Add non-nix installation instructions (#765)

* Add non-nix installation instructions
* Enable building on PR to create workflow

.github/workflows/ubuntu-install-without-nix.yml

@@ -0,0 +1,27 @@
+name: Ubuntu install without nix
+
+on:
+  schedule:
+    - cron: "0 0 * * MON"
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install and test
+        # Execute all lines that start with four spaces, and remove leading 'sudo '
+        # because we're in a container and already root.
+        run: |
+          grep '^    ' doc/ubuntu.md \
+            | sed 's/^    //' \
+            | sed 's/^sudo //' \
+            | bash -exo pipefail

README.md

@@ -19,6 +19,7 @@ a dockerized Espresso Sequencer network with an example Layer 2 rollup applicati
 - Obtain code: `git clone [email protected]:EspressoSystems/espresso-sequencer`.
 - Make sure [nix](https://nixos.org/download.html) is installed.
 - Activate the environment with `nix-shell`, or `nix develop`, or `direnv allow` if using [direnv](https://direnv.net/).
+- For installation without nix please see [ubuntu.md](./doc/ubuntu.md).
 
 ## Run the tests
 

doc/ubuntu.md

@@ -0,0 +1,36 @@
+# Installing on ubuntu (without nix)
+
+<!-- Note that all lines that start with four spaces will be executed in the CI -->
+
+## Install system dependencies
+
+    sudo apt-get update
+    sudo apt-get install -y curl cmake pkg-config libssl-dev protobuf-compiler git
+
+## Install rustup
+
+    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+    source $HOME/.cargo/env
+
+## Install foundry
+
+    curl --proto '=https' --tlsv1.2 -sSf -L https://foundry.paradigm.xyz | bash
+    source $HOME/.bashrc
+    foundryup
+
+## Clone the repository
+
+    git clone https://github.com/EspressoSystems/espresso-sequencer/
+    cd espresso-sequencer
+
+## Run the rust tests
+
+    export RUSTFLAGS='--cfg async_executor_impl="async-std" --cfg async_channel_impl="async-std"'
+    cargo test --release
+
+## Run the foundry tests
+
+    cargo build --release --bin diff-test
+    export PATH=$PWD/target/release:$PATH
+    forge test -v
+

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "1.73.0"
+components = [ "rustfmt", "llvm-tools-preview", "rust-src", "clippy" ]
+profile = "minimal"