title: boto3 file_upload does it check if file exists
body: <p>I was looking through the boto3 documentation and could not find if it natively supports a check to see if the file already exists in s3 and if not do not try and re-upload.</p>
  
  <p>Here's what I have working:</p>
  
  <pre><code>import boto3
  
  s3_client = boto3.client('s3')
  s3_bucket = 'bucketName'
  s3_folder = 'folder1234/'
  temp_log_dir = "tempLogs/"
  
  
  s3_client.upload_file(temp_log_dir + file_name, s3_bucket, s3_folder + file_name)
  </code></pre>
  
  <p>What I'm noticing is that if the file exits in S3 already , the .upload_file() from boto3 still transfers the file. I did this check by looking at iftop. </p>
  
  <p>Is there some arg i'm missing to disable "auto overwrite if file exists"?</p>
  
  <p>Thanks</p>
  
  <p><strong>edit</strong> trying the head method</p>
  
  <pre><code>s3 = boto3.resource('s3')
  file_name = 'somelogfile.gz'
  
  try:
      s3.Object(s3_bucket+ s3_folder+s3_filename).load()
      print 'success'
  except botocore.exceptions.ClientError as e:
      print e
  </code></pre>