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Golang Arrow Flight Client Application Example

This lightweight Golang client app connects to the Dremio Arrow Flight server endpoint. It requires a username and password for authentication. Developers can use admin or regular user credentials for authentication. Any datasets in Dremio that are accessible by the provided Dremio user can be queried. By default, the hostname is localhost and the port is 32010. Developers can change these default settings by providing the hostname and port as arguments when running the client. Moreover, the tls option can be provided to establish an encrypted connection.

Note: If the tls option is enabled and trusted certs are not provided, the app will attempt to use the host's default root CA bundle.

Instructions on using this Golang Sample application

  • Install and setup Golang in your preferred way
  • Build the app
    • go build
    • go will automatically download the dependencies
  • Alternatively, you can just run the application directly
    • go run .
    • go will still automatically download the dependencies
$ go run . -h
Dremio Client Example.

Usage:
  example -h | --help
  example [--host=<hostname>] [--port=<port>] (--user=<username> --pass=<password> | --pat=<pat>)
          [--tls] [--certs=<path>] [--query <query>] [--project_id=<project_id>]
          [--trace_id=<trace_id>] [--trace_sampled]

Options:
  -h --help           Show this help.
  --host=<hostname>   Dremio coordinator hostname [default: localhost]
  --port=<port>       Dremio flight server port [default: 32010]
  --user=<username>   Dremio username
  --pass=<password>   Dremio password
  --pat=<pat>         Dremio personal access token
  --query <query>     SQL Query to test.
  --tls               Enable encrypted connection.
  --certs=<path>      Path to trusted certificates for encrypted connection.
  --project_id=<project_id>   Dremio project ID
  --trace_id=<trace_id>       W3C trace ID, exactly 32 lowercase hex characters.
  --trace_sampled             Set W3C trace flags to sampled (-01). Defaults to unsampled (-00).

Example

If you have a local instance of Dremio running on localhost:32010 with a user dremio and password dremio123, you can run the following command to connect and do a simple query:

go run . --user=dremio --pass=dremio123 --query="SELECT * FROM (VALUES(1,2,3))"

To connect to a Dremio Cloud instance with data organized in different folders, you must use TLS and generate a Personal Access Token (PAT) for authentication. If your data resides in a specific project, you can specify the project by providing its project_id. If the project_id is not provided, the connection will use the default project.

You can run a command similar to the following::

go run . --host=<cloud.hostname> --port=443 --query="SELECT * FROM \"Samples\".\"samples.dremio.com\".\"NYC-taxi-trips\"" --tls --pat=<mypat> --project_id=<myprojectid>

Here we're querying for a dataset called NYC-taxi-trips, in a source called Samples, in the samples.dremio.com folder.

To send a W3C traceparent header with the Flight calls, provide a 32-character lowercase hex trace ID. The example generates a span ID and sends a header in the form 00-<trace_id>-<span_id>-<trace_flags>. Use --trace_sampled when you need the trace flags byte to be sampled (01):

go run . --host=<cloud.hostname> --port=443 --query="SELECT 1" --tls --pat=<mypat> --trace_id=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa --trace_sampled

Tests

To run the tests, you'll need a flight client mock class. This class is generated using mockgen. To aid in this process, we created a script that generates the mock class and runs all tests. You can run the script using the following command:

./run_tests.sh

If the mock class is already generated you can alternatively use the following command:

go test -v