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More about adding a collaboratorConcurrency
The backend provides mutual exclusion when accessing shared data.
- Background
-
- Given
- client accepts JSON
- Scenarios
-
- Bob can acquire the lock to avoid concurrent write accesses
- When Bob has the lock, others can still read
- When he has the lock, Bob can release it
- John must not be able to release Bob's lock
- Only the owner of the object (Bob) or the owner of the lock (John) can see who has the lock
- John and Tom are able to increment safely a shared counter at the same time
- Bob can acquire the lock to avoid concurrent write accesses
-
- Given
-
the system only knows those Buildings:
_id label level _owner _tags 541816f042e7d8204d000001 Town Hall 3 [email protected] [{ "_targets": ["public"], "_permissions": [{"_read":true},{"_write":true}] }] - And
- client is authenticated as Bob
- When
- client requests POST /api/buildings/541816f042e7d8204d000001/lock with JSON: {}
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": "[email protected]" } - When
- client is authenticated as John
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "label": "John's Town Hall", "level": 999 } - Then
- response status should be 422
- When
- client is authenticated as Tom
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "label": "Tom's Town Hall", "level": 999 } - Then
- response status should be 422
- When
- client is authenticated as Bob
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": "[email protected]" } - When
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "label": "Town Hall is mine! Bob.", "level": 999, "_lock": false } - Then
- response status should be 200
- And
-
response body should be JSON:
{ "status": "ok" }
- When Bob has the lock, others can still read
-
- Given
-
the system only knows those Buildings:
_id label level _owner _tags _lock 541816f042e7d8204d000001 Town Hall 3 [email protected] [{ "_targets": ["public"], "_permissions": [{"_read":true},{"_write":true}] }] [email protected] - When
- client is authenticated as John
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": true } - When
- client is authenticated as Tom
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": true }
- When he has the lock, Bob can release it
-
- Given
-
the system only knows those Buildings:
_id label level _owner _tags _lock 541816f042e7d8204d000001 Town Hall 3 [email protected] [{ "_targets": ["[email protected]"], "_permissions": [{"_read":true},{"_write":true}] }] [email protected] - When
- client is authenticated as John
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "label": "John's Town Hall... ?", "level": 999 } - Then
- response status should be 422
- When
- client is authenticated as Bob
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "_lock": false } - Then
- response status should be 200
- And
-
response body should be JSON:
{ "status": "ok" } - When
- client is authenticated as John
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "label": "John's Town Hall... Finally!", "level": 999 } - Then
- response status should be 200
- And
-
response body should be JSON:
{ "status": "ok" }
- John must not be able to release Bob's lock
-
- Given
-
the system only knows those Buildings:
_id label level _owner _tags _lock 541816f042e7d8204d000001 Town Hall 3 [email protected] [{ "_targets": ["[email protected]"], "_permissions": [{"_read":true},{"_write":true}] }] [email protected] - When
- client is authenticated as John
- And
-
client requests PATCH /api/buildings/541816f042e7d8204d000001 with JSON:
{ "_lock": false } - Then
- response status should be 422
- Only the owner of the object (Bob) or the owner of the lock (John) can see who has the lock
-
- Given
-
the system only knows those Buildings:
_id label level _owner _tags _lock 541816f042e7d8204d000001 Town Hall 3 [email protected] [{ "_targets": ["public"], "_permissions": [{"_read":true},{"_write":true}] }] [email protected] - When
- client is authenticated as Bob
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": "[email protected]" } - When
- client is authenticated as John
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": "[email protected]" } - When
- client is authenticated as Tom
- And
- client requests GET /api/buildings/541816f042e7d8204d000001
- Then
- response status should be 200
- And
-
response body should be JSON:
{ "_id": "541816f042e7d8204d000001", "label": "Town Hall", "level": 3, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true}, {"_write":true}]}], "_lock": true }
-
- Given
-
the system only knows those Counters:
_id count _owner _tags 541816f042e7d8204d000001 0 [email protected] [{ "_targets": ["public"], "_permissions": [{"_read":true},{"_write":true}] }] - When
- John and Tom increment the counter with id "541816f042e7d8204d000001" by 25 times each at the same time
- Then
-
Counter with id "541816f042e7d8204d000001" should be JSON:
{ "_id": { "$oid": "541816f042e7d8204d000001" }, "count": 50, "_owner": "[email protected]", "_tags": [{ "_targets": ["public"], "_permissions": [{"_read":true},{"_write":true}] }], "_lock": false }
Last published about 6 years ago by Bruno Le Hyaric.