Linux DSN Configuration

This section describes how to set up ODBC connectivity and configure DSNs on several Linux distributions: Debian-based systems, like Ubuntu, and Red Hat Linux platforms, like Red Hat Enterprise Linux (RHEL), CentOS, and Fedora.

Minimum Linux Versions

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


OS	Min. Version
Ubuntu	11.04
Debian	7
RHEL	6.9
CentOS	6.9
Fedora	13
SUSE	12.1

Installing the Driver Dependencies

Run the following commands as root or with sudo to install the necessary dependencies:

Debian/Ubuntu:

apt-get install libc6 libstdc++6 zlib1g libgcc1

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

Here are the corresponding libraries required by the driver:


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 Driver

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

On Debian-based systems, like Ubuntu, run the following command with root or sudo:

dpkg -i /path/to/driver/setup/GoogleDataCatalogODBCDriverforUnix.deb

On systems that support the RPM package format, run the following command with root or sudo:

rpm -ivh /path/to/driver/GoogleDataCatalogODBCDriverforUnix.rpm

Licensing the Driver

Run the following commands to license the driver. To activate a trial, omit the <key> input.

cd /opt/cdata/cdata-odbc-driver-for-googledatacatalog/bin/
sudo ./install-license.sh <key>

Connecting through the Driver Manager

The driver manager loads the driver and passes function calls from the application to the driver. You need to register the driver with the driver manager and you define DSNs in the driver manager's configuration files.

The driver installation registers the driver with the unixODBC driver manager and creates a system DSN. The unixODBC driver manager can be used from Python and from many other applications. Your application may embed another driver manager.

Creating the DSN

See Using unixODBC to install unixODBC and configure DSNs. See Using the DataDirect Driver Manager to create a DSN to connect to OBIEE, Informatica, and SAS.

Connecting to Google Data Catalog

Provide the following connection properties before adding the authentication properties.

OrganizationId: The ID associated with the Google Cloud Platform organization resource you would like to connect to. Find this by navigating to the cloud console.
Open the Project drop-down menu and click the link to your organization from the list. The organization ID is displayed on this page.
ProjectId: The ID associated with the Google Cloud Platform project resource you would like to connect to.
Find this by navigating to the cloud console dashboard and selecting your project from the Select from drop-down menu. The project ID is displayed in the Project info card.

Authenticating to Google Data Catalog

The driver supports using user accounts, service accounts and GCP instance accounts for authentication.

The following sections discuss the available authentication schemes for Google Data Catalog:

User Accounts (OAuth)
Service Account (OAuthJWT)
GCP Instance Account

User Accounts (OAuth)

AuthScheme must be set to OAuth in all user account flows.

Desktop Applications

CData provides an embedded OAuth application that simplifies OAuth desktop Authentication. Alternatively, you can create a custom OAuth application. See Creating a Custom OAuth App for information about creating custom applications and reasons for doing so.

For authentication, the only difference between the two methods is that you must set two additional connection properties when using custom OAuth applications.

After setting the following connection properties, you are ready to connect:

InitiateOAuth: Set this to GETANDREFRESH, which instructs the driver to automatically attempt to get and refresh the OAuth access token.
OAuthClientId: (custom applications only) Set this to the Client Id in your custom OAuth application settings.
OAuthClientSecret: (custom applications only) Set this to the Client Secret in the custom OAuth application settings.

When you connect the driver opens the OAuth endpoint in your default browser. Log in and grant permissions to the application. The driver then completes the OAuth process as follows:

Extracts the access token from the callback URL.
Obtains a new access token when the old one expires.
Saves OAuth values in OAuthSettingsLocation that persist across connections.

Headless Machines

To configure the driver to use OAuth with a user account on a headless machine, you need to authenticate on another device that has an internet browser.

Choose one of two options:
- Option 1: Obtain the OAuthVerifier value as described in "Obtain and Exchange a Verifier Code" below.
- Option 2: Install the driver on a machine with an Internet browser and transfer the OAuth authentication values after you authenticate through the usual browser-based flow, as described in "Transfer OAuth Settings" below.
Then configure the driver to automatically refresh the access token on the headless machine.

Option 1: Obtain and Exchange a Verifier Code

To obtain a verifier code, you must authenticate at the OAuth authorization URL.

Follow the steps below to authenticate from the machine with an Internet browser and obtain the OAuthVerifier connection property.

Choose one of these options:
- If you are using the Embedded OAuth Application click Google Data Catalog OAuth endpoint to open the endpoint in your browser.
- If you are using a custom OAuth application, create the Authorization URL by setting the following properties:
  - InitiateOAuth: Set to OFF.
  - OAuthClientId: Set to the client Id assigned when you registered your application.
  - OAuthClientSecret: Set to the client secret assigned when you registered your application.
  Then call the GetOAuthAuthorizationURL stored procedure with the appropriate CallbackURL. Open the URL returned by the stored procedure in a browser.
Log in and grant permissions to the driver. You are then redirected to the callback URL, which contains the verifier code.
Save the value of the verifier code. Later you will set this in the OAuthVerifier connection property.

