Add serverload endpoint (#1410)

* write usage script for cpu and free disk space tracking, testing new endpoint

* Test alias nginx path

* testing json

* fix server load json file being served by nginx

* Fix filenames

* Add changelog

* Add systemd file for serverload

* Update setup-scripts/serverload.sh

Co-authored-by: Peter-Jan Brone <peter-jan@settlemint.com>

.gitignore

@@ -96,3 +96,7 @@ docker/kratos/cr_certs/*.key
 # Oathkeeper JWKS signing token
 docker/kratos/oathkeeper/id_token.jwks.json
 /docker/kratos/config/kratos.yml
+
+# Setup-script log files
+/setup-scripts/serverload.log
+/setup-scripts/serverload.json

changelog/items/key-updates/serverload.md

@@ -0,0 +1 @@
+- Add `/serverload` endpoint for CPU usage and free disk space

docker/nginx/conf.d/server/server.api

@@ -71,6 +71,21 @@ location /skynet/stats {
     proxy_pass http://sia:9980/skynet/stats;
 }
 
+# Define path for server load endpoint
+location /serverload {
+    # Define root directory in the nginx container to load file from
+    root /usr/local/share;
+
+    # including this because of peer pressure from the other routes 
+    include /etc/nginx/conf.d/include/cors;
+
+    # tell nginx to expect json
+    default_type 'application/json';
+
+    # Allow for /serverload to load /serverload.json file
+    try_files $uri $uri.json =404;
+}
+
 location /skynet/health {
     include /etc/nginx/conf.d/include/cors;
 

setup-scripts/serverload.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Ensure serverload script is running to provide serverload stats.
+
+[Service]
+ExecStart=/bin/bash /home/user/skynet-webportal/serverload.sh
+
+[Install]
+WantedBy=multi-user.target

setup-scripts/serverload.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+: '
+This script writes the CPU usage and the free disk space to a file in a loop.
+The results are prepended to the file, so the most recent results are at the
+top.  This is so that the most recent information can easily be read from the
+top of the file and the file can easily be truncated if needed.
+
+This script is run by the serverload.service systemd process. The
+serverload.service file should be copied to
+/etc/systemd/system/serverload.service.
+
+The systemd process can then be started with the following commands:
+sudo systemctl start serverload.service
+
+The status of the process can be checked with:
+sudo systemctl is-active serverload.service
+'
+
+# Define Loop Interval
+loop_interval=60
+webportal_repo_setup_scripts="/home/user/skynet-webportal/setup-scripts"
+logfile_name="serverload.log"
+logfile=$webportal_repo_setup_scripts/$logfile_name
+jsonfile="serverload.json"
+nginx_docker_path="/usr/local/share"
+
+# Create logfile if it doesn't exist
+if [[ ! -e $logfile ]]; then
+    echo "init" > $logfile 
+fi
+
+# Write the output in an infinite loop.
+while true; do
+    # CPU usage
+    cpu=$(echo $[100-$(vmstat 1 2|tail -1|awk '{print $15}')]) 
+    sed -i "1iCPU: ${cpu}" $logfile
+
+    # Disk Usage
+    disk=$(df -Ph . | tail -1 | awk '{print $4}')
+    sed -i "1iDISK: ${disk}" $logfile
+    
+    # Write the timestamp
+    timestamp=$(date)
+    sed -i "1iTIMESTAMP: ${timestamp}" $logfile
+
+    # Write and copy a json file of the latest results to nginx docker container
+    # to serve
+    printf '{"cpu":"%s","disk":"%s","timestamp":"%s"}' "$cpu" "$disk" "$timestamp" > $webportal_repo_setup_scripts/$jsonfile
+    docker cp $webportal_repo_setup_scripts/$jsonfile nginx:$nginx_docker_path/$jsonfile
+
+    # Sleep
+    sleep $loop_interval
+done
+