feature(csdk): proxy agent support example

[fivetran-sinchanahegde]

Jira ticket

Closes https://fivetran.atlassian.net/browse/RD-1202613

Description of Change

Example to use proxy agent in csdk

Testing

• Simple Postgres Connection Connector Example

• Multiple Hosts Connector Example

• custom host key

Checklist

Some tips and links to help validate your PR:

• Tested the connector with fivetran debug command.
• Added/Updated example-specific README.md file, see the README template for the required structure and guidelines.
• Followed Python Coding Standards, refer here

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[Copilot]

Pull request overview

This PR adds a new “Proxy Agent” set of Connector SDK examples showing how to connect to PostgreSQL sources when traffic is routed through a Fivetran Proxy Agent, including single-host, multi-host failover, and a custom proxy host configuration key.

Changes:

• Added three new proxy-agent PostgreSQL connector examples (single host, multiple hosts failover, custom host key).
• Added per-example READMEs, configuration.json templates, and psycopg2-binary dependency pins.
• Updated the top-level examples/README.md to include the new Proxy Agent examples section.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
examples/README.md	Adds links to the new Proxy Agent examples.
examples/common_patterns_for_connectors/proxy_agent/simple_postgres_connection/requirements.txt	Pins psycopg2-binary for the single-host example.
examples/common_patterns_for_connectors/proxy_agent/simple_postgres_connection/README.md	Documents setup, deploy, and behavior for the single-host proxy-agent example.
examples/common_patterns_for_connectors/proxy_agent/simple_postgres_connection/connector.py	Implements the single-host PostgreSQL connector example behind a proxy agent.
examples/common_patterns_for_connectors/proxy_agent/simple_postgres_connection/configuration.json	Provides a placeholder configuration template for the single-host example.
examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/requirements.txt	Pins psycopg2-binary for the multi-host failover example.
examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/README.md	Documents setup and failover behavior for the multi-host example.
examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/connector.py	Implements host iteration + connection failover for proxy-agent PostgreSQL connectivity.
examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/configuration.json	Provides a placeholder configuration template using a hosts array.
examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/requirements.txt	Pins psycopg2-binary for the custom-key example.
examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/README.md	Documents using --proxy-host-config-key and a custom proxy host configuration key.
examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/connector.py	Implements the custom-key variant of proxy-agent PostgreSQL connectivity.
examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/configuration.json	Provides a placeholder configuration template for the custom-key example.

Suppressed comments (4)

examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/connector.py:175

• The update() docstring should match the template connector (URL + exact wording/format) for consistency with the rest of the repo.

    """
    Define the update function, which is a required function, and is called by Fivetran during each sync.
    See the technical reference documentation for more details on the update function
    https://fivetran.com/docs/connectors/connector-sdk/technical-reference#update
    Args:

examples/common_patterns_for_connectors/proxy_agent/custom_proxy_host_key/connector.py:201

• The connector creation + local __main__ debug block should match the repo’s template connector so users get consistent guidance (especially around fivetran debug).

# This creates the connector object that will use the update and schema functions defined in this connector.py file.
connector = Connector(update=update, schema=schema)

# Check if the script is being run as the main module. This is Python's standard entry method allowing your script to
# be run directly from the command line or IDE 'run' button. This is useful for debugging while you write your code.
# Note this method is not called by Fivetran when executing your connector in production. Please test using the
# Fivetran debug command prior to finalizing and deploying your connector.
if __name__ == "__main__":
    try:
        with open("configuration.json", "r") as f:
            configuration = json.load(f)
    except FileNotFoundError:
        configuration = {}
    connector.debug(configuration=configuration)

examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/connector.py:216

• The update() docstring should match the template connector (URL + exact wording/format) so the example stays aligned with the documented API reference.

    """
    Define the update function, which is a required function, and is called by Fivetran during each sync.
    See the technical reference documentation for more details on the update function
    https://fivetran.com/docs/connectors/connector-sdk/technical-reference#update
    Args:

examples/common_patterns_for_connectors/proxy_agent/multiple_hosts/connector.py:242

• The connector creation + local __main__ debug block should match the repo’s template connector so users get consistent guidance (especially around fivetran debug).

# This creates the connector object that will use the update and schema functions defined in this connector.py file.
connector = Connector(update=update, schema=schema)

# Check if the script is being run as the main module. This is Python's standard entry method allowing your script to
# be run directly from the command line or IDE 'run' button. This is useful for debugging while you write your code.
# Note this method is not called by Fivetran when executing your connector in production. Please test using the
# Fivetran debug command prior to finalizing and deploying your connector.
if __name__ == "__main__":
    try:
        with open("configuration.json", "r") as f:
            configuration = json.load(f)
    except FileNotFoundError:
        configuration = {}
    connector.debug(configuration=configuration)

[fivetran-sahilkhirwal]

Looks good

[fivetran-JenasVimal]

NIT comments , will approve one you resolve them

[fivetran-dejantucakov]

@fivetran-sinchanahegde Left a couple of more suggestions/comments

[fivetran-dejantucakov]

@fivetran-sinchanahegde LGTM

[fivetran-JenasVimal]

LGTM

[fivetran-dejantucakov]

@fivetran-sinchanahegde Re-approved