awsS3Sign.sh

#!/bin/bash -e
bucket=$1
shift
filename=$1
shift
contentType=$1
shift

# Grab the config values
configFile="/path/to/.aws/credentials"
eval $(cat $configFile | grep -P "^\w+=.*$")

# Calculate the signature.
resource="/${bucket}/${filename}"
dateValue=$(date -R)
stringToSign="PUT\n\n${contentType}\n${dateValue}\n${resource}"
signature=$(echo -en ${stringToSign} | openssl sha1 -hmac ${aws_secret_access_key} -binary | base64)

# Output the Date and Authorization headers values
echo "${dateValue}|AWS ${aws_access_key_id}:${signature}"

GatlingsS3Upload.scala

// Gatling upload of file (blobFilename, blobPath, blobMimeType) into bucket with a PUT request (limited to 5g)
          .exec(session => {
            val script = "/path/to/awsS3Sign.sh " +
              bucket + " " + session("blobFilename").as[String] + " " + session("blobMimeType").as[String]
            val scriptOutput: String = script.!!
            val dateHeader: String = scriptOutput.substring(0, scriptOutput.indexOf('|'))
            val authorizationHeader: String = scriptOutput.substring(scriptOutput.indexOf('|') + 1).trim()
            println("Upload " + session("blobFilename").as[String])
            session.set("awsDate", dateHeader)
              .set("awsAuth", authorizationHeader)
          })
          .exec(
            http("s3 upload")
              .put("https://" + bucket + ".s3.amazonaws.com/${blobFilename}")
              .header("Host", bucket + ".s3.amazonaws.com")
              .header("Date", "${awsDate}")
              .header("Content-Type", "${blobMimeType}")
              .header("Authorization", "${awsAuth}")
              .body(RawFileBody("${blobPath}"))
              .check(status.in(200))
          )
// Disable the cache because S3 does not handle the If-None-Match header
 val httpProtocol = http.disableCaching