awx/docs/prompting.md

Launch-time Configurations / Prompting

Admins of templates in AWX have the option to allow fields to be over-written by user-provided values at the time of launch. The job that runs will then use the launch-time values in lieu of the template values.

Fields that can be prompted for, and corresponding "ask_" variables (which exist on the template and must be set to true to enable prompting) are the following.

Standard Pattern with Character Fields

• ask_<variable>_on_launch allows use of
  • <variable>

The standard pattern applies to fields

• job_type
• skip_tags
• limit
• diff_mode
• verbosity

Non-Standard Cases (Credentials Changing in Tower 3.3)

• ask_variables_on_launch allows unrestricted use of
  • extra_vars
• ask_tags_on_launch allows use of
  • job_tags
• Enabled survey allows restricted use of
  • extra_vars, only for variables in survey (with qualifiers)
• ask_credential_on_launch allows use of
  • credential
  • vault_credential / extra_credentials / credentials (version-dependent, see notes below)
• ask_inventory_on_launch allows use of
  • inventory

Surveys are a special-case of prompting for variables - applying a survey to a template white-lists variable names in the survey spec (requires the survey spec to exist and survey_enabled to be true). On the other hand, if ask_variables_on_launch is true, users can provide any variables in extra_vars.

(supported, but deprecated) Prompting enablement for several types of credentials is controlled by a single field. On launch, multiple types of credentials can be provided in their respective fields inside of credential, vault_credential, and extra_credentials. Providing credentials that require password input from the user on launch is allowed, and the password must be provided along-side the credential, of course.

If the job is being spawned using a saved launch configuration, all credential types are managed by a many-to-many relationship called credentials relative to the launch configuration object. The credentials in this relationship will either add to the job template's credential list, or replace a credential in the job template's list if it is the same type.

Manual use of Prompts

Fields enabled as prompts in the template can be used for the following actions in the API.

• POST to /api/v2/job_templates/N/launch/
  • can accept all prompt-able fields
• POST to /api/v2/workflow_job_templates/N/launch/
  • can accept extra_vars and inventory
• POST to /api/v2/system_job_templates/N/launch/
  • can accept certain fields, with no user configuration

When launching manually, certain restrictions apply to the use of credentials

• if providing any of credential, vault_credential, and extra_credentials this becomes the "legacy" method, and imposes additional restrictions on relaunch, and is mutually exclusive with the use of credentials field
• if providing credentials, existing credentials on the job template may only be removed if replaced by another credential of the same type this is so that relaunch will use the up-to-date credential on the template if it has been edited since the prior launch

Data Rules for Prompts

For the POST action to launch, data for "prompts" are provided as top-level keys in the request data. There is a special-case to allow a list to be provided for credentials, which is otherwise not possible in AWX API design. The list of credentials provided in the POST data will become the list for the spawned job.

Values of null are not allowed, if the field is not being over-ridden, the key should not be given in the payload. A 400 should be returned if this is done.

Example:

POST to /api/v2/job_templates/N/launch/ with data:

{
  "job_type": "check",
  "limit": "",
  "credentials": [1, 2, 4, 5],
  "extra_vars": {}
}

where the job template has credentials [2, 3, 5], and the credential type are the following:

• 1 - gce
• 2 - ssh
• 3 - gce
• 4 - aws
• 5 - openstack

Assuming that the job template is configured to prompt for all these, fields, here is what happens in this action:

• job_type of the job takes the value of "check"
• limit of the job takes the value of "", which means that Ansible will target all hosts in the inventory, even though the job template may have been targeted to a smaller subset of hosts
• The job uses the credentials with primary keys 1, 2, 4, and 5
• extra_vars of the job template will be used without any overrides

If extra_vars in the request data contains some keys, these will be combined with the job template extra_vars dictionary, with the request data taking precedence.

Provided credentials will replace any job template credentials of the same exclusive type. In the example, the job template credential 3 was replaced with the provided credential 1, because a job may only use 1 gce credential because these two credentials define the same environment variables and configuration file. If the job had not provided the credential 1, a 400 error would have been returned because the job must contain the same types of credentials as its job template.

Saved Launch-time Configurations

Several other mechanisms which automatically launch jobs can apply prompts at launch-time that are saved in advance.

• Workflow nodes
• Schedules
• Job relaunch / re-scheduling
• (partially) workflow job templates

In the case of workflow nodes and schedules, the prompted fields are saved directly on the model. Those models include Workflow Job Template Nodes, Workflow Job Nodes (a copy of the first), and Schedules.

