Use scrape manager (#6)

.golangci.yml

@@ -19,7 +19,6 @@ linters:
   disable-all: true
   enable:
     - bodyclose
-    - errcheck
     - gocritic
     - gofmt
     - goimports

go.mod

@@ -3,6 +3,8 @@ module github.com/mattermost/mattermost-plugin-metrics
 go 1.20
 
 require (
+	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137
+	github.com/go-kit/log v0.2.1
 	github.com/mattermost/mattermost/server/public v0.0.9
 	github.com/mattermost/mattermost/server/v8 v8.0.0-20231109142113-8bf0c1971415
 	github.com/pkg/errors v0.9.1
@@ -18,7 +20,6 @@ require (
 	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.3.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.3.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.0.0 // indirect
-	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
 	github.com/aws/aws-sdk-go v1.44.302 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/blang/semver/v4 v4.0.0 // indirect
@@ -30,7 +31,6 @@ require (
 	github.com/fatih/color v1.15.0 // indirect
 	github.com/francoispqt/gojay v1.2.13 // indirect
 	github.com/go-asn1-ber/asn1-ber v1.5.4 // indirect
-	github.com/go-kit/log v0.2.1 // indirect
 	github.com/go-logfmt/logfmt v0.6.0 // indirect
 	github.com/go-sql-driver/mysql v1.7.1 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect

server/configuration.go

@@ -3,11 +3,16 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"net"
 	"path/filepath"
 	"reflect"
 
-	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/alecthomas/units"
 	"github.com/pkg/errors"
+	promModel "github.com/prometheus/common/model"
+	"github.com/prometheus/prometheus/discovery/targetgroup"
+
+	"github.com/mattermost/mattermost/server/public/model"
 )
 
 // configuration captures the plugin's external configuration as exposed in the Mattermost server
@@ -51,7 +56,7 @@ func (c *configuration) SetDefaults() {
 		c.EnableMemorySnapshotOnShutdown = model.NewBool(true)
 	}
 	if c.BodySizeLimitBytes == nil {
-		c.BodySizeLimitBytes = model.NewInt64(10000000)
+		c.BodySizeLimitBytes = model.NewInt64(int64(units.GiB))
 	}
 	if c.SampleLimit == nil {
 		c.SampleLimit = model.NewInt(0)
@@ -101,26 +106,6 @@ func (c *configuration) Clone() (*configuration, error) {
 	return &clone, nil
 }
 
-// getConfiguration retrieves the active configuration under lock, making it safe to use
-// concurrently. The active configuration may change underneath the client of this method, but
-// the struct returned by this API call is considered immutable.
-func (p *Plugin) getConfiguration() (*configuration, error) {
-	p.configurationLock.Lock()
-	defer p.configurationLock.Unlock()
-
-	if p.configuration == nil {
-		p.configuration = new(configuration)
-		p.configuration.SetDefaults()
-	}
-
-	return p.configuration.Clone()
-}
-
-// func (p *Plugin) saveConfiguration() error {
-// 	p.API.SavePluginConfig()
-// 	return nil
-// }
-
 // setConfiguration replaces the active configuration under lock.
 //
 // Do not call setConfiguration while holding the configurationLock, as sync.Mutex is not
@@ -222,3 +207,43 @@ func (p *Plugin) isHA() bool {
 
 	return cfg.ClusterSettings.Enable != nil && *cfg.ClusterSettings.Enable
 }
+
+func generateTargetGroup(appCfg *model.Config, nodes []*model.ClusterDiscovery) (map[string][]*targetgroup.Group, error) {
+	host, port, err := net.SplitHostPort(*appCfg.MetricsSettings.ListenAddress)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse the listen address %q", *appCfg.MetricsSettings.ListenAddress)
+	}
+
+	sync := make(map[string][]*targetgroup.Group)
+
+	if nodes == nil || len(nodes) < 2 {
+		if host == "" {
+			host = "localhost"
+		}
+		sync["prometheus"] = []*targetgroup.Group{
+			{
+				Targets: []promModel.LabelSet{
+					{
+						promModel.AddressLabel: promModel.LabelValue(net.JoinHostPort(host, port)),
+					},
+				},
+			},
+		}
+
+		return sync, nil
+	}
+
+	targets := make([]promModel.LabelSet, len(nodes))
+	for i, node := range nodes {
+		targets[i] = promModel.LabelSet{
+			promModel.AddressLabel: promModel.LabelValue(net.JoinHostPort(node.Hostname, port)),
+		}
+	}
+	sync["prometheus"] = []*targetgroup.Group{
+		{
+			Targets: targets,
+		},
+	}
+
+	return sync, nil
+}

server/const.go

@@ -1,9 +1,5 @@
 package main
 
-import (
-	"github.com/prometheus/prometheus/model/labels"
-)
-
-var (
-	sampleMutator func(labels.Labels) labels.Labels //nolint:unused
+const (
+	PluginName = "mattermost-plugin-metrics"
 )

server/log_test.go

@@ -3,9 +3,10 @@ package main
 import (
 	"testing"
 
-	"github.com/mattermost/mattermost-plugin-metrics/server/mocks"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/mock/gomock"
+
+	"github.com/mattermost/mattermost-plugin-metrics/server/mocks"
 )
 
 func TestLog(t *testing.T) {