Mercedes Benz IO 2018 Challenge (SINFO) - Winner Solution
Mercedes-Benz IO 2018 challenge given at the SINFO conference.
This is the winner solution of the competition.
I've implemented all of the features, including the two marked as "improvement suggestions".
I ran and tested the application on Linux OS only: 4.14.13-1-ARCH #1 SMP PREEMPT Wed Jan 10 11:14:50 UTC 2018 x86_64 GNU/Linux.
Dependencies
This program has no external dependencies. It's implemented in Python 3
using only the constructs and functions provided by its standard library.
I purposefully avoided using the (new formatted string literals)[https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-pep498] introduced in Python 3.6, so any version of Python 3 should work.
To determine if your local version of Python 3 is supported, simply run the
tests (described below). If they pass without issues, everything should
work fine.
On my machine, I was using
Python 3.6.4 (default, Dec 23 2017, 19:07:07)
[GCC 7.2.1 20171128] on linux
Building/Running The application
usage: python3 run.py [-h] -f FILE [-p PORT]
Mercedes-Benz IO TestDrive application. Developed as part of the MB IO
challenge at SINFO 25.
optional arguments:
-h, --help show this help message and exit
-f FILE, --file FILE Path to the file containing the JSON dataset.
-p PORT, --port PORT Port on which to start the HTTP Server.
For example, run the application using the provided datase, simply execute the following command from the project's root directory:
python3 run.py -f ./tests/resources/dataset_full.json -p 8081
After that, you can start making requests to the endpoints at http://localhost:<port>
Running Tests
To run the application tests, simply execute the following command from the project's root directory:
python3 -m unittest discover tests
Note: the tests at test/test_server.py use the port 1234, so either make sure you have that port free or change it to some other value at the test.test_server.RESTServerTestCase.SERVER_PORT.
Checking Test Coverage
If you want to check the coverage, you can use the coverage.py tool.
You can install it with pip:
pip3 install coverage
After that, you can use the following one-liner to run all of the tests and print the coverage summary:
coverage run -m unittest discover tests; coverage report -m
I recommend you installing coverage.py in a virtual environment.
Additional Comments
I decided to implement the solutions using only what the Python 3 distribution provides out of the box, without using any external dependencies.
I did this not because I don't know how to to use pip or don't know any
libraries that could've helped me, but rather as a result of the motivation that I got from my conversation
with the MB IO representative at SINFO 25.
What he told me was that many of the front-end developers that they
used to have/interviewed only knew the frameworks (AngularJS, ReactJS)
and not the language itself (JavaScript). He told me that they would fail
at the most basic questions about it (like == vs ===).
Even though using external libraries was explicitly allowed for the back-end challenge, I decided to go "raw" and only use what Python comes with.
For the most part, I followed the TDD approach.
Unfortunately, due to lack of time I did not have enough time (master thesis work and other errands) to implement
more tests. The coverage is good: 97%+, but if I had more time I would've added more server tests and improve them. The domain test coverage is 100%.
The distance computation between two coordinates, as well as the coordinate in polygon test does not take Earth's curvature into consideration.
The last run showed the following coverage:
Ran 82 tests in 8.698s
OK
Name Stmts Miss Cover Missing
----------------------------------------------------------------------
mbio/__init__.py 0 0 100%
mbio/date/bookingdate.py 47 0 100%
mbio/date/utils.py 4 0 100%
mbio/exceptions.py 18 0 100%
mbio/geo/__init__.py 0 0 100%
mbio/geo/coordinate.py 59 0 100%
mbio/geo/exceptions.py 2 0 100%
mbio/server/__init__.py 0 0 100%
mbio/server/decorators.py 20 10 50% 19-30
mbio/server/endpoint.py 8 0 100%
mbio/server/server.py 234 36 85% 114, 168-170, 196-197, 212-213, 217-218, 229-232, 249-250, 265-266, 278-282, 293-294, 298-301, 308-309, 327, 332-335, 348
mbio/testdrive.py 158 0 100%
mbio/utils.py 14 0 100%
tests/test_bookings.py 111 0 100%
tests/test_cooridinates.py 63 0 100%
tests/test_date.py 85 0 100%
tests/test_list_dealers_by_distance.py 158 0 100%
tests/test_listing.py 169 0 100%
tests/test_server.py 146 0 100%
tests/test_test_drive.py 10 0 100%
tests/test_utils.py 15 0 100%
----------------------------------------------------------------------
TOTAL 1321 46 97%
REST API
All of the endpoint names are located in the server/enpoint.py file. The server tests are located at tests/test_server.py.
