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| − | == Mistral DSL specification == | + | == This Wiki is no longer maintained == |
| − | Version 0.1
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| − | === Main objects ===
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| | | | |
| − | | + | Please see the [https://docs.openstack.org/mistral/latest/user/wf_lang_v2.html Mistral Workflow language documentation]. |
| − | * '''Namespace'''
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| − | * '''Action'''
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| − | * '''Workflow'''
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| − | * '''Task'''
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| − | * '''Trigger'''
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| − | | |
| − | === Namespaces ===
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| − | | |
| − | Provides some specific functionality. For example, Nova service provides functionality for VMs management in OpenStack.
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| − | | |
| − | ==== Attributes ====
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| − | | |
| − | All attributes are inside main keys of '''Namespaces''' - '''namespaces names'''
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| − | * '''class''' - currently we support the following classes: std.http, std.mistral_http, std.echo, std.email, std.ssh, this is an optional attribute
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| − | * '''base-parameters''' - dictionary depending on type of the namespace, this parameter can be optional. Values of this parameters apply to all actions inside namespace. For example for std.http it can contain url, method, body and headers.
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| − | * '''actions''' - list of actions provided by this namespace
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| − | | |
| − | ==== YAML example: ====
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| − | | |
| − | Namespaces:
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| − | Nova:
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| − | class: std.http
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| − | parameters:
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| − | method: GET
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| − | actions:
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| − | create-vm:
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| − | ......
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| − | delete-vm:
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| − | .....
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| − | | |
| − | === Action ===
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| − | | |
| − | A function provided by services. For example Nova service provides the following actions: create-vm, shutdown-vm
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| − | | |
| − | ==== Attributes ====
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| − | | |
| − | * '''name''' - string without space, mandatory attribute
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| − | * '''parameters''' - dictionary, which structured is defined by service type. For REST service it contains url and method.
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| − | * '''task-parameters''' - dictionary containing parameters which should or could be specified in task
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| − | * '''response''' - dictionary containing keys ''''select'''' and ''''store_as''''. Value for ''''select'''' - YAQL expression and means what data action should extract as its result. Value for ''''store_as'''' - string key which should be used for storing in the execution context
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| − | | |
| − | ==== YAML example: ====
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| − | | |
| − | create-vm:
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| − | parameters:
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| − | url: servers
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| − | task-parameters:
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| − | name:
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| − | optional: False
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| − | response:
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| − | select: '$.server.id'
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| − | store_as: vm_id
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| − | | |
| − | === Workflow ===
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| − | | |
| − | ==== Attributes ====
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| − | | |
| − | * '''tasks''' - list of task in this workflow, each task represent some step in worflow
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| − | * '''events''' - list of events in workflow, e.g. timer or periodic events
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| − | | |
| − | ==== YAML example: ====
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| − | | |
| − | Workflow:
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| − | tasks:
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| − | create-vms:
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| − | .....
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| − | attache-volumes:
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| − | .....
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| − | | |
| − | === Task ===
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| − | | |
| − | Represents a step in workflow, for example attaching volume
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| − | | |
| − | ==== Attributes ====
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| − | | |
| − | * '''name''' - string without space, mandatory attribute
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| − | * '''action''' - name of action to perform
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| − | * '''requires''' - list of tasks which should be execute before this tasks, or list of task names as a keys and condition as a value, this is optional parameter
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| − | * '''parameters''' - list of parameters
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| − | * '''on-success''' - task which will be scheduled on execution after current task has finished with state 'SUCCESS'
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| − | * '''on-error''' - task which will be scheduled on execution after current task has finished with state 'ERROR'
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| − | * '''on-finish''' - task which will be scheduled on execution after current task has finished
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| − | | |
| − | YAML example:
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| − | | |
| − | create-vms:
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| − | action: Nova:create-vm
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| − | parameters:
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| − | image_id: 1234
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| − | flavor_id: 42
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| − | requires:
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| − | task2: '$.value2 = 123'
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| − | task4: '$.value4 = 122'
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| − | on-success: task3
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| − | | |
| − | === Events ===
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| − | | |
| − | By event it is possible to invoke specific task.
