ods-exd-api-box 1.2.0

Helper package to build ASAM ODS EXD API grpc plugins.

ASAM ODS EXD-API for NI TDMS Files

ASAM ODS EXD-API Architecture

sequenceDiagram

actor CLIENT as Client
participant PDTT as 🛠️Importer
participant PODS as 🗃️ASAM ODS server
participant PLUGIN as 📊EXD-API plugin
participant FILE as 🗂️File Storage

autonumber

opt Import phase
  FILE ->>+ PDTT: New file shows up
  PDTT ->>+ PLUGIN : Get Structure
  PLUGIN -> FILE: Extract content information
  PLUGIN ->> PLUGIN: Create Structure
  PLUGIN ->>- PDTT: Return Structure
  PDTT ->> PODS: Import ODS structure
  Note right of PDTT: Create hierarchy<br/>AoTest,AoMeasurement,...
  PDTT ->>- PODS: Add External Data info
  Note right of PDTT: Attach AoFile ... for external data<br/>AoFile,AoSubmatrix,AoLocalColumn,...
end

Note over CLIENT, FILE: Now we can work with the imported files

loop Runtime phase
  CLIENT ->> PODS: Establish ODS session
  CLIENT ->> PODS: Work with meta data imported from structure
  CLIENT ->> PODS: Access external channel in preview
  PODS ->> PLUGIN: GetValues
  PLUGIN ->> FILE: Get Channel values
  PLUGIN ->> PODS: Return values of channels
  PODS ->> CLIENT: Return values needed for plot
end

Configuration & Usage

Server Options

python external_data_file.py --help

Key configuration options:

Option	Default	Description
--port	50051	gRPC server port
--bind-address	[::]	Server bind address
--max-workers	CPU count × 2	Thread pool size
--max-concurrent-streams	None	Max concurrent gRPC streams
--use-tls	False	Enable TLS/SSL
--tls-cert-file	-	Path to server certificate (PEM)
--tls-key-file	-	Path to server private key (PEM)
--tls-client-ca-file	-	CA bundle for client verification
--require-client-cert	False	Require valid client certificate
--verbose	False	Enable debug logging
--health-check-enabled	False	Enable health check service

TLS Configuration

Basic TLS:

python external_data_file.py \
  --use-tls \
  --tls-cert-file /path/to/server.crt \
  --tls-key-file /path/to/server.key

Mutual TLS (mTLS):

python external_data_file.py \
  --use-tls \
  --tls-cert-file /path/to/server.crt \
  --tls-key-file /path/to/server.key \
  --tls-client-ca-file /path/to/client-ca.crt \
  --require-client-cert

Docker with TLS:

docker run \
  -v /path/to/certs:/certs \
  -p 50051:50051 \
  ghcr.io/totonga/asam-ods-exd-api-nptdms:latest \
  --use-tls \
  --tls-cert-file /certs/server.crt \
  --tls-key-file /certs/server.key

Development

Setup Development Environment

# Install with development dependencies
pip install -e ".[dev]"

Type Checking

mypy .

Running Tests

python -m unittest discover -s tests

Running Docker Integration Tests

python -m unittest tests.test_docker_integration -v

Code Style

The project uses:

• Black for code formatting
• isort for import sorting
• Pylint for linting
• Mypy for static type checking

Updating Protocol Buffers

The protobuf files are generated from the ASAM ODS standard specifications:

# Download latest proto files
curl -o ods.proto https://raw.githubusercontent.com/asam-ev/ASAM-ODS-Interfaces/main/ods.proto
curl -o ods_external_data.proto https://raw.githubusercontent.com/asam-ev/ASAM-ODS-Interfaces/main/ods_external_data.proto

# Generate Python stubs
mkdir -p ods_exd_api_box/proto
python3 -m grpc_tools.protoc \
  -I. \
  --python_out=ods_exd_api_box/proto/. \
  --pyi_out=ods_exd_api_box/proto/. \
  --grpc_python_out=ods_exd_api_box/proto/. \
  ods.proto ods_external_data.proto

Performance Considerations

• File Caching - Opened files are cached to minimize I/O operations
• Reference Counting - Automatic resource cleanup with reference counting
• Thread Pool - Configurable worker threads for parallel request handling
• Message Size Limits - Configurable max send/receive message sizes

Troubleshooting

Connection Refused

Ensure the server is running and listening on the correct port:

netstat -tlnp | grep 50051

TLS Certificate Errors

Verify certificate paths and permissions:

openssl x509 -in /path/to/cert.crt -text -noout

Type Checking Failures

Ensure all dependencies are installed with type stubs:

pip install -e ".[dev]"
mypy .

Contributing

Contributions are welcome! Please:

0. Use dev container or set up local dev environment
1. Ensure type checking passes: `mypy .
2. Run tests: python -m unittest discover -s tests
3. Follow code style (Black, isort)
4. Add tests for new features

License

MIT License - see LICENSE file for details.

References

• ASAM ODS Standard
• ASAM ODS GitHub Repository
• gRPC Documentation
• Peak-Solution Data Management Learning Path