Add reusable GitHub Action to install and cache nats server

[caspervonb]

Brings install time of nats-server from 2-3 minutes to 2-3 seconds.

[Copilot]

Pull Request Overview

This PR introduces a reusable GitHub Action to optimize NATS server installation in CI workflows, reducing installation time from 2-3 minutes to 2-3 seconds through caching.

• Replaces manual installation scripts with a centralized GitHub Action
• Implements caching strategy for NATS server binaries across workflow runs
• Simplifies workflow configuration by eliminating manual PATH management

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
.github/actions/setup-nats-server/action.yml	New composite action that downloads, caches, and configures NATS server
.github/workflows/test.yml	Updated to use the new action and simplified matrix configuration
nats/scripts/install_nats.sh	Removed obsolete installation script
nats/tests/utils.py	Updated comment to reference official NATS installation docs

---

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[Copilot]

[nitpick] Consider testing against multiple NATS versions to ensure compatibility. The original configuration tested against specific versions (v2.10.29, v2.11.8) and main branch, which provided better coverage for potential breaking changes.

Suggested change

	nats_version: ["latest"]
	nats_version: ["v2.10.29", "v2.11.8", "latest", "main"]

[Copilot]

Piping curl output directly to shell without verification poses a security risk. Consider downloading the script first, verifying its integrity, then executing it.

Suggested change

	curl -fsSL https://binaries.nats.dev/nats-io/nats-server/v2@${{ inputs.version }} | PREFIX="$INSTALL_DIR" sh
	INSTALL_SCRIPT="$(mktemp)"
	curl -fsSL https://binaries.nats.dev/nats-io/nats-server/v2@${{ inputs.version }} -o "$INSTALL_SCRIPT"
	# TODO: (Optional) Verify the integrity of $INSTALL_SCRIPT here (e.g., with sha256sum)
	PREFIX="$INSTALL_DIR" sh "$INSTALL_SCRIPT"
	rm -f "$INSTALL_SCRIPT"

[Copilot]

The Windows shim creation uses bash-specific syntax but may not work correctly on Windows runners. Consider using PowerShell or a more portable approach for Windows compatibility.

Suggested change

	# On Windows, create a shim without .exe extension
	if [ "$RUNNER_OS" = "Windows" ] && [ -f "$INSTALL_DIR/nats-server.exe" ]; then
	echo '#!/bin/bash' > "$INSTALL_DIR/nats-server"
	echo 'exec "$(dirname "$0")/nats-server.exe" "$@"' >> "$INSTALL_DIR/nats-server"
	chmod +x "$INSTALL_DIR/nats-server"
	# On Windows, create a shim without .exe extension using PowerShell
	if [ "$RUNNER_OS" = "Windows" ] && [ -f "$INSTALL_DIR/nats-server.exe" ]; then
	# Create a CMD shim for Windows
	echo '@echo off' > "$INSTALL_DIR/nats-server.cmd"
	echo 'set SCRIPT_DIR=%~dp0' >> "$INSTALL_DIR/nats-server.cmd"
	echo '"%SCRIPT_DIR%nats-server.exe" %*' >> "$INSTALL_DIR/nats-server.cmd"