Proxy Service

A service to proxy requests to a given backend service.

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Go 1.17+

Clone

git clone [email protected]:janu-cambrelen/proxy-service.git

Run (Local)

Run either of the following from the same directory as this README (change values as needed).

With Flags

go run main.go \
-debug=true \
-host=localhost \
-port=8080 \
-target-url=http://jsonplaceholder.typicode.com/ \
-body-methods-only=true \
-reject-with=bad_message \
-reject-exact=true \
-reject-insensitive=false \
-request-delay=2

With .env File

echo \
'DEBUG=true
HOST="localhost"
PORT=8080
TARGET_URL=http://jsonplaceholder.typicode.com/
BODY_METHODS_ONLY=true
REJECT_WITH=bad_message
REJECT_EXACT=true
REJECT_INSENSITIVE=false
REQUEST_DELAY=2' > .env
go run main.go

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Docker

Build

docker build -t proxy-scratch . 

Run

docker run -p 8080:8080 -it --rm proxy-scratch \
-debug=true \
-host=0.0.0.0 \
-port=8080 \
-target-url=http://jsonplaceholder.typicode.com/ \
-body-methods-only=false \
-reject-with=bad_message \
-reject-exact=true \
-reject-insensitive=false \
-request-delay=2

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Overview / Usage

Target URL:

The target backend "service" is set using the TARGET_URL environment file setting or by the -target-url CLI flag. The server will fail to initialize if the target url is not provided.

If, for example, we wanted to hit the http://backend-service.com/user endpoint of our backend service we would set http://backend-service.com/ as our target URL.

The proxy server will handle routing and map the URI accordingly. Therefore, to hit the /user endpoint from the proxy server, the request should be made to http://proxy-service.com/user.

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Supported HTTP Methods and Content-Type:

This service only accepts POST, PUT, and PATCH requests if the BODY_METHODS_ONLY environment file setting or the body-methods-only CLI flag is set to true. Otherwise, this service is able to support other methods (including GET requests with query params etc.).

Also, all requests and responses should be of content type application/json.

The client will receive an error, detailing the issue, if the aforementioned is not conformed to.

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Request Filtering:

This service can reject requests from ever reaching the backend / target based on a specfied word or phrase contained within the REJECT_WITH environment file setting or by the reject-with CLI flag.

Whether this validation is concerned with an "exact" match or a "contains" match is determined by the REJECT_EXACT environment file setting or by the reject-exact CLI flag.

Finally, whether this check is case-sensitive is determined by the REJECT_INSENSITIVE environment file setting or by the reject-insensitive CLI flag.

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Consecutive Request Delay:

The service will delay its response by two seconds if consective requests, containing the same content (i.e., request body) and common set of headers, are received.

The delay can be changed via the REQUEST_DELAY environment file setting or by the -request-delay CLI flag. Only positive integer values are supported.

The server will fail to initialize if the REQUEST_DELAY value is negative; otherwise, if not set, it will default to two seconds.

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Sample Backend Service: https://jsonplaceholder.typicode.com/

Sample Request (successful)

curl --location --include --request PATCH 'http://localhost:8080/posts/1' \
--header 'Content-Type: application/json' \
--data-raw '{
    "body": "good_message"
}'

Sample Response (successful)

HTTP/1.1 200 OK
Content-Type: application/json
X-Proxy-Request-Id: 6ad80a7c-c132-4417-8323-fdfcaf7365e8
Date: Tue, 14 Dec 2021 02:06:27 GMT
Content-Length: 138

{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "good_message"
}

Sample Request (unsuccessful)

curl --location --include --request PATCH 'http://localhost:8080/posts/1' \
--header 'Content-Type: application/json' \
--data-raw '{
    "body": "bad_message"
}'

Sample Response (unsuccessful)

HTTP/1.1 401 Unauthorized
Content-Length: 62
Content-Type: application/json
Date: Tue, 14 Dec 2021 02:08:21 GMT

{"code":"401","msg":"rejected because `bad_message` found within request body"}

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Test

Unit Tests

go test ./internal/proxyserver -v 

End-to-End Tests

bash scripts/e2e.sh

or

./scripts/e2e.sh 

All

go test ./internal/proxyserver -v && ./scripts/e2e.sh 

NOTE: May need to chmod +x ./scripts/e2e.sh if you encounter permissions issue.

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Docs

Update documentation within the doc directory:

go doc --all cmd  > doc/cmd.txt 
go doc --all internal/proxyserver > doc/proxyserver.txt

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