go - Golang PutItem DynamoDB: Runtime Error invalid memory address or nil pointer dereference -

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new programming golang , aws. block of code in function, trying out creating new table , writing values using aws dynamodb. creation successful, program crashes when write happens. not sure why..i'd grateful if me out! 

**logs**:  2015/07/22 15:46:46 tablestatus: 0xc208193cb0 2015/07/22 15:46:46 end 2015/07/22 15:46:48 sleep 2: before write 2015/07/22 15:46:48 before defining input panic: runtime error: invalid memory address or nil pointer dereference [signal 0xb code=0x1 addr=0x20 pc=0x401b28]  **code block:**  {     log.println("entry+++")         cfg := aws.defaultconfig          svc := dynamodb.new(cfg)          tabledefinition := &dynamodb.createtableinput{             tablename:            aws.string("table1"),             attributedefinitions: make([]*dynamodb.attributedefinition, 1, 1),             keyschema:            make([]*dynamodb.keyschemaelement, 1, 1),             provisionedthroughput: &dynamodb.provisionedthroughput{                 readcapacityunits:  aws.long(1),                 writecapacityunits: aws.long(1),             },         }          tabledefinition.keyschema[0] = &dynamodb.keyschemaelement{             attributename: aws.string("batch_id"),             keytype:       aws.string("hash"),         }         tabledefinition.attributedefinitions[0] = &dynamodb.attributedefinition{             attributename: aws.string("batch_id"),             attributetype: aws.string("s"),         }          resp, err := svc.createtable(tabledefinition)         log.println("after createtable---")          if err != nil {             log.println("create table failed", err.error())             return         }         if resp != nil && resp.tabledescription != nil {             log.println(                 "tablestatus:", resp.tabledescription.tablestatus)         }          log.println("end")         //some time before createtable transaction gets committed.          time.sleep(2 * time.second)         log.println("sleep 2 before write")          testa := "batch_1" //value written db         // testb := "batch_name"         // testc := "530"         // testd := "sample-keyy-98"          log.println("before defining input")         input := &dynamodb.putiteminput{             tablename: aws.string("table1"),             item: map[string]*dynamodb.attributevalue{                 "batch_id": &dynamodb.attributevalue{                     s: aws.string(testa),                 },                 // "name": &dynamodb.attributevalue{                 //  s: aws.string(testb),                 // },             },         }          _, err2 := svc.putitem(input)     }

it helpful if show stack trace of error. until error occurs when try access member of uninitialized variable. example if error comming @ following line

a := b.c

then need check if b initialized properly. value of b nil hence nil pointer dereference.


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