Allow using static bindgen feature (#939)

Author: Congyuwang

.github/workflows/rust.yml

@@ -46,7 +46,16 @@ jobs:
           components: clippy
 
       - name: Run clippy
-        run: cargo clippy --all --all-targets -- -Dwarnings
+        run: |
+          cargo clippy --all-targets --features \
+            "jemalloc \
+            io-uring \
+            valgrind \
+            mt_static \
+            rtti \
+            multi-threaded-cf \
+            serde1" \
+            -- -D warnings
 
   audit:
     name: Security audit

Cargo.toml

@@ -19,7 +19,7 @@ exclude = [".gitignore", ".travis.yml", "deploy.sh", "test/**/*"]
 members = ["librocksdb-sys"]
 
 [features]
-default = ["snappy", "lz4", "zstd", "zlib", "bzip2"]
+default = ["snappy", "lz4", "zstd", "zlib", "bzip2", "bindgen-runtime"]
 jemalloc = ["rust-librocksdb-sys/jemalloc"]
 io-uring = ["rust-librocksdb-sys/io-uring"]
 valgrind = []
@@ -34,10 +34,14 @@ multi-threaded-cf = []
 serde1 = ["serde"]
 malloc-usable-size = ["rust-librocksdb-sys/malloc-usable-size"]
 zstd-static-linking-only = ["rust-librocksdb-sys/zstd-static-linking-only"]
+bindgen-runtime = ["rust-librocksdb-sys/bindgen-runtime"]
+bindgen-static = ["rust-librocksdb-sys/bindgen-static"]
 
 [dependencies]
 libc = "0.2"
-rust-librocksdb-sys = { path = "librocksdb-sys", version = "0.29.0" }
+rust-librocksdb-sys = { path = "librocksdb-sys", version = "0.29.0", default-features = false, features = [
+    "static",
+] }
 serde = { version = "1", features = ["derive"], optional = true }
 
 [dev-dependencies]

README.md

@@ -111,4 +111,22 @@ compression will cause Rocksdb to hold digested dictionaries in block cache to
 save repetitive deserialization overhead. This saves a lot of CPU for read-heavy
 workloads. This feature is gated behind a flag in Rocksdb because one of the
 digested dictionary APIs used is marked as experimental. However, this feature
-is still used at facebook in production per the [Preset Dictionary Compression Blog Post](https://rocksdb.org/blog/2021/05/31/dictionary-compression.html).
+is still used at facebook in production per the [Preset Dictionary Compression
+Blog Post](https://rocksdb.org/blog/2021/05/31/dictionary-compression.html).
+
+### Switch between static and dynamic linking for bindgen (features `bindgen-static` and `bindgen-runtime`)
+
+The feature `bindgen-runtime` will enable the `runtime` feature of bindgen, which dynamically
+links to libclang. This is suitable for most platforms, and is enabled by default.
+
+The feature `bindgen-static` will enable the `static` feature of bindgen, which statically
+links to libclang. This is suitable for musllinux platforms, such as Alpine linux.
+To build on Alpine linux for example, make these changes to your Cargo.toml:
+
+```toml
+[dependencies.rocksdb]
+default-features = false
+features = ["bindgen-static", "snappy", "lz4", "zstd", "zlib", "bzip2"]
+```
+
+Notice that `runtime` and `static` features are mutually exclusive, and won't compile if both enabled.

librocksdb-sys/Cargo.toml

@@ -28,9 +28,11 @@ exclude = [
 ]
 
 [features]
-default = ["static"]
+default = ["static", "bindgen/runtime"]
 jemalloc = ["tikv-jemalloc-sys"]
 static = ["libz-sys?/static", "bzip2-sys?/static"]
+bindgen-runtime = ["bindgen/runtime"]
+bindgen-static = ["bindgen/static"]
 mt_static = []
 io-uring = ["pkg-config"]
 snappy = []
@@ -58,6 +60,6 @@ uuid = { version = "1", features = ["v4"] }
 
 [build-dependencies]
 cc = { version = "1.0", features = ["parallel"] }
-bindgen = { version = "0.69", default-features = false, features = ["runtime"] }
+bindgen = { version = "0.69", default-features = false }
 glob = "0.3"
 pkg-config = { version = "0.3", optional = true }