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Also, separate out RPC encoding from application logic. Signed-off-by: Thomas Leonard <thomas.leonard@docker.com>
70 lines
2.4 KiB
Markdown
70 lines
2.4 KiB
Markdown
## https-unikernel example service
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This sample service implements an https web-server as a set of three components communicating using [Cap'n Proto RPC][].
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1. The `store` service accepts requests for web pages and returns the page content.
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2. The `http` service accepts HTTP connections over RPC and handles GET requests using `store`.
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3. The `tls` service accepts encrypted HTTPS connections and provides them as a plain-text stream to `http`.
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The protocols implemented by the services can be found in the `proto.capnp` file.
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The services can be run in separate processes so that they are isolated from each other.
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For example, only the `tls` component needs access to the private key, so
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a bug in the HTTP protocol decoder cannot leak the key.
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Although the example services are all written in OCaml, it should be possible to replace any of them with a different implementation written in any other language with Cap'n Proto RPC support.
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### Running the samples
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The easiest way to build and run is using Docker:
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make docker
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make docker-run
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Once inside the container, you can run all the services in a single process like this:
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https-unikernel-single
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You should be able to try out the service by opening <https://localhost:8443> in a browser.
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You can also run the service as three separate processes.
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The easiest way to do this is by creating multiple windows in `screen` (which is running by default in the Docker image).
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First, start the store:
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https-unikernel-store unix:/tmp/store.sock
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Then, create a new window (`Ctrl-A c`) and start the http service:
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https-unikernel-http unix:/tmp/http.sock --store=unix:/tmp/store.sock
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Finally, make another window and run the TLS terminator:
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https-unikernel-tls --http unix:/tmp/http.sock --port 8443
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### Testing with Python
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With the services running as separate processes (i.e. with socket files available), you can also invoke services from other languages.
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For example, using Python (make another screen split):
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```
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$ cd src
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$ python
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>>> import capnp
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>>> import proto_capnp
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>>> import socket
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>>> s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0)
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>>> s.connect('/tmp/store.sock')
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>>> client = capnp.TwoPartyClient(s)
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>>> store = client.bootstrap().cast_as(proto_capnp.Store)
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>>> r = store.get(['index.html'])
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>>> print r.wait()
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( ok = "<p>It works!</p><p>Powered by Irmin.</p>\n" )
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```
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(or just do `python src/test_store.py`)
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[Cap'n Proto RPC]: https://capnproto.org/rpc.html
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