Extension

You can add additional logic using Gohan Extension. Extensions has properties:

id identity of the code
code contents of a code
code_type javascript and goext are supported
URL placement of code. Currently, file://, http:// and https:// schemes are supported
path resource path to execute code

Example Code

  extensions:
  - code: console.log(Object.keys(context));
    id: test
    path: /v2.0/.*

Gohan supports two types of extensions:

javascript
golang (as a plugin, loadable at runtime)

Comparison of different types of extensions:

Name	type-id	language	execution performance	loadable at runtime
javascript	javascript	javascript	interpreted	yes
golang (plugin)	goext	golang	native	yes

Event

pre_list

list event before DB operation

context.response contains response data. You can also update response here

Note you can skip DB operation if you set context response in here

pre_list_in_transaction

Same as pre_list but executed in the DB transaction context.transaction contains transaction object for DB operation

id : request id

context.response contains response data. You can also update response here

post_list_in_transaction

Same as post_list but executed in the DB transaction context.transaction contains transaction object for DB operation

id : request id context.response contains response data. You can also update response here

post_list

list event after DB operation.

context.response contains response data. You can also update response here

pre_show

show event before DB access

id : request id context.response contains response data. You can also update response here

Note you can skip DB operation if you set context response in here

pre_show_in_transaction

Same as pre_show but executed in the DB transaction context.transaction contains transaction object for DB operation

id : request id context.response contains response data. You can also update response here

post_show_in_transaction

Same as post_show but executed in the DB transaction context.transaction contains transaction object for DB operation

id : request id context.response contains response data. You can also update response here

post_show

show event after DB operation

id : request id context.response contains response data. You can also update response here

pre_create

executed before creation Mainly used for validation purpose

context.resource contains user input data

Note you can skip DB operation if you set context response in here

pre_create_in_transaction

Same as pre_create but executed in the DB transaction context.transaction contains transaction object for DB operation

post_create_in_transaction

after creation in the transaction

post_create

after create context.response contains response data. context.transaction contains transaction object for db operation

pre_update

executed before an update Mainly used for validation purpose

context.resource contains user input data

Note you can skip DB operation if you set context response in here

pre_update_in_transaction

same as pre_update but executed in the db transaction context.transaction contains transaction object for db operation

post_update_in_transaction

after creation in transaction

post_update

after update context.response contains response data. context.transaction contains transaction object for db operation

pre_delete

executed before delete Mainly used for validation purpose

context.id contains resource id we are trying to delete context.transaction contains transaction object for db operation

pre_delete_in_transaction

same as pre_delete but executed in the db transaction context.transaction contains transaction object for db operation

post_delete_in_transaction

after creation in transaction

post_delete

after delete

pre_state_update_in_transaction

executed before a state update triggered by a backend event

context.resource contains the resource associated with the update, context.state contains the state changes, context.config_version contains the current config version

post_state_update_in_transaction

as above, but after the state update

pre_monitoring_update_in_transaction

executed before a monitoring update triggered by a backend event

context.resource contains the resource associated with the update, context.monitoring contains the new monitoring information

post_monitoring_update_in_transaction

as above, but after the monitoring update

notification

executed when you receive a cron notification

Context

Each handler receives 'context' object which is associated with http request. Context type is a map with string keys.
Each context contains following items:

path - string - URL Path
http_request - *http.Request - object representing API call
http_response - map[string]interface{} - object representing API response
request_data - map[string]interface{} - API request body
schema - schema.Schema - schema defining given path
schema_id - string - schema ID
tenant_id - string - tenant ID (empty when scoped to domain)
domain_id - string - domain ID
params - map[string]interface{} - HTTP request parameters
sync - sync.Sync - Sync client
DB - db.DB - DB client
identity_service - middleware.IdentityService - identity service
service_auth - schema.Authorization - Autorization object
openstack_client - *gophercloud.ServiceClient - OpenStack client