How to Add a String into a Dictionary in Ansible with Conditions

Learn how to conditionally add strings to dictionaries in Ansible for efficient management of ping results and message formatting.
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Solving the Problem: Conditional String Addition in Ansible

When automating tasks in IT environments using Ansible, you may face various challenges related to data management and processing. One specific issue you might encounter is the need to add strings into a dictionary based on certain conditions. This is especially common when dealing with the results of tasks, such as ping tests on hosts, where you want to compile a message containing the status of each host for notifications like Slack messages.

The Scenario: Ping Testing Windows Hosts

Imagine you are working on a playbook that performs a ping test on several Windows hosts. Your aim is to compile a concise message indicating which hosts are reachable and which are not. Here's a representation of what your ping task outputs might look like:

[[See Video to Reveal this Text or Code Snippet]]

You would typically want to create two lists: one containing the names of hosts that responded with "pong" (indicating they are reachable) and another list for those that did not (indicating they are unreachable).

Solution Breakdown

Here’s how you can achieve this in Ansible:

1. Understanding the Output Structure

The ping_results variable is specific to each host and won't be directly accessible as a list of results. Instead, it retains the result of the last executed ping for the specified host.

2. Running a Loop on a Central Host

To evaluate the responses of all the hosts, you need to centralize your processing. This is done by using localhost in your Ansible playbook to gather results from all hosts in your group. Here's a sample playbook:

[[See Video to Reveal this Text or Code Snippet]]

3. Breaking it Down by Task

Set Fact for Lists: Start with creating empty lists for ok_list and nok_list. These will be used to store the names of reachable and unreachable hosts, respectively.

Conditionally Add Hosts to ok_list: Use set_fact to add hosts to ok_list based on whether their ping result equals "pong".

Add Hosts to nok_list: Similarly, populate nok_list for hosts that do not return "pong".

4. Result

By running the playbook, you should see a debug output showing two separate lists for both reachable and unreachable hosts:

[[See Video to Reveal this Text or Code Snippet]]

This structured approach allows you to effectively manage ping results and format messages for Slack or other notification systems.

Conclusion

In conclusion, adding strings to dictionaries in Ansible based on conditional checks can streamline your automation workflows. By following the steps outlined, you can successfully gather and categorize host status from ping tests, making it easier to communicate results effectively. This technique can be adapted to various use cases within your automation practices.

For further exploration, dive into advanced Ansible features that allow for more sophisticated data processing and notification mechanisms!