The querier service handles request for entry querying. It exposes an HTTP
interface which accepts the sql and user information which it then uses to
generate and execute a query against the extracted processing data.

The SQL query is rewritten so that it is able to be executed in the application
database (converts columns into json selectors for the `data` column, converts
book in `from` clause into a filter and uses correct table) and add filters to
the query for the appropriate user and book.


=== Requirements

- See requirements for web application


=== Development

    go generate ./...   # execute code generators
    go build            # build the service
    go run .            # run the service locally
    go test ./...       # run all tests


=== Configuration

The services needs to know what database to connect to and port binding
information for the HTTP service. This is done using the following environment
variables:

    QUERIER_DB_CONN     # database connection url, example "postgres://ro_user@localhost:5432/captainslog"
    QUERIER_HTTP_LISTEN # http host/port string, example ":8082"


=== Container

    # Build image with querier binary. Make sure to run this in this
    # directory (<captainslogroot>/querier)
    docker build -t minond/captainslog-querier -f Dockerfile .

    # Run it using local configuration and binding to the correct host and
    # container port Make sure you have a .env file with the required environment
    # variables in the directory where you run this command.
    docker run -d --env-file .env --name cl-querier -p 8082:8082 minond/captainslog-querier

    # Push to container repo.
    docker push minond/captainslog-querier:latest