In case I made mistakes in the documentation, please check those two files for relevant information or just contact me.
List Vehicles
Fetch a list of vehicles which match a specific model, fuel, transmission, dealer or any combination of those.
-
URL
/api/vehicles?dealer=:dealer_id&model=:model&fuel=:fuel&transmission=:transmission -
Method:
GET -
URL Params
Optional:
dealer_id=[string]model=[string]fuel=[string]transmission=[string] -
Success Response:
- Code: 200
Content: List of zero or more vehicles.{ "vehicles": [{ "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": ["1000", "1030"], "monday": ["1000", "1030"] } }, { "id": "875f00fa-9f67-44ea-bb26-75ff375fdd3f", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": ["1000", "1030"], "monday": ["1000", "1030"] } }]
- Code: 200
}
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Error message content here" }`
* **Sample Calls:**
curl -X GET
'http://localhost:8081/api/vehicles?model=E&fuel=electric&transmission=auto&dealer=846679bd-5831-4286-969b-056e9c89d74c'
Response:
{ "vehicles": [ { "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } } ] }
curl -X GET
'http://localhost:8081/api/vehicles?model=E&fuel=electric'
curl -X GET
'http://localhost:8081/api/vehicles/'
## Find Closest Dealer With Vehicle
Return the closest dealer closest to a specified location that has a
vehicle with cerntain attributes.
* **URL**
`/api/dealers/closest?latitude=:latitude&longitude=:longitude&model=:model&fuel=:fuel&transmission=:transmission`
* **Method:**
`GET`
* **URL Params**
**Required:**
`latitude=[float]`
`longitude=[float]`
**Optional:**
`model=[string]`
`fuel=[string]`
`transmission=[string]`
* **Success Response:**
* **Code:** 200 <br />
**Content:** single dealer or `null`
```
{
"dealer": {
"id": "bbcdbbad-5d0b-45ef-90ac-3581b997e063",
"name": "MB Lisboa",
"latitude": 38.746721,
"longitude": -9.229837,
"closed": [
"sunday",
"monday"
],
"vehicles": [
{
"id": "778a04fd-0a6a-4dc7-92bb-a7517608efc2",
"model": "A",
"fuel": "ELECTRIC",
"transmission": "AUTO",
"availability": {
"tuesday": [
"1000",
"1030"
],
"wednesday": [
"1000",
"1030"
]
}
},
{
"id": "893d97bf-5a9d-4926-ace3-39ad0585c912",
"model": "AMG",
"fuel": "ELECTRIC",
"transmission": "AUTO",
"availability": {
"tuesday": [
"1000",
"1030"
],
"wednesday": [
"1000",
"1030"
]
}
},
{
"id": "44a36bfa-ec8f-4448-b4c2-809203bdcb9e",
"model": "E",
"fuel": "GASOLINE",
"transmission": "MANUAL",
"availability": {
"tuesday": [
"1000",
"1030"
],
"wednesday": [
"1000",
"1030"
]
}
},
{
"id": "d723b0bd-8eb0-4826-bf5d-44754005d174",
"model": "AMG",
"fuel": "GASOLINE",
"transmission": "AUTO",
"availability": {
"tuesday": [
"1000",
"1030"
],
"wednesday": [
"1000",
"1030"
]
}
}
]
}
}
```
OR
```
{
"dealer": null
}
```
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Message content here" }`
* **Sample Call:**
curl -X GET
'http://localhost:8081/api/dealers/closest?latitude=38.187787&longitude=-8.104157&model=amg&fuel=gasoline&transmission=manual'
Response:
{ "dealer": { "id": "846679bd-5831-4286-969b-056e9c89d74c", "name": "MB Albufeira", "latitude": 37.104404, "longitude": -8.236308, "closed": [ "friday", "wednesday" ], "vehicles": [ { "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "d5d0aabc-c0de-4f38-badc-759f96f5fca3", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "1cd6eae7-5f6f-42a7-a4ca-de7e498d9ce4", "model": "AMG", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } } ] } }
## Get Dealers With Vehicle In A Polygon
Get the dealers within a polygon that have a vehicle with the specified
attributes. The polygon can have any shape, and can be any `n-polygon`,
with `n>=3` (as per its definition).
