Add support for static linking of sqlx

`sqlx` requires linking against OpenSSL twice:

- `sqlx-macros` needs to link against OpenSSL as a shared libary for use
  at compile time.
- `sqlx` needs to link against OpenSSL a static library for use at
  runtime.

You can find the details here:

https://github.com/launchbadge/sqlx/issues/670
https://github.com/sfackler/rust-openssl/issues/1337

We go with the fix proposed by @sfackler, and add a test program that we
can use to verify everything works correctly.

We remove a few `OPENSSL`-related variables that were added 4 years ago,
and that no longer appear to be needed.

Dockerfile

@@ -142,11 +142,8 @@ RUN echo "Building libpq" && \
     cd ../../bin/pg_config && make && sudo make install && \
     rm -r /tmp/*
 
-ENV OPENSSL_DIR=/usr/local/musl/ \
+ENV X86_64_UNKNOWN_LINUX_MUSL_OPENSSL_DIR=/usr/local/musl/ \
-    OPENSSL_INCLUDE_DIR=/usr/local/musl/include/ \
+    X86_64_UNKNOWN_LINUX_MUSL_OPENSSL_STATIC=1 \
-    DEP_OPENSSL_INCLUDE=/usr/local/musl/include/ \
-    OPENSSL_LIB_DIR=/usr/local/musl/lib/ \
-    OPENSSL_STATIC=1 \
     PQ_LIB_STATIC_X86_64_UNKNOWN_LINUX_MUSL=1 \
     PG_CONFIG_X86_64_UNKNOWN_LINUX_GNU=/usr/bin/pg_config \
     PKG_CONFIG_ALLOW_CROSS=true \

README.md

@@ -2,6 +2,8 @@
 
 [![Docker Image](https://img.shields.io/docker/pulls/ekidd/rust-musl-builder.svg?maxAge=2592000)](https://hub.docker.com/r/ekidd/rust-musl-builder/)
 
+[Source on GitHub](https://github.com/emk/rust-musl-builder)
+
 ## What is this?
 
 Do you want to compile a completely static Rust binary with no external dependencies?  If so, try:
@@ -13,7 +15,7 @@ rust-musl-builder cargo build --release
 
 This command assumes that `$(pwd)` is readable and writable by uid 1000, gid 1000. At the moment, it doesn't attempt to cache libraries between builds, so this is best reserved for making final release builds.
 
-For a more realistic example, see the `Dockerfile` for [examples/using-diesel](./examples/using-diesel).
+For a more realistic example, see the `Dockerfile` for [examples/using-diesel](./examples/using-diesel) [examples/using-sqlx](./examples/using-sqlx).
 
 ## Deploying your Rust application
 
@@ -36,7 +38,7 @@ In general, we provide the following tagged Docker images:
   Rust, please file an issue.
 
 At a minimum, each of these images should be able to
-compile [examples/using-diesel](./examples/using-diesel).
+compile [examples/using-diesel](./examples/using-diesel) and [examples/using-sqlx](./examples/using-sqlx).
 