The many-to-many credentials field differs from other fields because they are managed through a sub-endpoint relative to the node or schedule. This relationship contains the additional credentials to apply when it spawns a job.

Jobs, themselves, have a configuration object stored in a related model, and only used to prepare the correct launch-time configuration for subsequent re-launch and re-scheduling of the job. To see these prompts for a particular job, do a GET to /api/v2/jobs/N/create_schedule/.

Workflow Node Launch Configuration

Workflow job nodes will combine extra_vars from their parent workflow job with the variables that they provide in extra_data, as well as artifacts from prior job runs. Both of these sources of variables have higher precedence than the variables defined in the node.

All prompts that a workflow node passes to a spawned job abides by the rules of the related template. That means that if the node's job template has ask_variables_on_launch set to false with no survey, the workflow node's variables will not take effect in the job that is spawned. If the node's job template has ask_inventory_on_launch set to false and the node provides an inventory, this resource will not be used in the spawned job. If a user creates a node that would do this, a 400 response will be returned.

Workflow Job Template Prompts

Workflow JTs are different than other cases, because they do not have a template directly linked, so their prompts are a form of action-at-a-distance. When the node's prompts are gathered, any prompts from the workflow job will take precedence over the node's value.

As a special exception, extra_vars from a workflow will not obey JT survey and prompting rules, both both historical and ease-of-understanding reasons. This behavior may change in the future.

Other than that exception, JT prompting rules are still adhered to when a job is spawned, although so far this only applies to the workflow job's inventory field.

Job Relaunch and Re-scheduling

Job relaunch does not allow user to provide any prompted fields at the time of relaunch. Relaunching will re-apply all the prompts used at the time of the original launch. This means that:

• all prompts restrictions apply as-if the job was being launched with the current job template (even if it has been modified)
• RBAC rules for prompted resources still apply

Those same rules apply when created a schedule from the /api/v2/schedule_job/ endpoint.

Jobs orphaned by a deleted job template can be relaunched, but only with organization or system administrator privileges.

Credential Password Prompting Restriction

If a job template uses a credential that is configured to prompt for a password at launch, these passwords cannot be saved for later as part of a saved launch-time configuration. This is for security reasons.

Credential passwords can be provided at time of relaunch.

Validation

The general rule for validation:

When a job is created from a template, only fields specifically configured to be prompt-able are allowed to differ from the template to the job.

In other words, if no prompts (including surveys) are configured, a job must be identical to the template it was created from, for all fields that become ansible-playbook options.

Disallowed Fields

If a manual launch provides fields not allowed by the rules of the template, the behavior is:

• Launches without those fields, ignores fields
• lists fields in ignored_fields in POST response

Data Type Validation

All fields provided on launch, or saved in a launch-time configuration for later, should be subject to the same validation that they would be if saving to the job template model. For example, only certain values of job_type are valid.

Surveys impose additional restrictions, and violations of the survey validation rules will prevent launch from proceeding.

Fields Required on Launch

Failing to provide required variables also results in a validation error when manually launching. It will also result in a 400 error if the user fails to provide those fields when saving a WFJT node or schedule.

Broken Saved Configurations

If a job is spawned from schedule or a workflow in a state that has rejected prompts, this should be logged, but the job should still be launched, without those prompts applied.

If the job is spawned from a schedule or workflow in a state that cannot be launched (typical example is a null inventory), then the job should be created in an "error" state with job_explanation containing a summary of what happened.

Scenarios to have Coverage for

• variable precedence
  • schedule has survey answers for WFJT survey
  • WFJT has node that has answers to JT survey
  • on launch, the schedule answers override all others
• survey password durability
  • schedule has survey password answers from WFJT survey
  • WFJT node has answers to different password questions from JT survey
  • Saving with "$encrypted$" value will either
    • become a no-op, removing the key if a valid question default exists
    • replace with the database value if question was previously answered
  • final job it spawns has both answers encrypted
• POST to associate credential to WFJT node
  • requires admin to WFJT and execute to JT
  • this is in addition to the restriction of ask_credential_on_launch
• credentials merge behavior
  • JT has machine & cloud credentials, set to prompt for credential on launch
  • schedule for JT provides no credentials
  • spawned job still uses all JT credentials
• credentials deprecated behavior
  • manual launch providing "extra_credentials": [] should launch with no job credentials
  • such jobs cannot have schedules created from them