title: Cannot read .json from a google cloud bucket
body: <p>I have a folder structure within a bucket of google cloud storage</p>
  
  <pre><code>bucket_name = 'logs'
  json_location = '/logs/files/2018/file.json'
  </code></pre>
  
  <p>I try to read this <code>json</code> file in <code>jupyter notebook</code> using this code </p>
  
  <pre><code>from google.cloud import storage 
  
  os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = "logs/files/2018/file.json"
  
  def download_blob(source_blob_name, bucket_name, destination_file_name): 
      """Downloads a blob from the bucket.""" 
      storage_client = storage.Client() 
      bucket = storage_client.get_bucket(bucket_name) 
      blob = bucket.blob(source_blob_name) 
  
      blob.download_to_filename(destination_file_name) 
  
      print('Blob {} downloaded to {}.'.format(
          source_blob_name, 
          destination_file_name)) 
  </code></pre>
  
  <p>Then calling the function</p>
  
  <pre><code>download_blob('file.json', 'logs', 'file.json')
  </code></pre>
  
  <p>And I get this error</p>
  
  <pre><code>DefaultCredentialsError: File /logs/files/2018/file.json was not found.
  </code></pre>
  
  <p>I have looked at all the similar question asked on stackoverflow and cannot find a solution. </p>
  
  <p>The <code>json</code> file is present and can be open or downloaded in the json_location on google cloud storage.</p>