refactor, update README

variables:

  GIT_STRATEGY: clone

  CONTAINER_RDM_URL: "${NDIP_DOCKER_REPOSITORY}/${CI_PROJECT_PATH}/remote-data-broker"

  TAG: 0.5.1

  TAG: 0.5.2

# This import is for the func_rse_docker_* functions

before_script:

set (exe_name "${TARGET_NAME}")

add_custom_target(remote-data-broker ALL

    COMMAND go build ${GO_OPTS} -o ${CMAKE_CURRENT_BINARY_DIR}/${exe_name} main/rdb.go

    COMMAND go build ${GO_OPTS} -o ${CMAKE_CURRENT_BINARY_DIR}/${exe_name} main/main.go

    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/src

    VERBATIM)

define_property(TARGET PROPERTY EXENAME

set(CPACK_PACKAGE_VERSION_MAJOR "0")

set(CPACK_PACKAGE_VERSION_MINOR "5")

set(CPACK_PACKAGE_VERSION_PATCH "1")

set(CPACK_PACKAGE_VERSION_PATCH "2")

INCLUDE(CPack)

MIT License

Copyright (c) 2024 UT-Battelle, LLC

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

# Remote Data Broker

Remote Data Broker a is a low-level service within NDIP 

data management solution that is responsible

for serving files to other NDIP components using HTTP protocol.

Remote Data Broker is a low-level service within the NDIP data management solution responsible for serving files to

other NDIP components using the HTTP protocol. It is primarily used when files are not available locally and need to be

transferred from another location. Additionally, it provides the capability to delete remote files.

It is usually used when the files are not available locally but need to be

transferred from some other location.

 No newline at end of file

## Architecture

The broker consists of two main components:

1. **Server** – Handles HTTP requests and serves files directly or redirects them to the client via RabbitMQ. 

2. **Client** (optional) – Listens to a RabbitMQ (RMQ) queue and processes requests in cases where the broker runs on a

   machine restricted by firewall rules from accepting inbound HTTP connections.

## File Access Modes

- If the request is processed by the client, it is assumed to have direct access to the files.

- If the request is processed by the server, access is managed in two ways, depending of a query parameter in the request:

    - As the user running the service.

    - On behalf of another user via an OIDC token provided in the HTTP request.

For the latter, we use the [oidc-run-as-user](https://code.ornl.gov/ndip/ssh-oidc) utility.

## Configuration

Both the server and client are configured using a JSON file. See the example configuration file [here](conf.sample.json).

## Running the Service

The service is containerized using Docker. To build the image, run:

```bash

docker build -f dockerfiles/Dockerfile -t rdb .

```

To run the service, use:

```bash

docker run -it -p 9000:9000 -v <path to config file>:/config.json rdb /remote-data-broker -config /config.json

```

## REST API

After you start a docker container (see above), you can access the REST API documentation at the address:

http://localhost:9000/swagger/

In NDIP, the Remote Data Broker is used internally by Rucio, via an extra [protocol](https://code.ornl.gov/ndip/rucio-protocols) so there is no need to directly interact with it.

## License

See [License File](LICENSE.txt)

{

  "CatCommand": "oidc-run-as-user oidc-pam.json $token -f $filename",

  "TestCommand": "oidc-run-as-user oidc-pam.json $token -c 'test -r $filename'",

  "DeleteCommand": "oidc-run-as-user oidc-pam.json $token -c 'rm -f $filename'",

  "Auth": {

    "Enabled": true,

    "JwksUrls": [

      "https://login.microsoftonline.com/xxx/discovery/v2.0/keys"

    ],

    "UserFields": [

      "username",

      "preferred_username"

    ],

    "UserList": [

      "usdr"

    ]

  },

  "Http": {

    "Enabled": true,

    "EndpointUrl": "http://127.0.0.1:9000",

    "Port": 9000,

    "ChunkSize": 100000,

    "Timeout": 30

  },

  "Rmq": {

    "Url": "amqp://guest:guest@127.0.0.1:5672"

  },

  "RmqClient": {

    "Enabled": true,

    "Queue": "test"

  },

  "LogSettings": {

    "Level": "debug",

    "LogToFile": true,

    "FileFolder": "/tmp"

  }

}