feat: Add support for Prometheus AlertManager (#89)

* feat: Add support for Prometheus AlertManager in `alertmanager`

* chore: Add default value for CurioAlertingConfig

* chore: make the payload label key lowercase && add source to the labels

* fix: Add default time for AlertPayload

* update doc

alertmanager/doc.go

@@ -0,0 +1,41 @@
+/*
+Package alertmanager provides a framework for monitoring and alerting within the Curio project. It supports dynamic plugin integration for alert notifications, allowing for flexible and extensible alerting mechanisms.
+
+Implementing a New Plugin:
+
+1. Define a struct that implements the Plugin interface, which includes the SendAlert method for dispatching alerts.
+2. Implement the SendAlert method to handle the alert logic specific to your plugin.
+3. Provide a constructor function for your plugin to facilitate its configuration and initialization.
+4. Register your plugin in the LoadAlertPlugins function, which dynamically loads plugins based on the CurioAlertingConfig.
+
+Plugin Configuration:
+
+Plugins are configured through the config.CurioAlertingConfig struct. Each plugin can have its own configuration section within this struct, enabling or disabling the plugin and setting plugin-specific parameters.
+
+Example:
+
+```go
+type MyPlugin struct{}
+
+	func (p *MyPlugin) SendAlert(data *plugin.AlertPayload) error {
+		// Plugin-specific alert sending logic
+		return nil
+	}
+
+	func NewMyPlugin() *MyPlugin {
+		return &MyPlugin{}
+	}
+
+	func LoadAlertPlugins(cfg config.CurioAlertingConfig) []plugin.Plugin {
+		var plugins []plugin.Plugin
+		if cfg.MyPlugin.Enabled {
+			plugins = append(plugins, NewMyPlugin())
+		}
+		return plugins
+	}
+
+```
+This package leverages the CurioAlertingConfig for plugin configuration,
+enabling a modular approach to adding or removing alerting capabilities as required.
+*/
+package alertmanager

alertmanager/plugin/pager_duty.go

@@ -0,0 +1,111 @@
+package plugin
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/curio/deps/config"
+	"github.com/samber/lo"
+)
+
+type PagerDuty struct {
+	cfg config.PagerDutyConfig
+}
+
+func NewPagerDuty(cfg config.PagerDutyConfig) Plugin {
+	return &PagerDuty{
+		cfg: cfg,
+	}
+}
+
+// SendAlert sends an alert to PagerDuty with the provided payload data.
+// It creates a PDData struct with the provided routing key, event action and payload.
+// It creates an HTTP POST request with the PagerDuty event URL as the endpoint and the marshaled JSON data as the request body.
+// It sends the request using an HTTP client with a maximum of 5 retries for network errors with exponential backoff before each retry.
+// It handles different HTTP response status codes and returns an error based on the status code().
+// If all retries fail, it returns an error indicating the last network error encountered.
+func (p *PagerDuty) SendAlert(data *AlertPayload) error {
+
+	type pdPayload struct {
+		Summary       string      `json:"summary"`
+		Severity      string      `json:"severity"`
+		Source        string      `json:"source"`
+		Component     string      `json:"component,omitempty"`
+		Group         string      `json:"group,omitempty"`
+		Class         string      `json:"class,omitempty"`
+		CustomDetails interface{} `json:"custom_details,omitempty"`
+	}
+
+	type pdData struct {
+		RoutingKey  string     `json:"routing_key"`
+		EventAction string     `json:"event_action"`
+		Payload     *pdPayload `json:"payload"`
+	}
+
+	payload := &pdData{
+		RoutingKey:  p.cfg.PageDutyIntegrationKey,
+		EventAction: "trigger",
+		Payload: &pdPayload{
+			Summary:       data.Summary,
+			Severity:      data.Severity,
+			Source:        data.Source,
+			CustomDetails: data.Details,
+		},
+	}
+
+	jsonData, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("error marshaling JSON: %w", err)
+	}
+
+	req, err := http.NewRequest("POST", p.cfg.PagerDutyEventURL, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return fmt.Errorf("error creating request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	client := &http.Client{
+		Timeout: time.Second * 15,
+	}
+	iter, _, err := lo.AttemptWithDelay(5, time.Second,
+		func(index int, duration time.Duration) error {
+			resp, err := client.Do(req)
+			if err != nil {
+				time.Sleep(time.Duration(2*index) * duration) // Exponential backoff
+				return err
+			}
+			defer func() { _ = resp.Body.Close() }()
+
+			switch resp.StatusCode {
+			case 202:
+				log.Debug("Accepted: The event has been accepted by PagerDuty.")
+				return nil
+			case 400:
+				bd, rerr := io.ReadAll(resp.Body)
+				if rerr != nil {
+					return xerrors.Errorf("Bad request: payload JSON is invalid. Failed to read the body: %w", err)
+				}
+				return xerrors.Errorf("Bad request: payload JSON is invalid %s", string(bd))
+			case 429:
+				log.Debug("Too many API calls, retrying after backoff...")
+				time.Sleep(time.Duration(5*index) * time.Second) // Exponential backoff
+			case 500, 501, 502, 503, 504:
+				log.Debug("Server error, retrying after backoff...")
+				time.Sleep(time.Duration(5*index) * time.Second) // Exponential backoff
+			default:
+				log.Errorw("Response status:", resp.Status)
+				return xerrors.Errorf("Unexpected HTTP response: %s", resp.Status)
+			}
+			return nil
+		})
+	if err != nil {
+		return fmt.Errorf("after %d retries,last error: %w", iter, err)
+	}
+	return nil
+}