* **URL**
`/api/dealers/polygon/`
``
Body:
{ "coordinates": [list], "model": [string] "fuel": [string], "transmission": [string] }
Example body:
{ "coordinates": [ [42.203891, -9.525033], [36.800254, -9.349252], [37.203849, -5.899545], [42.268963, -6.031381] ], "model": "E", "fuel": "gasoline", "transmission":"manual" }
Where
"coordinates": [ [42.203891, -9.525033], [36.800254, -9.349252], [37.203849, -5.899545], [42.268963, -6.031381] ]
Are the vertices of the polygon. In this case, the polygon is composed of 4
vertices: [42.203891, -9.525033], [36.800254, -9.349252], [37.203849, -5.899545] and [42.268963, -6.031381]. The format is the following: `[latitude, longitude]`. So `[42.203891, -9.525033]` means that `latitude = 42.203891` and `longitude = -9.525033`.
* **Method:**
`POST`
* **Data Params**
**Required:**
`coordinates=[list]` - list of lists. Each list element is a polygon point.
**Optional:**
`model=[string]`
`fuel=[string]`
`transmission=[string]`
* **Success Response:**
* **Code:** 200 <br />
**Content:** List of dealers wit the specified vehicle inside the polygon or empty list.
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Message content here" }`
* **Sample Calls:**
curl -X POST
http://localhost:8081/api/dealers/polygon/
-d '{
"coordinates": [
[42.203891, -9.525033],
[36.800254, -9.349252],
[37.203849, -5.899545],
[42.268963, -6.031381]
],
"model": "E",
"fuel": "gasoline",
"transmission":"manual"
}'
{ "dealers": [ { "id": "bbcdbbad-5d0b-45ef-90ac-3581b997e063", "name": "MB Lisboa", "latitude": 38.746721, "longitude": -9.229837, "closed": [ "sunday", "monday" ], "vehicles": [ { "id": "778a04fd-0a6a-4dc7-92bb-a7517608efc2", "model": "A", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "893d97bf-5a9d-4926-ace3-39ad0585c912", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "44a36bfa-ec8f-4448-b4c2-809203bdcb9e", "model": "E", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "d723b0bd-8eb0-4826-bf5d-44754005d174", "model": "AMG", "fuel": "GASOLINE", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } } ] } ] }
curl -X POST
http://localhost:8081/api/dealers/polygon/
-d '{
"coordinates": [
[37.401249, -9.025150],
[37.431196, -7.463079],
[36.929082, -8.982059],
[37.028052, -7.290712]
]
}'
The polygon formed by coordinates ```[37.401249, -9.025150], [37.431196, -7.463079], [36.929082, -8.982059], [37.028052, -7.290712]``` delimits the Algarve area and the only dealer in that area in the provided dataset is `MB Albufeira`, so the the response will be:
{ "dealers": [ { "id": "846679bd-5831-4286-969b-056e9c89d74c", "name": "MB Albufeira", "latitude": 37.104404, "longitude": -8.236308, "closed": [ "friday", "wednesday" ], "vehicles": [ { "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "d5d0aabc-c0de-4f38-badc-759f96f5fca3", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "1cd6eae7-5f6f-42a7-a4ca-de7e498d9ce4", "model": "AMG", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } } ] } ] }
## Find Closest Dealers With Vehicle (Sorted)
Return the closest dealer closest to a specified location that has a
vehicle with certain attributes.
* **URL**
`/api/dealers?latitude=:latitude&longitude=:longitude&model=:model&fuel=:fuel&transmission=:transmission`
* **Method:**
`GET`
* **URL Params**
**Required:**
`latitude=[float]`
`longitude=[float]`
**Optional:**
`model=[string]`
`fuel=[string]`
`transmission=[string]`
* **Success Response:**
* **Code:** 200 <br />
**Content:** List of dealers wit the specified vehicle, sorted from
the closest one to the the furthest one or empty list.
