refactor web pagination and add partitioned events, flap/timeout showcase agents

deploy/showcase/agents/flap.toml

@@ -0,0 +1,25 @@
+hostname = "agent-flap"
+state_dir = "/var/lib/monlet-agent"
+
+[labels]
+scenario = "flapping"
+role = "showcase"
+
+[server]
+enabled = true
+url = "http://server:8000"
+token = "monlet-dev-token"
+heartbeat_interval = "5s"
+batch_interval = "3s"
+
+[metrics]
+enabled = false
+listen = "127.0.0.1:9465"
+
+[[checks]]
+id = "flap"
+name = "Flapping check (oscillates ok/critical)"
+command = "/opt/monlet/checks/flap.sh"
+interval = "10s"
+timeout = "3s"
+dedupe_key = "agent-flap:flap"

deploy/showcase/agents/timeout.toml

@@ -0,0 +1,33 @@
+hostname = "agent-timeout"
+state_dir = "/var/lib/monlet-agent"
+
+[labels]
+scenario = "timeout"
+role = "showcase"
+
+[server]
+enabled = true
+url = "http://server:8000"
+token = "monlet-dev-token"
+heartbeat_interval = "5s"
+batch_interval = "3s"
+
+[metrics]
+enabled = false
+listen = "127.0.0.1:9465"
+
+[[checks]]
+id = "ok_probe"
+name = "Healthy probe"
+command = "/opt/monlet/checks/exit_0.sh"
+interval = "10s"
+timeout = "3s"
+dedupe_key = "agent-timeout:ok_probe"
+
+[[checks]]
+id = "slow_probe"
+name = "Probe that exceeds the timeout"
+command = "/opt/monlet/checks/sleep_long.sh"
+interval = "10s"
+timeout = "2s"
+dedupe_key = "agent-timeout:slow_probe"

deploy/showcase/checks/flap.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+# Alternates between ok and critical every ~30 seconds to demonstrate flapping.
+slot=$(( $(date +%s) / 30 % 2 ))
+if [ "$slot" -eq 0 ]; then
+  echo "critical: flap window down"
+  exit 2
+fi
+echo "ok: flap window up"
+exit 0

deploy/showcase/checks/sleep_long.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+# Sleeps longer than the configured timeout to demonstrate timeout handling.
+sleep 30
+echo "should never reach here"
+exit 0