Document how to build using Bazel

[pedrokiefer]

After a few rounds of Bazel errors, this is what worked for me:

In MODULE.bazel:

bazel_dep(
    name = "proxy-wasm-cpp-sdk",
    version = "0.0.0",
    repo_name = "proxy_wasm_cpp_sdk",
)

# Use git_override for proxy-wasm-cpp-sdk
git_override(
    module_name = "proxy-wasm-cpp-sdk",
    remote = "https://github.com/proxy-wasm/proxy-wasm-cpp-sdk.git",
    commit = "e5256b0c5463ea9961965ad5de3e379e00486640",
)

In the BUILD with the source code:

load("@proxy_wasm_cpp_sdk//bazel:defs.bzl", "proxy_wasm_cc_binary")

licenses(["notice"])  # Apache 2

proxy_wasm_cc_binary(
    name = "http_wasm_example.wasm",
    srcs = ["http_wasm_example.cc"],
    copts = ["-std=c++20"],
)

then running bazel build //src:http_wasm_example.wasm worked perfectly. Now it's just a matter of creating a scratch image with the built wasm file.

[martijneken]

ACK to the missing documentation. So far it's only shown in example/BUILD.

There is a MODULE.bazel file in the repo (added recently).

Why did you need the git_override to pin a revision?

[pedrokiefer]

Without the git_override it fails with this message:

ERROR: Error computing the main repository mapping: module proxy-wasm-cpp-sdk@0.0.0 not found in registries:
* https://bcr.bazel.build/modules/proxy-wasm-cpp-sdk/0.0.0/MODULE.bazel: not found