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Message content here" }`
* **Sample Calls:**
curl -X GET
'http://localhost:8081/api/dealers?latitude=38.187787&longitude=-8.104157&model=amg&fuel=gasoline'
{ "dealers": [ { "id": "bbcdbbad-5d0b-45ef-90ac-3581b997e063", "name": "MB Lisboa", "latitude": 38.746721, "longitude": -9.229837, "closed": [ "sunday", "monday" ], "vehicles": [ { "id": "778a04fd-0a6a-4dc7-92bb-a7517608efc2", "model": "A", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "893d97bf-5a9d-4926-ace3-39ad0585c912", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "44a36bfa-ec8f-4448-b4c2-809203bdcb9e", "model": "E", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } }, { "id": "d723b0bd-8eb0-4826-bf5d-44754005d174", "model": "AMG", "fuel": "GASOLINE", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "wednesday": [ "1000", "1030" ] } } ] }, { "id": "846679bd-5831-4286-969b-056e9c89d74c", "name": "MB Albufeira", "latitude": 37.104404, "longitude": -8.236308, "closed": [ "friday", "wednesday" ], "vehicles": [ { "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "d5d0aabc-c0de-4f38-badc-759f96f5fca3", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "1cd6eae7-5f6f-42a7-a4ca-de7e498d9ce4", "model": "AMG", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } } ] } ] }
curl -X GET
'http://localhost:8081/api/dealers?latitude=38.187787&longitude=-8.104157&model=amg&fuel=gasoline&transmission=manual'
Response:
{ "dealers": [ { "id": "846679bd-5831-4286-969b-056e9c89d74c", "name": "MB Albufeira", "latitude": 37.104404, "longitude": -8.236308, "closed": [ "friday", "wednesday" ], "vehicles": [ { "id": "768a73af-4336-41c8-b1bd-76bd700378ce", "model": "E", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "d5d0aabc-c0de-4f38-badc-759f96f5fca3", "model": "AMG", "fuel": "ELECTRIC", "transmission": "AUTO", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } }, { "id": "1cd6eae7-5f6f-42a7-a4ca-de7e498d9ce4", "model": "AMG", "fuel": "GASOLINE", "transmission": "MANUAL", "availability": { "tuesday": [ "1000", "1030" ], "monday": [ "1000", "1030" ] } } ] } ] }
* **Notes**
I decided to go with `POST` instead of `GET`, because the list of coordinates
can get fairly long and `RFC 2616 Section 9.5` suggests this too.
## Create Booking
Creates a new booking for a vehicle. This request only succeeds if the vehicle is available for booking at the selected time , it's not already booked for that time and it exists.
* **URL**
`/api/bookings/create/`
Body:
{ "first_name": :first_name, "last_name": :last_name, "vehicle_id": :vehicle_id, "pickup_date": :pickup_date }
* **Method:**
`POST`
* **Data Params**
**Required**:
`first_name=[string]`
`last_name=[string]`
`vehicle_id=[string]`
`pickup_date=[string]`<br />
`pickup_date` is date in ISO format.
* **Success Response:**
* **Code:** 201 <br />
**Content:** the newly created booking
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Error message here." }`
* **Sample Call:**
curl -X POST
http://localhost:8081/api/bookings/create/
-d '{
"first_name": "Jayceon",
"last_name": "Taylor",
"vehicle_id": "136fbb51-8a06-42fd-b839-c01ab87e2c6c",
"pickup_date": "2019-04-08T10:30:00"
} '
Response:
{ "id": "04e18713-49f5-4022-b1b3-32ed0371dcaa", "firstName": "Jayceon", "lastName": "Taylor", "vehicleId": "136fbb51-8a06-42fd-b839-c01ab87e2c6c", "pickupDate": "2019-04-08T10:30:00", "createdAt": "2018-03-13T22:06:54.454664" }
## Cancel Booking
Cancel an existing vehicle booking. This requests only succeeds if the booking exists and has not already been canceled. After canceling a booking the vehicle becomes available for that time slot again.
* **URL**
`/api/bookings/cancel/`
Body:
{ "booking_id": :booking_id, "reason": :reason }
Example body:
{ "booking_id": "b00d3e76-9605-49c7-910b-03b51679f6d6", "reason": "It's my cat's birthday." }
* **Method:**
`PUT`
* **Data Params**
**Required**:
`booking_id=[string]`
`reason=[string]`
Example
* **Success Response:**
* **Code:** 200 <br />
**Content:** the cancelled booking object
* **Error Response:**
* **Code:** 400 BAD REQUEST <br />
**Content:** `{ error : "Error message here." }`
* **Sample Call:**
curl -X PUT
http://localhost:8081/api/bookings/cancel/
-d '{
"booking_id": "b00d3e76-9605-49c7-910b-03b51679f6d6",
"reason": "It'''s my cat'''s birthday."
}'
Response:
{ "id": "04e18713-49f5-4022-b1b3-32ed0371dcaa", "firstName": "Jayceon", "lastName": "Taylor", "vehicleId": "136fbb51-8a06-42fd-b839-c01ab87e2c6c", "pickupDate": "2019-04-08T10:30:00", "createdAt": "2018-03-13T22:06:54.454664" }