Linux DSN Configuration

This section shows how to connect to Google BigQuery and execute SQL queries from several Linux distributions: Debian-based systems, like Ubuntu, and Red Hat Linux platforms, like Red Hat Enterprise Linux (RHEL), CentOS, and Fedora.

Using a Driver Manager

Before installing the CData ODBC Driver for Google BigQuery 2016 on Linux, you will need to install a driver manager. ODBC-compliant applications connect to the driver through a driver manager. After you connect, the driver manager loads the driver and passes function calls from the application to the driver. The driver manager also implements some functions for discovering the registered drivers and DSNs. DSNs can be defined for a specific user or system wide.

Installing unixODBC

Precompiled binaries for the unixODBC driver manager are available for many operating systems.

On Debian-based systems like Ubuntu, you can install unixODBC by running the following command as root or with sudo:

apt-get install unixODBC unixODBC-dev

On Red Hat Enterprise Linux, CentOS, and Fedora, you can install unixODBC with YUM or DNF. For example, run the following command as root or with sudo:

yum install unixODBC unixODBC-devel

If binaries are not available for your operating system, you will need to compile unixODBC yourself. Please refer to the unixODBC website for more information about obtaining binaries or compiling unixODBC on your operating system.

Installing the Driver Dependencies

Minimum Linux Versions

Below are the minimum supported versions for Red Hat-based and Debian-based systems:


OS	Min. Version
Ubuntu	11
Debian	7
RHEL	6
CentOS	6
Fedora	13

Required Libraries and Packages

Below are the libraries required by the driver and their corresponding packages:


Debian/Ubuntu Package	RHEL/CentOS/Fedora Package	File
libc6	glibc	linux-vdso.1
libc6	glibc	libm.so.6
libc6	glibc	librt.so.1
libc6	glibc	libdl.so.2
libc6	glibc	libpthread.so.0
libc6	glibc	libc.so.6
libc6	glibc	ld-linux-x86-64.so.2
libstdc++6	libstdc++	libstdc++.so.6
zlib1g	zlib	libz.so.1
libgcc1	libgcc	libgcc_s.so.1

Installing the Packages

You can install the necessary dependencies with the following commands:

Debian/Ubuntu:

apt-get install libc6 libstdc++6 zlib1g libgcc1

RHEL/CentOS/Fedora:
```
yum install glibc libstdc++ zlib libgcc
```

Setting Up OAuth

OAuth requires the authenticating user to interact with Google BigQuery, using the browser. The driver facilitates this in various ways as described in the following sections; to complete the authentication guide, first check if your environment needs additional configuration.

If the first OAuth interaction is to be done on the same machine the driver is installed on -- for example, a desktop application -- the driver will need access to the xdg-open program, which opens the default browser.

This OAuth flow is not possible on some systems, such as headless machines, servers, and machines disconnected from the Internet. You can use stored procedures to authenticate without this dependency.


Debian/Ubuntu Package	RHEL/CentOS/Fedora Package	File
xdg-utils	xdg-utils	xdg-open

Installing the Driver

You can use standard package management systems to easily and quickly install the driver.

On Debian-based systems, like Ubuntu, you can install the driver by running the following command as root or with sudo:

dpkg -i /path/to/.deb

On systems that support the RPM package format, you can install the driver by running the following command as root or with sudo:

rpm -Uvh /path/to/.rpm

Using the unixODBC Configuration Files

You can determine the location of the configuration files on your system by entering the following command into a terminal:

odbcinst -j

Below is an example of the output of this command:

DRIVERS............: /etc/odbcinst.ini
SYSTEM DATA SOURCES: /etc/odbc.ini
FILE DATA SOURCES..: /etc/ODBCDataSources
USER DATA SOURCES..: /home/myuser/.odbc.ini
SQLULEN Size.......: 8
SQLLEN Size........: 8
SQLSETPOSIROW Size.: 8

The driver installation registers the driver for system-wide use and creates a system DSN with empty values for commonly required properties. Modifying unixODBC's system-wide settings requires elevated permissions; to do so, you can use root or the sudo command.

Configuring a DSN

ODBC data sources are defined in sections in the odbc.ini file.

In addition to the connection properties required to connect to your data source, the Driver property specifies either a driver definition in the odbcinst.ini file or the path to the driver library.

[CData GoogleBigQuery Source]
Driver = CData ODBC Driver for GoogleBigQuery
Description = My Description
MyConnectionProperty1 = My Value
MyConnectionProperty2 = My Value2

You can list the data sources on your system with the following command:

odbcinst  -q -s

Authenticating to Google

Google BigQuery uses the OAuth authentication standard. You can authorize the driver to access Google APIs on behalf on individual users or on behalf of users in a domain.

See Using OAuth for a guide.

Connecting to Google BigQuery

In addition to the OAuth values, specify the DatasetId and ProjectId. You can fine-tune the Google BigQuery functionality surfaced by the driver with the Advanced Settings.

Authenticating Web Applications

On headless servers or other machines on which the driver is not authorized to open a browser, the driver cannot obtain the access token automatically. However, it can still automatically refresh the token. To obtain the token, you can call the driver's stored procedures, GetOAuthAuthorizationURL and GetOAuthAccessToken. First, set the InitiateOAuth inside the Other property to one of the following:

OFF: Indicates that the OAuth flow will be handled entirely by the user. An OAuthAccessToken will be required to authenticate.
REFRESH: Indicates that the driver will only handle refreshing the OAuthAccessToken. The user will never be prompted by the driver to authenticate via the browser. The user must handle obtaining the OAuthAccessToken and OAuthRefreshToken initially. The OAuth values are persisted in the OAuthSettingsLocation Other property.

After calling GetOAuthAccessToken, set the following in the Other property as well:

OAuthAccessToken
OAuthRefreshToken

Refreshing OAuth Values

The driver can not only initiate the OAuth exchange, but also refresh the tokens when they expire. To enable the automatic token exchange, you can give the driver write access to /etc/odbc.ini or set the OAuthSettingsLocation property, an Other property, to persist the encrypted tokens to an alternate file path that the driver has write access to.

Configuring Driver Definitions

The sections of the odbcinst.ini file map a driver name to the driver library. The section begins with the driver name; the Driver property points to the path to the driver library. The driver library is the .so file located by default in /opt/cdata/googlebigquery/lib. A Description property can also be provided.

You can list the drivers installed on the system with the following command:

odbcinst -q -d

Testing the Connection

You can use isql, included with unixODBC, to execute SQL queries to Google BigQuery from the command line. When testing the connection, use the -v flag to output any messages from the driver manager and the driver.

isql -v "CData GoogleBigQuery Source"