Bridge PostgreSQL Connectivity with Apache NiFi

Apache NiFi supports powerful and scalable directed graphs of data routing, transformation, and system mediation logic. When paired with the CData JDBC Driver for PostgreSQL, NiFi can work with live PostgreSQL data. This article describes how to connect to and query PostgreSQL data from an Apache NiFi Flow.

With built-in optimized data processing, the CData JDBC driver offers unmatched performance for interacting with live PostgreSQL data. When you issue complex SQL queries to PostgreSQL, the driver pushes supported SQL operations, like filters and aggregations, directly to PostgreSQL and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze PostgreSQL data using native data types.

Connecting to PostgreSQL Data in Apache NiFi

1. Download the CData JDBC Driver for PostgreSQL installer, unzip the package, run the .exe file to install the driver.

2. Copy the CData JDBC Driver JAR file (and license file if it exists), cdata.jdbc.postgresql.jar (and cdata.jdbc.postgresql.lic), to the Apache NiFi lib subfolder, for example, C:\nifi-1.3.0-bin\nifi-1.3.0\lib.

   On Windows, the default location for the CData JDBC Driver is C:\Program Files\CData\CData JDBC Driver for PostgreSQL.

3. Start Apache NiFi by running the run-nifi.bat file in bin subfolder, for example, C:\nifi-1.3.0-bin\nifi-1.3.0\bin.

   (OR)

   Use the command prompt to navigate to the particular directory and run the run-nifi.bat file for example:

   cd C:\nifi-1.3.0-bin\nifi-1.3.0\bin
   .\run-nifi.bat
   

4. Navigate to the Apache NiFi UI in your web browser: It should be https://localhost:8443/nifi.

   Note: If users are utilizing an older version of Apache NiFi, they should access it via http://localhost:8080/nifi. In earlier versions, HTTP was the protocol employed. However, in the most recent version, HTTPS is the standard. By default, HTTP operates on port 8080, while HTTPS uses port 8443.

5. When accessing Apache NiFi via a URL, it prompts you to enter a username and password for login.

   👁 Enter Username and Password for login
   

   To retrieve login credentials, users should consult the 'App.log' file located within the log directory of their NiFi installation. This file typically contains the necessary details for accessing the NiFi interface.

   👁 Retrieve login credentials from App.log file
   
6. Right-click on the Nifi Flow's workspace and click "Controller Services" 👁 Configuring the Process Group
   
7. Click the button to create a new controller service. 👁 Creating a new Controller Service
   
8. In the Controller Services section, location the newly created "DBCPConnection Pool" and click the menu () >> Edit to configure the new connection. 👁 Configure the new DBCPConnection Pool
   

9. Fill in the properties:

   • Database Connection URL: jdbc:postgresql:User=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432;
   • Database Driver Class Name: cdata.jdbc.postgresql.PostgreSQLDriver
   • Database Driver Location(s): Path to your Apache NiFi's lib folder where the JAR files are present.

   Built-in Connection String Designer

   For assistance in constructing the JDBC URL, use the connection string designer built into the PostgreSQL JDBC Driver. Either double-click the JAR file or execute the JAR file from the command-line.

   java -jar cdata.jdbc.postgresql.jar
   

   Fill in the connection properties and copy the connection string to the clipboard.

   To connect to PostgreSQL, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the data provider connects to the user's default database.

   SSH Connectivity for PostgreSQL

   You can use SSH (Secure Shell) to authenticate with PostgreSQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

   SSH Connections to PostgreSQL in Password Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Password"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHPassword: SSH Password

   SSH Connections to PostgreSQL in Public Key Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Public_Key"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHClientCret: the path for the public key certificate file
   👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
   
10. In the Controller Services section, locate the newly created DBCPConnection Pool and click the menu () >> Enable to enable the new connection.
11. In the "Enable Controller Service" window, set Scope to "Service and referencing components" 👁 Setting the scope of the Controller Service
    
12. To establish a connection and execute a select query, simply drag and drop the processor (indicated by the yellow highlight) into the workspace. 👁 Establish a connection and execute a select query
    
13. Select the 'ExecuteSQL' processor and click the 'Add' button to make it visible in the workspace. 👁 Select 'ExecuteSQL' and 'Add'
    
14. Double-click on the added processor (ExecuteSQL)to open the connection page. 👁 Click on ExecuteSQL processor to get redirected to the connection page
    
15. In the Properties section, fill in the required information. Make sure to set the Database Connection Pooling Service to match the DBCPConnectionPool that you have created, and set your desired SQL query that you want to get executed in the SQL select query section. 👁 Verify and test connection
    
16. Go to Relationships and make sure to select an option on how the component should proceed in case of success and failure of the execution process. 👁 Apply the connection
    
17. You can enable the ExecuteSQL component by either selecting it and clicking Enable on the Operation section, or by right-clicking it and selecting Enable. 👁 Click on the lightning button
    

Your PostgreSQL data is now available for use in Apache NiFi. For example, you can use the DBCPConnection Pool as the source for a QueryDatabaseTable processor (shown below).

Download a free, 30-day trial of the CData JDBC Driver for PostgreSQL and start working with your live PostgreSQL data in Apache NiFi. Reach out to our Support Team if you have any questions.