Unable to read from s3 bucket using spark

Question

val spark = SparkSession
        .builder()
        .appName("try1")
        .master("local")
        .getOrCreate()

val df = spark.read
        .json("s3n://BUCKET-NAME/FOLDER/FILE.json")
        .select($"uid").show(5)

I have given the AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY as environment variables. I face below error while trying to read from S3.

Exception in thread "main" org.apache.hadoop.fs.s3.S3Exception: org.jets3t.service.S3ServiceException: S3 HEAD request failed for '/FOLDER%2FFILE.json' - ResponseCode=400, ResponseMessage=Bad Request

I suspect the error is caused due to "/" being converted to "%2F" by some internal function as the error shows '/FOLDER%2FFILE.json' instead of '/FOLDER/FILE.json'

Answer 1

Your spark (jvm) application cannot read environment variable if you don't tell it to, so a quick work around :

spark.sparkContext
     .hadoopConfiguration.set("fs.s3n.awsAccessKeyId", awsAccessKeyId)
spark.sparkContext
     .hadoopConfiguration.set("fs.s3n.awsSecretAccessKey", awsSecretAccessKey)

You'll also need to precise the s3 endpoint :

spark.sparkContext
     .hadoopConfiguration.set("fs.s3a.endpoint", "<<ENDPOINT>>");

To know more about what is AWS S3 Endpoint, refer to the following documentation :

• AWS Regions and Endpoints .

• Working with Amazon S3 Buckets .