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| − | | |
| − | ==== Attributes ====
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| − | | |
| − | * '''name''' - string without space, mandatory attribute
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| − | * '''type''' - can be PERIODIC, TIMER, CEILOMETER_ALARM
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| − | * '''tasks''' - list of tasks which should be execute on event
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| − | * '''parameters''' - list of parameters, defined by task
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| − | | |
| − | ==== YAML example: ====
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| − | | |
| − | backup-vm:
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| − | type: periodic
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| − | tasks: [create_backup, delete_old_backup]
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| − | parameters:
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| − | time: 1 0 * * *
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| − | | |
| − | === Full YAML example: ===
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| − | | |
| − | Workflow:
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| − | tasks:
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| − | runJob:
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| − | requires:
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| − | createVM: $.vm_ip != null
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| − | action: DemoApp:runJob
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| − | on-success: deleteVM
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| − | on-error: sendJobError
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| − |
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| − | deleteVM:
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| − | action: Nova:deleteVM
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| − | on-finish: end
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| − |
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| − | sendJobError:
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| − | action: std:email
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| − | parameters:
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| − | address: admin@mycompany.com
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| − | subject: Workflow error
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| − | body: Error occurred while running a VM job in execution {$.execution.id}
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| − | on-finish: deleteVM
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| − |
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| − | # Creating a VM and waiting till it is up (an IP address has been assigned).
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| − |
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| − | createVM:
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| − | action: Nova:createVM
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| − | on-success: waitForIP
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| − | on-error: sendCreateVMError
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| − |
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| − | waitForIP:
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| − | action: std:repeat
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| − | parameters:
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| − | task: getIP
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| − | retries: 5
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| − | delay: 3000
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| − | break-on: $.vm_ip != null
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| − | on-finish:
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| − | sendCreateVMError: $.vm_ip = null
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| − | on-error:
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| − | sendCreateVMError
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| − |
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| − | getIP:
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| − | action: Nova:getIP
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| − |
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| − | sendCreateVMError:
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| − | action: std:email
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| − | parameters:
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| − | address: admin@mycompany.com
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| − | subject: Workflow error
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| − | body: Failed to create a VM in execution {$.execution.id}
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| − | on-finish: end
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| − |
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| − | # Terminal no-op task.
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| − |
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| − | end:
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| − | action: Util:no-op
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| − |
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| − | events:
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| − | runJob:
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| − | type: periodic
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| − | tasks: runJob
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| − | parameters:
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| − | cron-pattern: "*/1 * * * *"
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| − |
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| − | Services:
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| − | Nova:
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| − | type: REST_API
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| − | parameters:
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| − | baseUrl: {$.novaURL}
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| − | actions:
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| − | createVM:
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| − | parameters:
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| − | url: /servers/{$.vm_id}
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| − | method: POST
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| − | response:
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| − | select: $.server.id
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| − | store-as: vm_id
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| − | getIP:
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| − | parameters:
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| − | url: /servers/{$.vm_id}
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| − | method: GET
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| − | response:
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| − | select: $.server.accessIPv4
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| − | store-as: vm_ip
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| − | deleteVM:
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| − | parameters:
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| − | url: /servers/{$.vm_id}
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| − | method: DELETE
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| − |
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| − | DemoAPP:
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| − | type: MISTRAL_REST_API
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| − | parameters:
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| − | baseUrl: http://{$.vm_ip}:8080/
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| − | actions:
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| − | runJob:
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| − | parameters:
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| − | url: /runJob
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| − | method: GET
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| − | | |
| − | ==== Initial execution context ====
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| − | {
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| − | "novaURL": TBD,
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| − | "imageID": TBD
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| − | }
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| − | | |
| − | '''When a workflow starts Mistral also adds execution information into the context so the context looks like the following:'''
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| − | | |
| − | {
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| − | "novaURL": TBD,
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| − | "imageID": TBD,
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| − | "execution": {
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| − | "id": "234234",
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| − | "workbook_name" : "my_workbook",
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| − | "project_id": "ghfgsdfasdfasdf"
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| − | "auth_token": "sdfljsdfsdf-234234234",
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| − | "trust_id": "oiretoilkjsdfglkjsdfglkjsdfg"
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| − | }
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| − | }
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