02-22 07:08:37 INFO => Migration running, each dot is ~1,000 keys
+.......... .......... .......... .......... .......... 8% (50012 / 622028)
+.......... .......... .......... .......... .......... 16% (100028 / 622028)
+.......... .......... .......... .......... .......... 24% (150037 / 622028)
+.......... .......... .......... .......... .......... 32% (200046 / 622028)
+.......... .......... .......... .......... .......... 40% (250058 / 622028)
+.......... .......... .......... .......... .......... 48% (300073 / 622028)
+.......... .......... .......... .......... .......... 56% (350084 / 622028)
+.......... .......... .......... .......... .......... 64% (400090 / 622028)
+.......... .......... .......... .......... .......... 72% (450102 / 622028)
+.......... .......... .......... .......... .......... 80% (500113 / 622028)
+.......... .......... .......... .......... .......... 88% (550127 / 622028)
+.......... .......... .......... .......... .......... 96% (600147 / 622028)
+.......... .......... ..
+2021-02-22 07:16:33 INFO => Migration completed with 622004 keys, 0 skipped :)
+
+real    7m55.358s
+user    0m52.892s
+sys     4m32.788s
+```

pkg/migrator/migrate.go

@@ -26,14 +26,15 @@ func DoMigration(sourceClient, destinationClient *redis.Client, keyFilter, keyPr
 		os.Exit(1)
 	}
 
-	logger.Info("Migration running, each dot is 1,000 keys, each row is 50,000 keys")
+	logger.Info("Migration running, each dot is ~1,000 keys")
 
 	var cursor uint64
 	var n int
 
 	counter := 0
 	skipped := 0
 	dots := 0
+	var percentage int64
 
 	for {
 		var keys []string
@@ -76,11 +77,16 @@ func DoMigration(sourceClient, destinationClient *redis.Client, keyFilter, keyPr
 		fmt.Print(".")
 		dots++
 		n += len(keys)
-		if cursor == 0 {
-			break
+		if dots%10 == 0 {
+			fmt.Print(" ")
 		}
 		if dots%50 == 0 {
-			fmt.Print("\n")
+			// Print a percentage
+			percentage = int64(math.Round((float64(counter) / float64(size)) * 100))
+			fmt.Printf("%d%% (%d / %d)\n", percentage, counter, size)
+		}
+		if cursor == 0 {
+			break
 		}
 	}