From 37d70c40c5655720eb0c1e044e461019c89d77a0 Mon Sep 17 00:00:00 2001
From: druppy <bl@lue.dk>
Date: Sat, 24 Oct 2026 21:23:30 +0200
Subject: [PATCH] Add sandbox crate + workflow to test ephemeral podman runners

---
 .gitea/workflows/sandbox.yml |  39 +++++++
 sandbox/Cargo.lock           | 214 +++++++++++++++++++++++++++++++++++
 sandbox/Cargo.toml           |  12 ++
 sandbox/src/lib.rs           |  49 ++++++++
 4 files changed, 314 insertions(+)
 create mode 100644 .gitea/workflows/sandbox.yml
 create mode 100644 sandbox/Cargo.lock
 create mode 100644 sandbox/Cargo.toml
 create mode 100644 sandbox/src/lib.rs

diff --git a/.gitea/workflows/sandbox.yml b/.gitea/workflows/sandbox.yml
new file mode 100644
index 0000000..9163f45
--- /dev/null
+++ b/.gitea/workflows/sandbox.yml
@@ -0,0 +1,39 @@
+name: Sandbox - ephemeral runner + shared cache
+on:
+  push:
+    branches: [ci/sandbox]
+  workflow_dispatch:
+
+jobs:
+  cargo:
+    runs-on: sandbox
+    defaults:
+      run:
+        working-directory: sandbox
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Where am I?
+        run: |
+          echo "runner : ${RUNNER_NAME}"
+          echo "os     : $(grep PRETTY_NAME /etc/os-release | cut -d'"' -f2)"
+          echo "uid    : $(id -u)  cgroup: $(head -c 40 /proc/self/cgroup)"
+          command -v git >/dev/null && echo "git    : $(git --version)"
+
+      - name: Toolchain
+        run: |
+          command -v cargo >/dev/null || { apt-get update -qq && apt-get install -y -qq --no-install-recommends rustc cargo >/dev/null; }
+          cargo --version
+
+      - name: Cache cargo deps and target
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            sandbox/target
+          key: cargo-${{ hashFiles('sandbox/Cargo.lock') }}
+          restore-keys: cargo-
+
+      - name: Test
+        run: cargo test 2>&1 | tail -6
diff --git a/sandbox/Cargo.lock b/sandbox/Cargo.lock
new file mode 100644
index 0000000..63278e1
--- /dev/null
+++ b/sandbox/Cargo.lock
@@ -0,0 +1,214 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "anyhow"
+version = "1.0.104"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "330a5ed07fa54e4702c9d6c4174f74427fc0ef6e214bbd677ae50a5099946470"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
+
+[[package]]
+name = "ci-sandbox"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "rand",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "itoa"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
+
+[[package]]
+name = "libc"
+version = "0.2.191"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65cd87c9a6d60536580b316ad985726104730a5151c99845f2490428ef91240a"
+
+[[package]]
+name = "memchr"
+version = "2.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.107"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "985e7ec9bb745e6ce6535b544d84d6cd6f7ad8bd711c398938ae983b91a766d9"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fbf4db142a473a8d80c26bbf18454ed458bf8d26c8219c331daecfdbd079001"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rand"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e058c7de0b26af77780c769414d6257830bb240f3c38477dbc2c16e5f54d6d4c"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.229"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4148590afebada386688f18773da617792bf2ef03ffc1e4cbd2b1d45b023e0ba"
+dependencies = [
+ "serde_core",
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_core"
+version = "1.0.229"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67dca2c9c51e58a4791a4b1ed58308b39c64224d349a935ab5039aa360942a48"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.229"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.9",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.154"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7e9cc8b1b85264074fbcc02a88680c4096b1e47df8f739dceb03bf482f04bd6"
+dependencies = [
+ "itoa",
+ "memchr",
+ "serde",
+ "serde_core",
+ "zmij",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.119"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "872831b642d1a07999a962a351ed35b955ea2cfc8f3862091e2a240a84f17297"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "syn"
+version = "3.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d78c8dee4c7bf0e14673097256fed6142ce9d3b85a408189d07482442145823b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2c754d6c33795a1c324727428e5a7dedb5b06195f9890bdbcba760d3e246563"
+
+[[package]]
+name = "wasi"
+version = "0.11.1+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
+
+[[package]]
+name = "zerocopy"
+version = "0.8.63"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5fe1f8f1b06191a00962174c61aa5005e0bb391a6d80d07e24d115c01a92ed8"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.63"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "863ad3ac83293fb4d740aedbfdc9240dd8d1a50c1099acd76ce80ce7c7230c7f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
+[[package]]
+name = "zmij"
+version = "1.0.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29666d0abbfad1e3dc4dcf6144730dd3a3ab225bbbdac83319345b1b44ccfc1b"
diff --git a/sandbox/Cargo.toml b/sandbox/Cargo.toml
new file mode 100644
index 0000000..67eac81
--- /dev/null
+++ b/sandbox/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "ci-sandbox"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+anyhow = "1"
+rand = "0.8"
+
+[dev-dependencies]
diff --git a/sandbox/src/lib.rs b/sandbox/src/lib.rs
new file mode 100644
index 0000000..f61e3ca
--- /dev/null
+++ b/sandbox/src/lib.rs
@@ -0,0 +1,49 @@
+//! Tiny crate used to exercise CI caching: enough deps to make a warm
+//! build obviously faster than a cold one.
+use anyhow::{bail, Result};
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Reading {
+    pub sensor: String,
+    pub celsius: f64,
+}
+
+pub fn to_fahrenheit(celsius: f64) -> f64 {
+    celsius * 9.0 / 5.0 + 32.0
+}
+
+pub fn parse(json: &str) -> Result<Reading> {
+    let r: Reading = serde_json::from_str(json)?;
+    if r.celsius < -273.15 {
+        bail!("{} C is below absolute zero", r.celsius);
+    }
+    Ok(r)
+}
+
+pub fn jitter(amount: f64) -> f64 {
+    use rand::Rng;
+    rand::thread_rng().gen_range(-amount..=amount)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn converts_units() {
+        assert!((to_fahrenheit(0.0) - 32.0).abs() < 1e-9);
+        assert!((to_fahrenheit(100.0) - 212.0).abs() < 1e-9);
+    }
+
+    #[test]
+    fn parses_reading() {
+        let r = parse(r#"{"sensor":"attic","celsius":21.5}"#).unwrap();
+        assert_eq!(r.sensor, "attic");
+    }
+
+    #[test]
+    fn rejects_impossible_temperature() {
+        assert!(parse(r#"{"sensor":"x","celsius":-300.0}"#).is_err());
+    }
+}