剧本中的 Ansible 变量检查

Question

I have in the vars file the databases configured as the following:

project_dbs:
  - { project_db_name: "project1", project_db_user: "user", tenon_db_password: "pass" }
  - { project_db_name: "project2",  project_db_user: "dev", tenon_db_password: "pass2"}
  - { project_db_name: "project3", project_db_user: "{{datadog_mysql_username}}", project_db_password: "{{datadog_mysql_password}}" }

Now in a playbook I have a check:

 - name: copy config.json template to server
   tags: provision
   template: src=config.json dest={{ project_root }}/config
   when: item.project_db_name == "project2"
   with_items: project_dbs

But the when check is failing. Any idea how to make that work?

The error message looks like this:

fatal: [test]: FAILED! => {"failed": true, "msg": "The conditional check 'item.projects_db_name == \\"project2\\"' failed. The error was: error while evaluating conditional (item.projects_db_name == \\"project2\\"): 'unicode object' has no attribute 'projects_db_name'\\n\\nThe error appears to have been in '/var/lib/jenkins/project/ansible/roles/project2/tasks/main.yml': line 28, column 3, but may\\nbe elsewhere in the file depending on the exact syntax problem.\\n\\nThe offending line appears to be:\\n\\n\\n- name: copy config.json template to server\\n ^ here\\n"}

Answer 1

You use an outdated syntax called "bare variables" in with_items :

with_items: project_dbs

This way your item becomes a string object with the value of project_dbs and Ansible reports it doesn't have the attribute ("'unicode object' has no attribute 'projects_db_name'").

In Ansible 2.x you should quote variables in the following way:

with_items: "{{ project_dbs }}"

---

That said, your task makes no use of the values from the loop. The following will have the same effect:

- name: copy config.json template to server
  tags: provision
  template: src=config.json dest={{ project_root }}/config

Answer 2

Instead of using when you could just filter the list of project_dbs so it looks like this:

- name: "copy config.json template to server"
  tags: provision
  template: src=config.json dest={{ project_root }}/config
  with_items: "{{ project_dbs | selectattr("project_db_name", "project2") }}"