 [comp]: https://rust-lang.github.io/rustup-components-history/index.html
 
@@ -94,8 +96,6 @@ This image also supports the following extra goodies:
 If your application uses OpenSSL, you will also need to take a few extra steps to make sure that it can find OpenSSL's list of trusted certificates, which is stored in different locations on different Linux distributions. You can do this using [`openssl-probe`](https://crates.io/crates/openssl-probe) as follows:
 
 ```rust
-extern crate openssl_probe;
-
 fn main() {
     openssl_probe::init_ssl_cert_env_vars();
     //... your code

examples/using-diesel/Cargo.toml

@@ -9,3 +9,4 @@ diesel = { version = "1", features = ["postgres", "sqlite"] }
 libsqlite3-sys = { version = "*", features = ["bundled"] }
 # Needed for Postgres.
 openssl = "*"
+openssl-probe = "0.1.2"

examples/using-diesel/src/main.rs

@@ -46,6 +46,8 @@ where
 }
 
 fn main() {
+    openssl_probe::init_ssl_cert_env_vars();
+
     println!("Hello, world!");
 
     // Only run our database example if we have a database. Otherwise, we just

examples/using-sqlx/.dockerignore

@@ -0,0 +1 @@
+target

examples/using-sqlx/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "using-sqlx"
+version = "0.1.0"
+authors = ["Eric Kidd <git@randomhacks.net>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+openssl-probe = "0.1.2"
+sqlx = { version = "0.4.0-beta.1", default-features = false, features = ["runtime-tokio", "macros", "offline", "postgres"] }
+tokio = { version = "0.2", features = ["macros"] }

examples/using-sqlx/Dockerfile

@@ -0,0 +1,25 @@
+# -*- mode: dockerfile -*-
+#
+# An example Dockerfile showing how to build a Rust executable using this
+# image, and deploy it with a tiny Alpine Linux container.
+
+# You can override this `--build-arg BASE_IMAGE=...` to use different
+# version of Rust or OpenSSL.
+ARG BASE_IMAGE=ekidd/rust-musl-builder:latest
+
+# Our first FROM statement declares the build environment.
+FROM ${BASE_IMAGE} AS builder
+
+# Add our source code.
+ADD --chown=rust:rust . ./
+
+# Build our application.
+RUN cargo build --release
+
+# Now, we need to build our _real_ Docker container, copying in `using-sqlx`.
+FROM alpine:latest
+RUN apk --no-cache add ca-certificates
+COPY --from=builder \
+    /home/rust/src/target/x86_64-unknown-linux-musl/release/using-sqlx \
+    /usr/local/bin/
+CMD /usr/local/bin/using-sqlx

examples/using-sqlx/docker-compose.yml

@@ -0,0 +1,12 @@
+version: "2.0"
+
+services:
+  app:
+    build: .
+    volumes:
+      - cargo:/home/rust/.cargo
+      - target:/home/rust/src/target
+
+volumes:
+  cargo: {}
+  target: {}

examples/using-sqlx/sqlx-data.json

@@ -0,0 +1,23 @@
+{
+  "db": "PostgreSQL",
+  "bf54a84704792059fc3a494889dce274bb09f5cadc8c7be61a9b85abbceb001f": {
+    "query": "SELECT $1::INTEGER AS value",
+    "describe": {
+      "columns": [
+        {
+          "ordinal": 0,
+          "name": "value",
+          "type_info": "Int4"
+        }
+      ],
+      "parameters": {
+        "Left": [
+          "Int4"
+        ]
+      },
+      "nullable": [
+        null
+      ]
+    }
+  }
+}

examples/using-sqlx/src/main.rs

@@ -0,0 +1,23 @@
+use std::env;
+
+use sqlx::{Connection, postgres::PgConnection};
+
+#[tokio::main]
+async fn main() -> Result<(), sqlx::Error> {
+    openssl_probe::init_ssl_cert_env_vars();
+
+    let url = env::var("POSTGRES_URL")
+        .unwrap_or_else(|_| "postgresql://postgres@localhost/postgres".to_owned());
+
+    // Create a connection.
+    let mut conn = PgConnection::connect(&url).await?;
+
+    // Make a simple query using the `query!` macro.
+    let row = sqlx::query!("SELECT $1::INTEGER AS value", 2i32)
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(row.value, Some(2));
+
+    Ok(())
+}

hooks/test

@@ -4,7 +4,7 @@
 set -euo pipefail
 
 # Make sure we can build some of our more important test images.
-for EXAMPLE in using-diesel; do
+for EXAMPLE in using-diesel using-sqlx; do
     docker build \
         --build-arg BASE_IMAGE="$IMAGE_NAME" \
         -t rust-musl-builder-"$EXAMPLE" \

test-image

@@ -41,6 +41,20 @@ fi
 echo -e '[PASS] ARMhf binary is statically linked.\n'
 "
 
+# Make sure we can build a static executable using `sqlx`.
+docker build -t rust-musl-builder-using-sqlx examples/using-sqlx
+docker run --rm rust-musl-builder-using-sqlx sh -c "
+set -euo pipefail
+
+echo -e '--- Test case for sqlx:'
+echo 'ldd says:'
+if ldd /usr/local/bin/using-sqlx; then
+  echo '[FAIL] Executable is not static!' 1>&2
+  exit 1
+fi
+echo -e '[PASS] using-sqlx binary is statically linked.\n'
+"
+
 # Make sure we can build a static executable using `git2`.
 docker build -t rust-musl-builder-linking-with-git2 examples/linking-with-git2
 docker run --rm rust-musl-builder-linking-with-git2 bash -c "