Examples

Overview

We have prepared some examples to help you implement your first Sandboxed API library.

You can find them in //sandboxed_api/examples, see below for detailed explanations.

Note: In the summer of 2020, Google interns created a number of SAPI sandboxed versions of open-source libraries which are available for download on GitHub.

hello_sapi

This is a very basic example which illustrates how SAPI works. The hello_lib.cc implements one function, AddTwoIntegers(), which will be sandboxed and called in the Host Code.

The second Host Code file, hello_transacted.cc, demonstrates an example use of SAPI Transactions.

Sum

A demo library implementing a few C functions and a single C++ function. It uses protobufs to exchange data between Host Code and the SAPI Library.

• The sandbox definition can be found in the sandbox.h file.
• The (automatically generated) function annotation file (a file providing prototypes of sandboxed functions) can be found in bazel-out/genfiles/sandboxed_api/examples/sum/lib/sum-sapi.sapi.h after a Bazel build.
• The actual execution logic (a.k.a. Host Code) which makes use of the exported sandboxed procedures can be found in main_sum.cc.

zlib

This is a demo implementation (functional, but currently not used in production) for the zlib library, exporting some of its functions and making them available to the Host Code.

The demonstrated functionality of the Host Code is decoding of zlib streams from stdin to stdout.

This SAPI library doesn't use the sandbox.h file, as it uses the default Sandbox2 policy, and an embedded SAPI library, so there is no need to provide the sapi::Sandbox::GetLibPath() or the sapi::Sandbox::GetPolicy() method.

The zlib SAPI can be found in //sapi_sandbox/examples/zlib, along with its Host Code.

stringop

This example demonstrates the use of protobufs to provide a string reverse and duplication function. The library also contains a dedicated sandbox.h to provide a stricter Sandbox Policy.

The Host Code doesn't represent a “normal”program, instead it demonstrates the functionality of the SAPI library using unit tests.

In this example, the non-protobuf based functions are also included to provide a comparison between the two approaches.