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Function: Advanced DECREMENT operation

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      Goal: Perform the Advanced DECREMENT operation where Eventing interacts with the Data service.

      • This function advancedDecrementOp merely demonstrates the Advanced DECREMENT operation.

      • Requires Eventing Storage (or metadata collection) and a "source" collection.

      • Needs a Binding of type "bucket alias" (as documented in the Scriptlet).

      • Will operate on any mutation and count down (decrement) the mutations subject to DCP dedup.

      • For more information refer to Advanced DECREMENT operation in the detailed documentation.

      • advancedDecrementOp

      • Input Data/Mutation

      • Output Data

      • Output Log

      // To run configure the settings for this Function, advancedDecrementOp, as follows:
      //
      // Version 7.0+
      //   "Listen to Location"
      //     bulk.data.source
      //   "Eventing Storage"
      //     rr100.eventing.metadata
      //   Binding(s)
      //    1. "binding type", "alias name...", "bucket.scope.collection", "Access"
      //       "bucket alias", "src_col",       "bulk.data.source",        "read and write"
      //
      // Version 6.6.1
      //   "Source Bucket"
      //     source
      //   "MetaData Bucket"
      //     metadata
      //   Binding(s)
      //    1. "binding type", "alias name...", "bucket",     "Access"
      //       "bucket alias", "src_col",       "source",     "read and write"
      
      function OnUpdate(doc, meta) {
          if (!meta.id.startsWith("dec:")) return;
          // log('input meta', meta);
          // log('input doc ', doc);
      
          // if doc.count doesn't exist it will be created
          var ctr_meta = {"id": "my_atomic_counter:1" };
          var result = couchbase.decrement(src_col,ctr_meta);
          if (result.success) {
              log('success adv. decrement: result',result);
          } else {
              log('failure adv. decrement: id',ctr_meta.id,'result',result);
          }
      }
      UPSERT INTO `bulk`.`data`.`source` (KEY,VALUE)
        VALUES ( "dec:1",  {"somekey":"someValue"} ),
        VALUES ( "dec:2",  {"somekey":"someValue"} ),
        VALUES ( "dec:3",  {"somekey":"someValue"} ),
        VALUES ( "dec:4",  {"somekey":"someValue"} ),
        VALUES ( "dec:5",  {"somekey":"someValue"} ),
        VALUES ( "dec:6",  {"somekey":"someValue"} ),
        VALUES ( "dec:7",  {"somekey":"someValue"} ),
        VALUES ( "dec:8",  {"somekey":"someValue"} ),
        VALUES ( "dec:9",  {"somekey":"someValue"} ),
        VALUES ( "dec:10", {"somekey":"someValue"} );

      We insert ten (10) documents and count the mutations via decrementing

      KEY: my_atomic_counter:1
      
      {
        "count": -10
      }
      2021-01-08T12:30:59.910-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-1},"meta":{"id":"my_atomic_counter:1","cas":"1610137859908960256"},"success":true}
      
      2021-01-08T12:30:59.910-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-2},"meta":{"id":"my_atomic_counter:1","cas":"1610137859909222400"},"success":true}
      
      2021-01-08T12:30:59.911-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-3},"meta":{"id":"my_atomic_counter:1","cas":"1610137859911385088"},"success":true}
      
      2021-01-08T12:30:59.931-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-4},"meta":{"id":"my_atomic_counter:1","cas":"1610137859929997312"},"success":true}
      
      2021-01-08T12:30:59.931-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-5},"meta":{"id":"my_atomic_counter:1","cas":"1610137859930193920"},"success":true}
      
      2021-01-08T12:30:59.932-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-6},"meta":{"id":"my_atomic_counter:1","cas":"1610137859932160000"},"success":true}
      
      2021-01-08T12:30:59.932-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-7},"meta":{"id":"my_atomic_counter:1","cas":"1610137859932356608"},"success":true}
      
      2021-01-08T12:30:59.948-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-8},"meta":{"id":"my_atomic_counter:1","cas":"1610137859946381312"},"success":true}
      
      2021-01-08T12:30:59.948-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-9},"meta":{"id":"my_atomic_counter:1","cas":"1610137859946708992"},"success":true}
      
      2021-01-08T12:30:59.948-08:00 [INFO] "success adv. increment: result"
      {"doc":{"count":-10},"meta":{"id":"my_atomic_counter:1","cas":"1610137859948412928"},"success":true}