Ankur's Exchange Rate Server Service for Curve

This will look at the exchange of currencies between EUR, USD and GBP:

1. Get today's exchange value from currency1 to currency2.
2. Get last week's exchange value from currency1 to currency2.
3. Perform a naive comparison between the two to determine if today is a good time to exchange currency1 into currency2.
4. Return the results -- single unit of curreny1 to curreny2 and the result of the naive comparison.

API

Request - /v1/exchange?from={"EUR", "USD", "GBP"}&to={"EUR", "USD", "GBP"}

Type: GET

Query parameter: from (required)
Valid values: {"EUR", "USD", "GBP"}

Query parameter: to (required)
Valid values: {"EUR", "USD", "GBP"}

Response

Status: 200
Body: {"dataDateTime":"2019-10-14T19:21:48.11587894+01:00","from":"EUR","shouldExchange":false,"singleUnit":1.1031,"to":"USD"}

Status: 400
Body: {"reason":"query params are invalid. EUR, USD and GBP are valid."}

Status: 500
Body: {"reason":""}

cURL

Request:

curl http://localhost:8080/v1/exchange?from=EUR\&to=USD -v

Response:

*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /v1/exchange?from=EUR&to=USD HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.58.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Content-Type: application/json; charset=utf-8
< Date: Mon, 14 Oct 2019 18:28:54 GMT
< Content-Length: 122
< 
{"dataDateTime":"2019-10-14T19:28:54.823492804+01:00","from":"EUR","shouldExchange":false,"singleUnit":1.1031,"to":"USD"}
* Connection #0 to host localhost left intact

Build

The following will build and place a binary file in the release/1.0.0/ directory:

./build.sh

Run

Run with:

./release/1.0.0/exchange-1.0.0

Tests

To run all tests:

go test ./...

Bugs and Improvements

1. 500 response with no reason in json response body.
2. Requires logging to be implemented.
3. Requires Cobra and Viper integration.
4. More unit tests around failure cases, especially when a thread is getting data from network and other threads have to use stale data.
5. Integration tests.

Test Environment

This was tested and working on:

• Lenovo ThinkPad X1 Carbon - Core i7-4600U - 8 GB Ram
• Ubuntu 18.04.3 LTS (binoic)