[AMBARI-22649] Library for querying cluster_settings and stack_settings in command*.json.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: ambari-server
• Labels: pull-request-available
• Epic Link: Config Management in Multi Everything Architecture
• Assignee: Swapan Shridhar
• Reporter: Swapan Shridhar
• Created: 14/Dec/17 01:58
• Updated: 10/Mar/18 08:27
• Resolved: 19/Dec/17 14:18

Description

Background : AMBARI-22198 added "stack settings", and AMBARI-22196 introduced "cluster settings" in Ambari.

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Library for querying clusterSettings and stackSettings for its contents in command*.json.
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One should be able to query for a given clusterSettings or stackSettings:

• by passing in the setting name(one or more) in order to get it back as key-value map, or
• just get the value back for a passed-in setting.

Functions for clusterSettings:
-----------------------------------------

• get_cluster_setting_entries(setting_names) :
  • Retrieves the passed-in cluster setting entr(y/ies) and their values as a map.
    If 'setting_names' is passed-in as None : all the settings names and their corresponding values will be returned as map.
    If 'setting_names' is passed-in as empty set : None will be returned.

• get_cluster_setting_value(setting_name) :
  • Retrieves the passed-in cluster setting entry's value.

• is_security_enabled() :
  • Retrieves the cluster's security status.

Functions for stackSettings:
-----------------------------------------

Stack settings as of now has 5 settings : stack_name, stack_root, stack_features, stack_tools, stack_packages. stack_name, stack_root have string as values, whereas stack_features, stack_tools, stack_packages have values as JSON. Further there already exists python functions in files : stack_features.py, stack_tools.py and stack_select.py.

• get_stack_setting_entries(setting_names) :
  • Retrieves the passed-in stack setting entr(y/ies) and their values as a map.
    If 'setting_names' is passed-in as None, all the settings names and their corresponding values will be returned as map.
    If 'setting_names' is passed-in as empty set : None will be returned.

• get_stack_setting_value(setting_name):
  • Retrieves the passed-in stack setting entry's value.

• get_stack_name():
  • Retrieves the stack name.

• get_stack_root():
  • Retrieves the stack root.

Modifications in stack_features.py, stack_tools.py and stack_select.py files:
--------------------------------------------------------------------------------------------------------------

• Given that these already exist and as of now they read the relevant stack setting from configurations/cluster_env.
• Thus, code has been added to try reading from /stackSettings first by calling the new fn.() get_stack_setting_value(). if setting not found, go for the fall back configurations/cluster_env (which would be removed soon, when we remove cluster_env).

Issue Links

• links to: GitHub Pull Request #419
• links to: GitHub Pull Request #536
• links to: Reviewboard