update health-client to v4 API

CHANGELOG.md

@@ -26,6 +26,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - [#7063](https://github.com/apache/trafficcontrol/pull/7063) *Traffic Ops* Python client now uses Traffic Ops API 4.1 by default.
 - [#6981](https://github.com/apache/trafficcontrol/pull/6981) *Traffic Portal* Obscures sensitive text in Delivery Service "Raw Remap" fields, private SSL keys, "Header Rewrite" rules, and ILO interface passwords by default.
 - [#7037](https://github.com/apache/trafficcontrol/pull/7037) *Traffic Router* Uses Traffic Ops API 4.0 by default
+- [#7191](https://github.com/apache/trafficcontrol/issues/7191) *tc-health-client* Uses Traffic Ops API 4.0. Also added reload option to systemd service file
 
 ### Fixed
 - [#7179](https://github.com/apache/trafficcontrol/issues/7179) *Traffic Portal* Fixed search filter for Delivery Service Table

tc-health-client/README.md

@@ -56,9 +56,10 @@ otherwise unavailable, the tc-health-client will utilize the **Traffic Server**
 and **Traffic Monitor** has determined that the marked down host is now available, 
 the client will then utilize the **Traffic Server** tool to mark the host back up.
 
-Also on each polling cycle the configuration file, **tc-health-client.json** is 
-checked and a new config is reloaded if the file has changed since the last 
-polling cycle.  The **Traffic Monitors** list is refreshed from **Traffic Ops**.
+Any changes to **tc-health-client.json** will require sending a SIGHUP to the running
+process. This will cause the tc-health-client to read the config file and load any
+changes, the **Traffic Monitors** list will be refreshed from **Traffic Ops**.
+**systemctl reload tc-health-client** can also be used to send a SIGHUP.  
 
 If errors are encountered while polling a Traffic Monitor, the error is logged
 and the **Traffic Monitors** list is refreshed from **Traffic Ops**.

tc-health-client/tc-health-client.service

@@ -23,6 +23,7 @@ Requires=trafficserver.service
 
 [Service]
 ExecStart=/usr/bin/tc-health-client -vv
+ExecReload=/bin/kill -HUP $MAINPID
 Restart=always
 RestartSec=5
 PIDFile=/run/tc-health-client.pid

tc-health-client/tmagent/tmagent.go

@@ -38,7 +38,7 @@ import (
 	"github.com/apache/trafficcontrol/lib/go-tc"
 	"github.com/apache/trafficcontrol/tc-health-client/config"
 	"github.com/apache/trafficcontrol/tc-health-client/util"
-	toclient "github.com/apache/trafficcontrol/traffic_ops/v3-client"
+	toclient "github.com/apache/trafficcontrol/traffic_ops/v4-client"
 
 	"gopkg.in/yaml.v2"
 )
@@ -636,7 +636,7 @@ func (pi *ParentInfo) GetTOData(cfg *config.Cfg) error {
 		}
 	}
 
-	srvs, _, err := toData.TOClient.GetServersWithHdr(nil, nil)
+	srvs, _, err := toData.TOClient.GetServers(toclient.NewRequestOptions())
 	if err != nil {
 		// next time we'll login again and get a new session.
 		toData.TOClient = nil