Add possibility to export environment variables with .env file

[RobertLucian]

Description

Add support for exporting environment variables from an .env file placed in the root directory of a Cortex project.

Motivation

In case the user doesn't want to export environment variables using the predictor:env field in cortex.yaml. A reason for that could be to keep the cortex.yaml deployment clean.

[lminer]

Does this expose the environment variables to the tensorflow-serving image as well? I'm trying to read directly from s3 from tensorflow-serving and it isn't seeing my credentials.

[RobertLucian]

@lminer only the predictor.image container gets the exported variables from .env. So the answer is no, they don't get exported for the predictor.tensorflow_serving_image container.

predictor.tensorflow_serving_image at least in our view is only for TFS - anything else is done in the API container (predictor.image). Is it possible for you to start a service or anything that you want in dependencies.sh instead? dependencies.sh includes the exported environment variables and it runs before the API, inside the API container. Here's more on dependencies.sh.

Also, your API will inherit the cluster's AWS credentials (provided it's an AWS cluster, read this for more) and so you don't have to export them again - unless these credentials are for S3 buckets that fall outside the API credentials' scope. Can you tell us more about this use case?

I see that you want to read from an S3 bucket. If it's a model you want to download, Cortex already handles that awesomely. More on that here. Is this what you want? If not, can you tell us about your case?

[lminer]

@RobertLucian because of the GRPC limit on the amount of data that I can send to tensorflow-serving, I thought that instead I would simply send a link to an object in an s3 bucket and then read and write to s3 directly within the model itself. However, in order to do this, I need some way to get the AWS credentials to the model and it appears as if this can only be done via environment variables.

[RobertLucian]

@lminer I see. That would not be an optimal architecture.

We have increased the priority on #1740 and it's the next thing for me to work on. Since this seems to be urgent to you, we will probably make a patch release for you or just create a customised image that will work for you. Will this be acceptable to you?

[lminer]

That would be great. Thank you!

[deliahu]

@lminer I'd just like to add that the AWS credential environment variables are populated in the TF serving container. In addition, you can add custom env vars in both the predictor container and the TF serving container by specifying env in your API configuration, e.g.

- name: iris-classifier
  kind: RealtimeAPI
  predictor:
    type: tensorflow
    path: predictor.py
    models:
      path: s3://cortex-examples/tensorflow/iris-classifier/nn/
    env:
      MY_VAR: my-value

That said, I agree with @RobertLucian that the best approach will be to address #1740.

[lminer]

Ah. Does this hold if you use a .env file too? I tried it with that and tensorflow wasn't seeing my aws creds.

[RobertLucian]

@lminer it doesn't hold for the .env file though. It's only for the env vars specified in the API spec.

[lminer]

@deliahu Are you sure that the env vars from the yaml file are propagated to the tensorflow-serving image? I'm still getting the error of aws creds not being properly set. Moreover, when I attach to the tensorflow-serving docker container and run printenv I don't see the environment variables.

Here's my cortex.yaml

- name: pasta
  kind: RealtimeAPI
  predictor:
    type: tensorflow
    path: serving/cortex_server.py
    models:
      path: ../pasta_bucket/
      signature_key: serving_default
    image: quay.io/cortexlabs/tensorflow-predictor:0.25.0
    tensorflow_serving_image: quay.io/robertlucian/cortex-tensorflow-serving-gpu-tf2.4:0.25.0
    env:
      AWS_ACCESS_KEY_ID: foo
      AWS_SECRET_ACCESS_KEY: bar 

Here's the error:

2021-01-07 17:22:25.306428: W external/org_tensorflow/tensorflow/core/framework/op_kernel.cc:1763] OP_REQUIRES failed at whole_file_read_ops.cc:116 : Failed precondition: AWS Credentials have not been set properly. Unable to access the specified S3 location
<_InactiveRpcError of RPC that terminated with:
        status = StatusCode.FAILED_PRECONDITION
        details = "2 root error(s) found.
  (0) Failed precondition: AWS Credentials have not been set properly. Unable to access the specified S3 location
         [[{{node ReadFile}}]]
         [[StatefulPartitionedCall/StatefulPartitionedCall/StatefulPartitionedCall/while/body/_1860/while/StatefulPartitionedCall/StatefulPartitionedCall/up_sample_layer_2/batch_normalization_177/FusedBatchNormV3/truediv/_3347]]
  (1) Failed precondition: AWS Credentials have not been set properly. Unable to access the specified S3 location
         [[{{node ReadFile}}]]
0 successful operations.
0 derived errors ignored."
        debug_error_string = "{"created":"@1610040145.309085820","description":"Error received from peer ipv4:172.17.0.2:9000","file":"src/core/lib/surface/call.cc","file_line":1061,"grpc_message":"2 root error(s) found.\n  (0) Failed precondition: AWS Credentials have not been set properly. Unable to access the specified S3 location\n\t [[{{node ReadFile}}]]\n\t [[StatefulPartitionedCall/StatefulPartitionedCall/StatefulPartitionedCall/while/body/_1860/while/StatefulPartitionedCall/StatefulPartitionedCall/up_sample_layer_2/batch_normalization_177/FusedBatchNormV3/truediv/_3347]]\n  (1) Failed precondition: AWS Credentials have not been set properly. Unable to access the specified S3 location\n\t [[{{node ReadFile}}]]\n0 successful operations.\n0 derived errors ignored.","grpc_status":9}"