docker-http-https-echo

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mendhak/http-https-echo is a Docker image that can echo various HTTP request properties back to client, as well as in the Docker container logs. You can use your own certificates, choose your ports, decode JWT headers and filter out certain paths.

This image is executed as non root by default and is fully compliant with Kubernetes or Openshift deployment.

Please do not use the :latest tag as it will break without warning, use a specific version instead.

Basic Usage

Run with Docker

docker run -p 8080:8080 -p 8443:8443 --rm -t mendhak/http-https-echo:24

Or run with Docker Compose

docker-compose up

Then, issue a request via your browser or curl, and watch the response, as well as container log output.

curl -k -X PUT -H "Arbitrary:Header" -d aaa=bbb https://localhost:8443/hello-world

Choose your ports

You can choose a different internal port instead of 8080 and 8443 with the HTTP_PORT and HTTPS_PORT environment variables.

In this example I'm setting http to listen on 8888, and https to listen on 9999.

 docker run -e HTTP_PORT=8888 -e HTTPS_PORT=9999 -p 8080:8888 -p 8443:9999 --rm -t mendhak/http-https-echo:24

With docker compose, this would be:

my-http-listener:
    image: mendhak/http-https-echo:24
    environment:
        - HTTP_PORT=8888
        - HTTPS_PORT=9999
    ports:
        - "8080:8888"
        - "8443:9999"

Use your own certificates

Use volume mounting to substitute the certificate and private key with your own. This example uses the snakeoil cert.

my-http-listener:
    image: mendhak/http-https-echo:24
    ports:
        - "8080:8080"
        - "8443:8443"
    volumes:
        - /etc/ssl/certs/ssl-cert-snakeoil.pem:/app/fullchain.pem
        - /etc/ssl/private/ssl-cert-snakeoil.key:/app/privkey.pem

Decode JWT header

If you specify the header that contains the JWT, the echo output will contain the decoded JWT. Use the JWT_HEADER environment variable for this.

docker run -e JWT_HEADER=Authentication -p 8080:8080 -p 8443:8443 --rm -it mendhak/http-https-echo:24

Now make your request with Authentication: eyJ... header (it should also work with the Authentication: Bearer eyJ... schema too):

 curl -k -H "Authentication: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c" http://localhost:8080/

And in the output you should see a jwt section.

Disable ExpressJS log lines

In the log output set the environment variable DISABLE_REQUEST_LOGS to true, to disable the specific ExpressJS request log lines. The ones like ::ffff:172.17.0.1 - - [03/Jan/2022:21:31:51 +0000] "GET /xyz HTTP/1.1" 200 423 "-" "curl/7.68.0". The JSON output will still appear.

docker run --rm -e DISABLE_REQUEST_LOGS=true --name http-echo-tests -p 8080:8080 -p 8443:8443 -t mendhak/http-https-echo:24

Do not log specific path

Set the environment variable LOG_IGNORE_PATH to a path you would like to exclude from verbose logging to stdout. This can help reduce noise from healthchecks in orchestration/infrastructure like Swarm, Kubernetes, ALBs, etc.

 docker run -e LOG_IGNORE_PATH=/ping -p 8080:8080 -p 8443:8443 --rm -t mendhak/http-https-echo:24

With docker compose, this would be:

my-http-listener:
    image: mendhak/http-https-echo:24
    environment:
        - LOG_IGNORE_PATH=/ping
    ports:
        - "8080:8080"
        - "8443:8443"

JSON payloads and JSON output

If you submit a JSON payload in the body of the request, with Content-Type: application/json, then the response will contain the escaped JSON as well.

For example,

curl -X POST -H "Content-Type: application/json" -d '{"a":"b"}' http://localhost:8080/

Will contain a json property in the response/output.

    ...
    "xhr": false,
    "connection": {},
    "json": {
        "a": "b"
    }
}

Send an empty response

You can disable the JSON output in the response by setting the environment variable ECHO_BACK_TO_CLIENT. For example,

docker run -e ECHO_BACK_TO_CLIENT=false -p 8080:8080 -p 8443:8443 --rm -t mendhak/http-https-echo:24

Custom status code

Use x-set-response-status-code to set a custom status code.

You can send it as a header:

curl -v -H "x-set-response-status-code: 401" http://localhost:8080/

You can send it as a querystring parameter:

curl -v http://localhost:8080/some/path?x-set-response-status-code=401

That will cause the reponse status code to be:

 HTTP/1.1 401 Unauthorized

Add a delay before response

Use x-set-response-delay-ms to set a custom delay in milliseconds. This will allow you to simulate slow responses.

You can send it as a header:

curl -v -H "x-set-response-delay-ms: 6000" http://localhost:8080/

You can send it as a querystring parameter:

curl -v http://localhost:8080/some/path?x-set-response-delay-ms=6000

Only return body in the response

Use the querystring parameter, response_body_only=true to get just the request body in the response, none of the associated metadata.

curl -s -k -X POST -d 'cauliflower' http://localhost:8080/a/b/c?response_body_only=true

The output will be 'cauliflower'.

Output

Curl output

docker logs output

Building

docker build -t mendhak/http-https-echo .

Run some tests to make sure features are working as expected.

./tests.sh

To create a new image on Docker Hub, I need to create a tag and push it.

git tag -s 16
git push --tags

Changelog

See the changelog