Write a Simple Go Application to work with HCL Domino Data on Linux

Use CData ODBC drivers and unixODBC to create a simple Go app with live connectivity to HCL Domino data.

Go is an open source programming language that enables you to easily build software on Linux/UNIX machines. When Go is paired with the ODBC Driver for HCL Domino and unixODBC you are able write applications with connectivity to live HCL Domino data. This article will walk you through the process of installing the ODBC Driver for HCL Domino, configuring a connection using the unixODBC Driver Manager, and creating a simple Go application to work with HCL Domino data.

Using the CData ODBC Drivers on a Unix/Linux Machine

The CData ODBC Drivers are supported in various Red Hat-based and Debian-based systems, including Ubuntu, Debian, RHEL, CentOS, and Fedora. There are also several libraries and packages that are required, many of which may be installed by default, depending on your system. For more information on the supported versions of Linux operating systems and the required libraries, please refer to the "Getting Started" section in help documentation (installed and found online).

Installing the Driver Manager

Before installing the driver, you need to be sure that your system has a driver manager. For this article, you will use unixODBC, a free and open source ODBC driver manager that is widely supported.

For Debian-based systems like Ubuntu, you can install unixODBC with the APT package manager:


apt-get install unixodbc unixodbc-dev

For systems based on Red Hat Linux, you can install unixODBC with yum or dnf:


yum install unixODBC unixODBC-devel

The unixODBC driver manager reads information about drivers from an odbcinst.ini file and about data sources from an odbc.ini file. You can determine the location of the configuration files on your system by entering the following command into a terminal:


odbcinst -j

NOTE: You may need to install odbcinst. Use the following command in a terminal:


apt install odbcinst

The output of the command will display the locations of the configuration files for ODBC data sources and registered ODBC drivers. User data sources can only be accessed by the user account whose home folder the odbc.ini is located in. System data sources can be accessed by all users. 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

Installing the Driver

You can download the driver in standard package formats: the Debian .deb package format or the .rpm file format. Once you have downloaded the file, you can install the driver from the terminal.

The driver installer registers the driver with unixODBC and creates a system DSN, which can be used later in any tools or applications that support ODBC connectivity.

For Debian-based systems like Ubuntu, run the following command with sudo or as root: dpkg -i /path/to/package.deb

For systems that support .rpms, run the following command with sudo or as root: rpm -i /path/to/package.rpm

Once the driver is installed, you can list the registered drivers and defined data sources using the unixODBC driver manager:

List the Registered Driver(s)


odbcinst -q -d
CData ODBC Driver for HCL Domino
...

List the Defined Data Source(s)


odbcinst -q -s
CData Domino Source
...

To use the CData ODBC Driver for HCL Domino with unixODBC, you need to ensure that the driver is configured to use UTF-16. To do so, edit the INI file for the driver (cdata.odbc.domino.ini), which can be found in the lib folder in the installation location (typically /opt/cdata/cdata-odbc-driver-for-domino), as follows:

cdata.odbc.domino.ini


...

[Driver]
DriverManagerEncoding = UTF-16

Modifying the DSN

When the driver is installed, a system DSN should be predefined. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties. Additionally, you can create user-specific DSNs that will not require root access to modify in $HOME/.odbc.ini.

Connecting to Domino

To connect to Domino data, set the following properties:

URL: The host name or IP of the server hosting the Domino database. Include the port of the server hosting the Domino database. For example: http://sampleserver:1234/
DatabaseScope: The name of a scope in the Domino Web UI. The driver exposes forms and views for the schema governed by the specified scope. In the Domino Admin UI, select the Scopes menu in the sidebar. Set this property to the name of an existing scope.

Authenticating with Domino

Domino supports authenticating via login credentials or an Azure Active Directory OAuth application:

Login Credentials

To authenticate with login credentials, set the following properties:

AuthScheme: Set this to "OAuthPassword"
User: The username of the authenticating Domino user
Password: The password associated with the authenticating Domino user

The driver uses the login credentials to automatically perform an OAuth token exchange.

AzureAD

This authentication method uses Azure Active Directory as an IdP to obtain a JWT token. You need to create a custom OAuth application in Azure Active Directory and configure it as an IdP. To do so, follow the instructions in the Help documentation. Then set the following properties:

AuthScheme: Set this to "AzureAD"
InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
OAuthClientId: The Client ID obtained when setting up the custom OAuth application.
OAuthClientSecret: The Client secret obtained when setting up the custom OAuth application.
CallbackURL: The redirect URI defined when you registered your app. For example: https://localhost:33333
AzureTenant: The Microsoft Online tenant being used to access data. Supply either a value in the form companyname.microsoft.com or the tenant ID.

The tenant ID is the same as the directory ID shown in the Azure Portal's Azure Active Directory > Properties page.

/etc/odbc.ini or $HOME/.odbc.ini


[CData Domino Source]
Driver = /opt/cdata/cdata-odbc-driver-for-domino/lib/libdominoodbc.x64.so
Description = My Description
Server = https://domino.corp.com
AuthScheme = OAuthPassword
User = my_domino_user
Password = my_domino_password

For specific information on using these configuration files, please refer to the help documentation (installed and found online).

Creating a Simple Go App for HCL Domino Data

With the Driver Manager installed and the DSN configured, you are ready to create a simple Go application to work with your HCL Domino data. To start, install a Go driver for ODBC databases. While there are several options available, this article will use the odbc driver found at https://github.com/alexbrainman/odbc.

Installing ODBC on Linux

There are a series of steps required to install the ODBC driver for Go.

Create the $HOME/golang/go path (if it does not exist) by entering the following commands in a terminal: mkdir /root/golang mkdir /root/golang/go
Define the GOPATH environment variable: export GOPATH=$HOME/golang/go
Create a module inside the new Go directory: cd $GOPATH go mod init myproject
Install the Go driver for ODBC databases:
go get http://github.com/alexbrainman/odbc

Now you are ready to create and execute a simple Go application.

Sample Go Application

The sample application issues a simple SQL SELECT query for HCL Domino data and displays the results. Create the directory $GOPATH/src/cdata-odbc-domino and create a new Go source file, copying the source code from below.

cdata-odbc-domino.go


package main

import (
  _ "github.com/alexbrainman/odbc"
  "database/sql"
  "log"
  "fmt"
)

func main() {
  db, err := sql.Open("odbc",
    "DSN=CData Domino Source")
  if err != nil {
    log.Fatal(err)
  }

  var (
    name string
    address string
  )

  rows, err := db.Query("SELECT Name, Address FROM ByName WHERE City = ?", "Miami")
  if err != nil {
    log.Fatal(err)
  }
  defer rows.Close()
  for rows.Next() {
    err := rows.Scan(&name, &address)
    if err != nil {
      log.Fatal(err)
    }
    fmt.Println(name, address)
  }
  err = rows.Err()
  if err != nil {
    log.Fatal(err)
  }

  defer db.Close()
}

In the terminal, navigate to the Go application directory and build the application:


go build

After the application builds, you will be able to execute the application, displaying your HCL Domino data:


./cdata-odbc-domino

At this point, you have a simple Go application for working with HCL Domino data. From here, you can easily expand the application, adding deeper read functionality through familiar SQL queries.

Ready to get started?

Download a free trial of the HCL Domino ODBC Driver to get started:

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HCL Domino ODBC Driver

The HCL Domino ODBC Driver is a powerful tool that allows you to connect with live data from HCL Domino, directly from any applications that support ODBC connectivity.

Access HCL Domino data like you would a database - read, write, and update HCL Domino FALSE, etc. through a standard ODBC Driver interface.

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