This is a bare-bones example of how to make an Azure function in C++. It contains one http trigger and one queue trigger that binds to a local Azurite instance. The http trigger returns the http body and the queue trigger echoes the message to stdout.
The example uses crow to set up the web server for simplicity. The project may be used further in the future to investigate if it is possible to use other Azure services that are usually integrated in an Azure function.
Not sure yet if it will work in the cloud as-is, or if you need to e.g. put it in a docker container first.
Requires Azure functions core tools and a running Azurite emulator to run locally. In Azurite the queue trigger test needs a queue called test-queue to bind to.
- Compile
cd <cmake-folder>func start
The function host exposes some settings to our function via environment variables. These are called FUNCTIONS_* or FUNCTIONS_CUSTOMHANDLER_*.
The port we are supposed to listen to in order to communicate with the host is found in FUNCTIONS_CUSTOMHANDLER_PORT.
On start, the function host will send the following request to the worker/handler:
GET / HTTP/1.1
Host: 127.0.0.1:XXX
I'm not sure yet what is the appropriate way to respond to this, but currently the example is returning an empty OK response and it seems the host is accepting this.
If we set the flag enableForwardingHttpRequest in host.json the function host will send a copy of incoming requests
to our function, which can come in handy if we only need http triggers. Turning this off adds extra structure to the
requests coming from the function host.
The initial version of this test made use of the enableForwardingHttpRequest. Note that the route changes when using this setting.
- https://learn.microsoft.com/en-us/azure/azure-functions/create-first-function-vs-code-other?tabs=go%2Clinux
- Official documentation
- https://learn.microsoft.com/en-us/azure/azure-functions/functions-triggers-bindings?tabs=isolated-process%2Cnode-v4%2Cpython-v2&pivots=programming-language-csharp#bindings-code-examples
- Examples of bindings of various types
- https://www.youtube.com/watch?v=2hNdkYInj4g
- Minimal video demonstrating how to do this in Go
- https://think-async.com/Asio/asio-1.30.2/doc/asio/tutorial/tutdaytime1.html
- The web server is based on this