README.md

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+# PiDP 10 Services
+
+## Overview
+
+This repository combines a set of useful scripts and services, to run on the
+PiDP-10 in order to make it easier to work with it and develop for it. These
+services can be installed on the PiDP-10 and automate tasks such as copying
+files onto the ITS operating system. These tools help automate processes, that
+would require interaction with the Linux part of the PiDP-10 when developing on
+another system.
+
+## git-monitor
+
+The git-monitor is a system service that monitors a target directory on the
+PiDP-10. It contains a file with a list of git repositories to monitor, one at a
+time. The service will check if any of the repositories changed, and pull them.
+After a successful pull a script will be called, if it exists, that allows the
+newly updated repository to interact with a running PDP-10 simulation.
+
+The monitor consists of a script, that needs to be installed to `/usr/local/bin`
+and a systemd unit-file to run it as a service.
+
+### Installation
+
+To install the git-monitor, clone this repository to the target computer, and
+run the install script:
+
+```bash
+git clone https://gitea.orca-central.de/jali/PiDP10Services.git
+sudo ./install.sh
+```
+
+This will install the service on your system and start it. If you want the
+service to be enabled on system boot, enable the service:
+
+```bash
+sudo systemctl enable git-monitor.service
+```
+
+### Configuration
+
+The service is usable immediately after installation. The service is configured
+through a series of environment variables, that can be set to change the default
+behaviour. There are five different environment variables to configure the
+service with:
+
+<table>
+  <tr>
+    <th>Environment Variable</th>
+    <th>Description</th>
+    <th>Default Value</th>
+  </tr>
+  <tr>
+    <td>GITMONITOR_URLS</td>
+    <td>A file that contains the list of observed repositories in a directory by name and URL.</td>
+    <td>/opt/src/repository.list</td>
+  </tr>
+  <tr>
+    <td>GITMONITOR_LOCAL_PATH</td>
+    <td>The path in which the clone repositories will be stored.</td>
+    <td>/opt/src</td>
+  </tr>
+  <tr>
+    <td>GITMONITOR_BRANCH_NAME</td>
+    <td>The name of the branch to observe.</td>
+    <td>develop</td>
+  </tr>
+  <tr>
+    <td>GITMONITOR_POLL_INTERVALL</td>
+    <td>The number of seconds to wait until the next poll.</td>
+    <td>30</td>
+  </tr>
+  <tr>
+    <td>GITMONITOR_LOCK_FILE</td>
+    <td>The lock file that is used to monitor the service. </td>
+    <td>/run/lock/git-monitor.lock</td>
+  </tr>
+</table>
+
+You can override these settings by creating an override file for the service
+unit. Create a new file
+`/etc/serviced/service/git-monitor.service.d/override.conf` by typing
+`sudo systemctl edit git-monitor.service`. You can then uncomment the
+`Environment` statements, and change the value of the variables accordingly.

install.sh

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+#!/bin/sh
+# Install the service on the target machine
+
+SERVICEDIR="/usr/local/bin"
+SYSTEMDDIR="/etc/systemd/system"
+
+echo "- Installing the service files"
+cp ./services/git-monitor $SERVICEDIR
+cp ./units/git-monitor.service $SYSTEMDDIR
+
+echo "- Preparing the service files"
+systemctl daemon-reload
+systemctl start git-monitor.service
+
+echo "- Installation complete."

