From 8498348fcf1aad531c790e638b244c1cc4b5f980 Mon Sep 17 00:00:00 2001
From: Pratik Tripathy <mail@pratik.live>
Date: Tue, 28 Oct 2025 21:45:27 +0530
Subject: [PATCH] feat(snippet): Snippet for Dockerfile for rust app

- With sccache & cargo-chef for faster builds
- Docker cache-mount
- Auto copy required shared-libraries to final image
- Use debian 13 base image to use glibc & NOT musl
- CA certs, zoneinfo, nsswitch copied to final image
---
 .../nvim/custom-snippets/dockerfile.json      | 72 ++++++++++++++++++-
 1 file changed, 70 insertions(+), 2 deletions(-)

diff --git a/common/.config/nvim/custom-snippets/dockerfile.json b/common/.config/nvim/custom-snippets/dockerfile.json
index 14b2657..617112f 100644
--- a/common/.config/nvim/custom-snippets/dockerfile.json
+++ b/common/.config/nvim/custom-snippets/dockerfile.json
@@ -1,6 +1,6 @@
 {
     "Add User in Debian": {
-        "prefix": "userd",
+        "prefix": "adduser-debian",
         "description": "Add User to Debian Container",
         "body": [
             "RUN groupadd -r ${1:username} && useradd -m -r -g ${1:username} ${1:username}",
@@ -10,7 +10,7 @@
         ]
     },
     "Add User in Alpine": {
-        "prefix": "usera",
+        "prefix": "adduser-alpine",
         "description": "Add User to Alpine Container",
         "body": [
             "RUN addgroup -S ${1:username} && adduser -S ${1} -G ${1}",
@@ -18,5 +18,73 @@
             "WORKDIR \/${2:workdir}",
             "RUN chown ${1}:${1} \/${2}"
         ]
+    },
+    "Scratch Based Optimized Rust": {
+        "prefix": "rust-scratch",
+        "description": "Template for a Rust binary served from Docker",
+        "body": [
+            "# syntax=docker/dockerfile:1",
+            "ARG RUST_VERSION=1.90.0",
+            "FROM rust:\\${RUST_VERSION\\}-slim-trixie as builder",
+            "",
+            "# Install sccache & its dependencies",
+            "# hadolint ignore=DL3008",
+            "RUN apt-get update && apt-get install --no-install-recommends -y \\\\",
+            "    pkg-config \\\\",
+            "    libssl-dev \\\\",
+            "    && rm -rf /var/lib/apt/list/* \\\\",
+            "    && cargo install sccache cargo-chef --locked",
+            "",
+            "# Configure sccache",
+            "ENV RUSTC_WRAPPER=sccache \\\\",
+            "    SCCACHE_DIR=/sccache \\\\",
+            "    CARGO_HOME=/usr/local/cargo",
+            "",
+            "WORKDIR /app",
+            "",
+            "# Copy dependency files first for better layer caching",
+            "COPY Cargo.toml Cargo.lock ./",
+            "RUN cargo chef prepare --recipe-path recipe.json",
+            "",
+            "# Build dependencies with cache mounts",
+            "RUN --mount=type=cache,target=${CARGO_HOME}/registry,sharing=locked \\\\",
+            "    --mount=type=cache,target=${CARGO_HOME}/git,sharing=locked \\\\",
+            "    --mount=type=cache,target=${SCCACHE_DIR},sharing=locked \\\\",
+            "    cargo chef cook --release --recipe-path recipe.json",
+            "",
+            "# Copy source code and build application",
+            "COPY . .",
+            "RUN --mount=type=cache,target=${CARGO_HOME}/registry,sharing=locked \\\\",
+            "    --mount=type=cache,target=${CARGO_HOME}/git,sharing=locked \\\\",
+            "    --mount=type=cache,target=${SCCACHE_DIR},sharing=locked \\\\",
+            "    cargo build --release",
+            "",
+            "# Find & extract library dependency tree using \"ldd\"",
+            "# hadolint ignore=DL4006,SC2016",
+            "RUN mkdir -p /app/deps && \\\\",
+            "    find target/release -maxdepth 1 -type f -executable -exec ldd {} \\\\; | \\\\",
+            "    awk '/\\\\//{print $(NF-1)}' | \\\\",
+            "    xargs -I % sh -c 'mkdir -p /app/deps$(dirname %); cp % /app/deps%;'",
+            "",
+            "####### Target Image",
+            "FROM scratch",
+            "",
+            "# Copy the library dependency tree",
+            "COPY --from=builder /app/deps /",
+            "",
+            "# System essentials",
+            "COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/",
+            "COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo",
+            "COPY --from=builder --chmod=1777 /tmp /tmp",
+            "COPY --from=builder /etc/nsswitch.conf /etc",
+            "COPY --from=builder /etc/group /etc",
+            "COPY --from=builder /etc/passwd /etc",
+            "",
+            "USER nobody",
+            "",
+            "WORKDIR /app",
+            "COPY --from=builder --chown=nobody:nogroup /app/target/release/${1:appname} /app",
+            "CMD [\"/app/${1}\"]"
+        ]
     }
 }