Next, you need to exchange the OAuth verifier code for OAuth refresh and access tokens. Set the following properties:

On the headless machine, set the following connection properties to obtain the OAuth authentication values:

InitiateOAuth: Set this to REFRESH.
OAuthVerifier: Set this to the verifier code.
OAuthClientId: (custom applications only) Set this to the Client Id in your custom OAuth application settings.
OAuthClientSecret: (custom applications only) Set this to the Client Secret in the custom OAuth application settings.
OAuthSettingsLocation: Set this to persist the encrypted OAuth authentication values to the specified file.

After the OAuth settings file is generated, you need to re-set the following properties to connect:

InitiateOAuth: Set this to REFRESH.
OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
OAuthSettingsLocation: Set this to the file containing the encrypted OAuth authentication values. Make sure this file gives read and write permissions to the driver to enable the automatic refreshing of the access token.

Option 2: Transfer OAuth Settings

Prior to connecting on a headless machine, you need to create and install a connection with the driver on a device that supports an Internet browser. Set the connection properties as described in "Desktop Applications" above.

After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the path specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Once you have successfully tested the connection, copy the OAuth settings file to your headless machine.

On the headless machine, set the following connection properties to connect to data:

InitiateOAuth: Set this to REFRESH.
OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
OAuthSettingsLocation: Set this to the path to your OAuth settings file. Make sure this file gives read and write permissions to the driver to enable the automatic refreshing of the access token.

Service Accounts (OAuthJWT)

To authenticate using a service account, you must create a new service account and have a copy of the accounts certificate. If you do not already have a service account, you can create one by following the procedure in Creating a Custom OAuth App.

For a JSON file, set these properties:

AuthScheme: Set this to OAuthJWT.
InitiateOAuth: Set this to GETANDREFRESH.
OAuthJWTCertType: Set this to GOOGLEJSON.
OAuthJWTCert: Set this to the path to the .json file provided by Google.
OAuthJWTSubject: (optional) Only set this value if the service account is part of a GSuite domain and you want to enable delegation. The value of this property should be the email address of the user whose data you want to access.

For a PFX file, set these properties instead:

AuthScheme: Set this to OAuthJWT.
InitiateOAuth: Set this to GETANDREFRESH.
OAuthJWTCertType: Set this to PFXFILE.
OAuthJWTCert: Set this to the path to the .pfx file provided by Google.
OAuthJWTCertPassword: (optional) Set this to the .pfx file password. In most cases you must provide this since Google encrypts PFX certificates.
OAuthJWTCertSubject: (optional) Set this only if you are using a OAuthJWTCertType, which stores multiple certificates. This should not be set for PFX certificates generated by Google.
OAuthJWTIssuer: Set this to the email address of the service account. This address usually includes the domain iam.gserviceaccount.com.
OAuthJWTSubject: (optional) Only set this value if the service account is part of a GSuite domain and you want to enable delegation. The value of this property is the email address of the user whose data you want to access.

GCP Instance Accounts

When running on a GCP virtual machine, the driver can authenticate using a service account tied to the virtual machine. To use this mode, set AuthScheme to GCPInstanceAccount.

Refreshing OAuth Values

The driver can refresh the temporary OAuth access tokens obtained during the browser-based OAuth authentication exchange. By default, the driver saves the encrypted tokens in the odbc.ini file corresponding to the DSN. Access to this odbc.ini file can be restricted in the case of System DSNs.

To enable the automatic token exchange, you can give the driver write access to the system odbc.ini.

Installing Dependencies for OAuth Authentication

The OAuth authentication standard requires the authenticating user to interact with Google Data Catalog, using a web-browser. 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 needs access to the xdg-open program, which opens the default browser.

To satisfy this dependency, install the corresponding package with your package manager:


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

Set the Driver Encoding

The ODBC drivers need to specify which encoding to use with the ODBC Driver Manager. By default, the CData ODBC Drivers for Unix are configured to use UTF-16 which is compatible with unixODBC, but other Driver Managers may require alternative encoding.

Alternatively, if you are using the ODBC driver from an application that uses the ANSI ODBC API it may be necessary to set the ANSI code page. For example, to import Japanese characters in an ANSI application, you can specify the code page in the config file '/opt/cdata/cdata-odbc-driver-for-googledatacatalog/lib/cdata.odbc.googledatacatalog.ini':

[Driver]
AnsiCodePage = 932

ODBC Driver for Google Data Catalog