services/git-monitor

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+#!/bin/bash
+
+# Configuration
+[[ "x${GITMONITOR_URLS}" == "x" ]] && GITMONITOR_URLS="/opt/src/repository.list"
+[[ "x${GITMONITOR_LOCAL_PATH}" == "x" ]] && GITMONITOR_LOCAL_PATH="/opt/src"
+[[ "x${GITMONITOR_BRANCH_NAME}" == "x" ]] && GITMONITOR_BRANCH_NAME="develop"
+[[ "x${GITMONITOR_POLL_INTERVAL}" == "x" ]] && GITMONITOR_POLL_INTERVAL=60  # Seconds between checks
+[[ "x${GITMONITOR_LOCK_FILE}" == "x" ]] && GITMONITOR_LOCK_FILE="/run/lock/git-monitor.lock" # File to prevent multiple instances
+
+IFS="|"
+
+# Functions
+log_message() {
+  local level=$1
+  local message=$2
+  timestamp=$(date +'%Y-%m-%d %H:%M:%S')
+  #echo "$timestamp [$level] $message" >> "$LOG_FILE"
+  echo "$timestamp [$level] $message"  # Also print to console (optional)
+}
+
+check_lock() {
+  if [ -f "$GITMONITOR_LOCK_FILE" ]; then
+    log_message "WARN" "Another instance is already running. Exiting."
+    exit 1
+  fi
+}
+
+create_lock() {
+  touch "$GITMONITOR_LOCK_FILE"
+}
+
+run_after() {
+  local after_pull_script=$1
+  source $after_pull_script
+}
+
+initialize_repos() {
+  while read -r repo_name repo_url; do
+    if [ ! -d "$GITMONITOR_LOCAL_PATH/$repo_name" ]; then
+      log_message "INFO" "Repository directory $GITMONITO_LOCAL_PATH/$repo_name does not exist. Cloning..."
+      mkdir -p "$GITMONITOR_LOCAL_PATH/$repo_name"
+      git clone --depth 1 "$repo_url" "$GITMONITOR_LOCAL_PATH/$repo_name"
+      if [ $? -ne 0 ]; then
+        log_message "ERROR" "Failed to clone repository. Exiting."
+        exit 1
+      fi
+      log_message "INFO" "Repository cloned successfully."
+    fi
+  done <$GITMONITOR_URLS
+}
+
+check_for_updates() {
+  local repo_name=$1
+  local last_commit_hash
+  local current_commit_hash
+
+  # Get the last known commit hash (from a file)
+  cd "$GITMONITOR
+_LOCAL_PATH/$repo_name"
+  if [ -f "$GITMONITOR_LOCAL_PATH/$repo_name/.git-monitor-last-commit" ]; then
+    last_commit_hash=$(cat "$GITMONITOR_LOCAL_PATH/$repo_name/.git-monitor-last-commit")
+  else
+    last_commit_hash="" # Initialize if file doesn't exist
+  fi
+
+  # Fetch the latest commit hash from the remote repository
+  git -C "$GITMONITOR_LOCAL_PATH/$repo_name" fetch origin $GITMONITOR_BRANCH_NAME
+  current_commit_hash=$(git -C "$GITMONITOR_LOCAL_PATH/$repo_name" rev-parse origin $GITMONITOR_BRANCH_NAME)
+
+  if [ -z "$last_commit_hash" ] || [ "$current_commit_hash" != "$last_commit_hash" ]; then
+    log_message "INFO" "New commits detected. Pulling..."
+    git -C "$GITMONITOR
+  _LOCAL_PATH/$repo_name" pull origin $GITMONITOR_BRANCH_NAME
+    if [ $? -eq 0 ]; then
+      log_message "INFO" "Pull successful."
+
+      # run local scripts
+      if [ -f "$GITMONITOR_LOCAL_PATH/$repo_name/.git-monitor_after.sh" ]; then
+        run_after "$GITMONITOR_LOCAL_PATH/$repo_name/.git-monitor_after.sh"
+      fi
+    
+      # Update the last commit hash file
+      echo "$current_commit_hash" > "$GITMONITOR_LOCAL_PATH/$repo_name/.git-monitor-last-commit"
+    else
+      log_message "ERROR" "Pull failed."
+    fi
+  fi
+}
+
+# Main Execution
+
+trap 'rm -f $GITMONITOR_LOCK_FILE' EXIT
+
+check_lock
+create_lock
+
+log_message "INFO" "Git monitor started."
+
+initialize_repos
+
+while true; do
+  while read -r repo_name repo_url; do
+    check_for_updates $repo_name
+  done < $GITMONITOR_URLS
+  sleep "$GITMONITOR_POLL_INTERVAL"
+done
+

units/git-monitor.service

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+[Unit]
+Description=Get Repository Monitor
+After=network.target
+
+[Service]
+ExecStart=/usr/local/bin/git-monitor
+Restart=on-failure
+User=monitor
+WorkingDirectory=/opt/src
+Environment="GITMONITOR_URLS=/opt/src/repository.list"
+Environment="GITMONITOR_LOCAL_PATH=/opt/src"
+Environment="GITMONITOR_BRANCH_NAME=develop"
+Environment="GITMONITOR_POLL_INTERVALL=30"
+Environment="GITMONITOR_LOCK_FILE=/run/lock/git-monitor.lock"
+
+[Install]
+WantedBy=multi-user.target