pping: Add systemd unit files for running pping

Add some example files for setting up ePPing with systemd.
The setup creates "log" files in /var/log/pping and rotates
them every minute (appending a date at the time of rotation).

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>

pping/scripts/rotate-pping-output.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+MAX_WAIT_ITER=10
+pping_path=${1:-"/var/log/pping/pping.out.json"}
+
+pping_folder=$(dirname "$pping_path")
+pping_file=$(basename "$pping_path")
+
+if [[ ! -f "$pping_path" ]]; then
+    # Nothing to rotate
+    exit 0
+fi
+
+dailyfolder="$pping_folder/$(date -Idate)"
+if ! mkdir -p "$dailyfolder"; then
+    exit 1
+fi
+
+newplace="$dailyfolder/$pping_file.$(date -Iseconds)"
+if ! mv "$pping_path" "$newplace"; then
+    exit 1
+fi
+
+# Tell ePPing to reopen file
+if systemctl is-active --quiet pping.service; then
+    systemctl reload pping.service
+fi
+
+if [[ -f "$newplace" ]]; then
+    for (( i = 0; i < MAX_WAIT_ITER; i++)); do
+	if fuser -s "$newplace"; then
+	    sleep 1
+	else
+	    gzip "$newplace"
+	    exit $?
+	fi
+    done
+fi
+
+echo "Timed out waiting for $newplace to become unused, unable to compress it" 1>&2
+exit 1

pping/systemd-files/pping.service

@@ -0,0 +1,32 @@
+[Unit]
+Description=ePPing - Passive monitoring of network RTTs
+After=network.service
+Wants=rotate-pping.timer
+
+# Uncomment below if running with LibreQoS
+# After=lqosd.service
+
+[Service]
+# Ensure folder for saving output to exists
+ExecStartPre=/usr/bin/mkdir -p /var/log/pping
+
+# Rotate any old output first to ensure ePPing can start writing to its intended file
+ExecStartPre=/opt/bpf-examples/pping/scripts/rotate-pping-output.sh /var/log/pping/pping.out.json
+
+WorkingDirectory=/opt/bpf-examples/pping
+ExecStart=/opt/bpf-examples/pping/pping -i <interface> -l -r 10 -a 10 -F json -w /var/log/pping/pping.out.json
+
+# On systemctl reload, send a SIGHUP to ePPing which causes it to reopen its output file
+ExecReload=kill -HUP $MAINPID
+
+Restart=on-failure
+RestartSec=60
+
+# Set to whatever maximum memory footprint you can tolerate
+# Note, hard-kills the ePPing process without allowing it to clean up. Consider
+# running /scripts/cleanup-tc-progs after.
+MemoryMax=4G
+
+[Install]
+WantedBy=default.target
+

pping/systemd-files/rotate-pping.service

@@ -0,0 +1,6 @@
+[Unit]
+Description=Rotates the output file from ePPing (pping.service)
+
+[Service]
+Type=oneshot
+ExecStart=/opt/bpf-examples/pping/scripts/rotate-pping-output.sh /var/log/pping/pping.out.json

pping/systemd-files/rotate-pping.timer

@@ -0,0 +1,11 @@
+[Unit]
+Description=Rotate ePPing output periodically
+PartOf=pping.service
+
+[Timer]
+Unit=rotate-pping.service
+
+# Rotate ePPing output every X seconds
+OnActiveSec=60
+OnUnitActiveSec=60
+AccuracySec=1us