From 9aa13e35ec4da546adc1b37bbaab8e0d2c654221 Mon Sep 17 00:00:00 2001
From: Ulric Qin <ulric.qin@gmail.com>
Date: Thu, 28 Apr 2022 10:14:49 +0800
Subject: [PATCH] add tomcat plugin framework

---
 agent/agent.go                |   1 +
 conf/input.tomcat/tomcat.toml |  29 +++++++++
 inputs/tomcat/tomcat.go       | 110 ++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 conf/input.tomcat/tomcat.toml
 create mode 100644 inputs/tomcat/tomcat.go

diff --git a/agent/agent.go b/agent/agent.go
index e26bad9..9733bdf 100644
--- a/agent/agent.go
+++ b/agent/agent.go
@@ -34,6 +34,7 @@ import (
 	_ "flashcat.cloud/categraf/inputs/procstat"
 	_ "flashcat.cloud/categraf/inputs/redis"
 	_ "flashcat.cloud/categraf/inputs/system"
+	_ "flashcat.cloud/categraf/inputs/tomcat"
 )
 
 type Agent struct {
diff --git a/conf/input.tomcat/tomcat.toml b/conf/input.tomcat/tomcat.toml
new file mode 100644
index 0000000..25ffd7c
--- /dev/null
+++ b/conf/input.tomcat/tomcat.toml
@@ -0,0 +1,29 @@
+# # collect interval
+# interval = 15
+
+# Gather metrics from the Tomcat server status page.
+[[instances]]
+## URL of the Tomcat server status
+# url = "http://127.0.0.1:8080/manager/status/all?XML=true"
+
+## HTTP Basic Auth Credentials
+# username = "tomcat"
+# password = "s3cret"
+
+## Request timeout
+# timeout = "5s"
+
+# # interval = global.interval * interval_times
+# interval_times = 1
+
+# important! use global unique string to specify instance
+# labels = { instance="192.168.1.2:8080", service="tomcat" }
+
+## Optional TLS Config
+# use_tls = false
+# tls_min_version = "1.2"
+# tls_ca = "/etc/categraf/ca.pem"
+# tls_cert = "/etc/categraf/cert.pem"
+# tls_key = "/etc/categraf/key.pem"
+## Use TLS but skip chain & host verification
+# insecure_skip_verify = true
diff --git a/inputs/tomcat/tomcat.go b/inputs/tomcat/tomcat.go
new file mode 100644
index 0000000..39242a5
--- /dev/null
+++ b/inputs/tomcat/tomcat.go
@@ -0,0 +1,110 @@
+package tomcat
+
+import (
+	"errors"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"flashcat.cloud/categraf/config"
+	"flashcat.cloud/categraf/inputs"
+	"flashcat.cloud/categraf/pkg/tls"
+	"flashcat.cloud/categraf/types"
+	"github.com/toolkits/pkg/container/list"
+)
+
+const inputName = "tomcat"
+
+type Instance struct {
+	URL           string            `toml:"url"`
+	Username      string            `toml:"username"`
+	Password      string            `toml:"password"`
+	Timeout       config.Duration   `toml:"timeout"`
+	Labels        map[string]string `toml:"labels"`
+	IntervalTimes int64             `toml:"interval_times"`
+
+	tls.ClientConfig
+}
+
+func (ins *Instance) Init() error {
+	if ins.URL == "" {
+		return errors.New("url is blank")
+	}
+
+	return nil
+}
+
+type Tomcat struct {
+	Interval  config.Duration `toml:"interval"`
+	Instances []*Instance     `toml:"instances"`
+
+	Counter uint64
+	wg      sync.WaitGroup
+}
+
+func init() {
+	inputs.Add(inputName, func() inputs.Input {
+		return &Tomcat{}
+	})
+}
+
+func (t *Tomcat) GetInputName() string {
+	return inputName
+}
+
+func (t *Tomcat) GetInterval() config.Duration {
+	return t.Interval
+}
+
+func (t *Tomcat) Init() error {
+	if len(t.Instances) == 0 {
+		return types.ErrInstancesEmpty
+	}
+
+	for i := 0; i < len(t.Instances); i++ {
+		if err := t.Instances[i].Init(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (t *Tomcat) Drop() {}
+
+func (t *Tomcat) Gather(slist *list.SafeList) {
+	atomic.AddUint64(&t.Counter, 1)
+	for i := range t.Instances {
+		ins := t.Instances[i]
+		t.wg.Add(1)
+		go t.gatherOnce(slist, ins)
+	}
+	t.wg.Wait()
+}
+
+func (t *Tomcat) gatherOnce(slist *list.SafeList, ins *Instance) {
+	defer t.wg.Done()
+
+	if ins.IntervalTimes > 0 {
+		counter := atomic.LoadUint64(&t.Counter)
+		if counter%uint64(ins.IntervalTimes) != 0 {
+			return
+		}
+	}
+
+	tags := map[string]string{"url": ins.URL}
+	for k, v := range ins.Labels {
+		tags[k] = v
+	}
+
+	begun := time.Now()
+
+	// scrape use seconds
+	defer func(begun time.Time) {
+		use := time.Since(begun).Seconds()
+		slist.PushFront(inputs.NewSample("scrape_use_seconds", use, tags))
+	}(begun)
+
+	// url cannot connect? up = 0
+
+}