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fuchsia / fuchsia / refs/heads/main / . / examples / fidl / calculator
tree: 1827cb258e0e451612dd16b492e24e3737d57147 [path history] [tgz]
  1. cpp/
  2. fidl/
  3. realm/
  4. rust/
  5. BUILD.gn
  6. input.txt
  7. README.md
examples/fidl/calculator/README.md

Calculator example

Reviewed on 2022-10-7

This directory contains the necessary Fuchsia components to run a client/server implementation of a calculator.

The main goals of this example are to:

  • Demonstrate communicating between Fuchsia components using FIDL.
  • Demonstrate FIDL best practices.
  • Be realistic, even if it means more complex code.

Building

The build steps differ slightly depending on if you‘re using the rust or c++ version of the code. Both are functionally the same, so use the language you’re most familiar with or interested in.

To add this project to your build, append the following to your fx set invocation:

fx set workstation_eng.x64\
    --with //examples/fidl/calculator:all\
    --with //examples/fidl/calculator:tests

and then build:

fx build

Running

Start the emulator and package server.

  1. start the emulator:
ffx emu start --headless workstation_eng.x64
  1. start the package server:
fx serve

After the emulator & package server are running, the instructions differ based on language.

Rust

Between, client, server, fidl, and realm, all necessary services are provided to run a simple calculator on Fuchsia.

To run these components together add calculator-example-rust to the ffx-laboratory:

ffx component create /core/ffx-laboratory:calculator-example-rust \
    fuchsia-pkg://fuchsia.com/calculator-example-rust#meta/calculator_realm.cm

and then start the component:

ffx component start /core/ffx-laboratory:calculator-example-rust
ffx component start /core/ffx-laboratory:calculator-example-rust/client

C++

Between, client, server, fidl, and realm, all necessary services are provided to run a simple calculator on Fuchsia.

To run these components together add calculator-example-cpp to the ffx-laboratory:

ffx component create /core/ffx-laboratory:calculator-example-cpp \
    fuchsia-pkg://fuchsia.com/calculator-example-cpp#meta/calculator_realm.cm

and then start the component:

ffx component start /core/ffx-laboratory:calculator-example-cpp
ffx component start /core/ffx-laboratory:calculator-example-cpp/client

To see the output, use ffx log:

ffx log --filter calculator

You should see output like the following:

  • Rust
[186076.236][pkg-resolver][pkg-resolver][I] resolved fuchsia-pkg://fuchsia.com/calculator-example-rust as fuchsia-pkg://default/calculator-example-rust to 0e02791fffe45549315e420ee5bbcd4de6b8002f9e791b55cb6a09439faee266 with TUF
[186076.374][client][][I] 1 + 1 = 2
[186076.376][client][][I] -1 + -1 = -2
[186076.377][client][][I] 3.333 + 4.444 = 7.777
[186076.379][client][][I] 4 - 4 = 0
[186076.380][client][][I] 5.67 * 8.39 = 47.5713
[186076.381][client][][I] 15.07 / 7.23 = 2.0843706777316733
[186076.383][client][][I] 2 ^ 16 = 65536
  • C++
[185909.783][pkg-resolver][pkg-resolver][I] resolved fuchsia-pkg://fuchsia.com/calculator-example-cpp as fuchsia-pkg://default/calculator-example-cpp to 1d272f44d34d8b44084d5a3ccd78ec6c4688ba62579d87ed4e0437d5a46d143b with TUF
[185909.825][client][calculator_client][I]: [main.cc:54] Calculator client: operator()():  got response 2
[185909.825][client][calculator_client][I]: [main.cc:54] Calculator client: operator()():  got response -2
[185909.825][client][calculator_client][I]: [main.cc:54] Calculator client: operator()():  got response 7.777
[185909.825][client][calculator_client][I]: [main.cc:70] Calculator client: operator()():  got response 0
[185909.825][client][calculator_client][I]: [main.cc:86] Calculator client: operator()():  got response 47.5713
[185909.825][client][calculator_client][I]: [main.cc:102] Calculator client: operator()():  got response 2.08437
[185909.825][client][calculator_client][I]: [main.cc:117] Calculator client: operator()():  got response 65536
[185909.825][client][calculator_client][I]: [main.cc:154] Received all responses, shutting down client
[185909.824][server][calculator_server][I]: [main.cc:147] C++ calculator server has started!
[185909.825][server][calculator_server][I]: [main.cc:46] Calculator server: Add() a=1 b=1
[185909.825][server][calculator_server][I]: [main.cc:46] Calculator server: Add() a=-1 b=-1
[185909.825][server][calculator_server][I]: [main.cc:46] Calculator server: Add() a=3.333 b=4.444
[185909.825][server][calculator_server][I]: [main.cc:60] Calculator server: Subtract() a=4 b=4
[185909.825][server][calculator_server][I]: [main.cc:74] Calculator server: Multiply() a=5.67 b=8.39
[185909.825][server][calculator_server][I]: [main.cc:85] Calculator server: Divide()  dividend = 15.07 divisor=7.23
[185909.825][server][calculator_server][I]: [main.cc:96] Calculator server: Pow() base=2 exponent=16

Testing

There are tests for both the client and server. The command for running tests differs slightly depending on the language used.

Rust

Client

To run the client tests, ensure you have an available Fuchsia target (ex: ffx emu start) and are serving packages (ex: fx serve) then run the following:

fx test calculator-client-rust-unittests

Server

To run the server tests, ensure you have an available Fuchsia target (ex: ffx emu start) and are serving packages (ex: fx serve) then run the following:

fx test calculator-server-rust-unittests

C++

Client

To run the client tests, ensure you have an available Fuchsia target (ex: ffx emu start) and are serving packages (ex: fx serve) then run the following:

fx test calculator-client-cpp-parser-unittests

TODO(https://fxbug.dev/42059966): Create client side FIDL unit tests once the TestBase exists for Natural bindings.

Server

To run the integration tests, which uses the C++ server as the component under test, run the following:

fx test calculator-integration-test-cpp

Source Layout

The source is split into several parts:

  1. fidl - defines the calculator FIDL protocol.
  2. realm - wires up the FIDL, client, and server components together.
  3. client - connects to a calculator FIDL protocol implementation and sends requests.
  1. server - implements the calculator FIDL protocol and receives requests.
  1. integration tests - Sets up a static realm with the server as the component under test