alertmanager/plugin/plugin.go

@@ -0,0 +1,34 @@
+package plugin
+
+import (
+	"time"
+
+	"github.com/filecoin-project/curio/deps/config"
+
+	logging "github.com/ipfs/go-log/v2"
+)
+
+var log = logging.Logger("curio/alertplugins")
+
+type Plugin interface {
+	SendAlert(data *AlertPayload) error
+}
+
+type AlertPayload struct {
+	Summary  string
+	Severity string
+	Source   string
+	Details  map[string]interface{}
+	Time     time.Time
+}
+
+func LoadAlertPlugins(cfg config.CurioAlertingConfig) []Plugin {
+	var plugins []Plugin
+	if cfg.PagerDuty.Enable {
+		plugins = append(plugins, NewPagerDuty(cfg.PagerDuty))
+	}
+	if cfg.PrometheusAlertManager.Enable {
+		plugins = append(plugins, NewPrometheusAlertManager(cfg.PrometheusAlertManager))
+	}
+	return plugins
+}

alertmanager/plugin/prometheus_alertmanager.go

@@ -0,0 +1,99 @@
+package plugin
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/filecoin-project/curio/deps/config"
+	"github.com/samber/lo"
+)
+
+type PrometheusAlertManager struct {
+	cfg config.PrometheusAlertManagerConfig
+}
+
+func NewPrometheusAlertManager(cfg config.PrometheusAlertManagerConfig) Plugin {
+	return &PrometheusAlertManager{
+		cfg: cfg,
+	}
+}
+
+// SendAlert sends an alert to Prometheus AlertManager with the provided payload data.
+// API reference: https://raw.githubusercontent.com/prometheus/alertmanager/main/api/v2/openapi.yaml
+func (p *PrometheusAlertManager) SendAlert(data *AlertPayload) error {
+	if len(data.Details) == 0 {
+		return nil
+	}
+
+	type amPayload struct {
+		StartsAt    time.Time              `json:"startsAt"`
+		EndsAt      *time.Time             `json:"EndsAt,omitempty"`
+		Annotations map[string]interface{} `json:"annotations"`
+		Labels      map[string]string      `json:"labels"`
+
+		// is a unique back-link which identifies the causing entity of this alert
+		//GeneratorURL string            `json:"generatorURL"`
+	}
+
+	var alerts []*amPayload
+	for k, v := range data.Details {
+		alerts = append(alerts, &amPayload{
+			StartsAt: data.Time,
+			Labels: map[string]string{
+				"alertName": k,
+				"severity":  data.Severity,
+				"instance":  data.Source,
+			},
+			Annotations: map[string]interface{}{
+				"summary": data.Summary,
+				"details": v,
+			},
+		})
+	}
+
+	jsonData, err := json.Marshal(alerts)
+	if err != nil {
+		return fmt.Errorf("error marshaling JSON: %w", err)
+	}
+	req, err := http.NewRequest("POST", p.cfg.AlertManagerURL, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return fmt.Errorf("error creating request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	client := &http.Client{
+		Timeout: time.Second * 15,
+	}
+	iter, _, err := lo.AttemptWithDelay(5, time.Second,
+		func(index int, duration time.Duration) error {
+			resp, err := client.Do(req)
+			if err != nil {
+				time.Sleep(time.Duration(2*index) * duration) // Exponential backoff
+				return err
+			}
+			defer func() { _ = resp.Body.Close() }()
+
+			switch resp.StatusCode {
+			case http.StatusOK:
+				return nil
+			case http.StatusBadRequest, http.StatusInternalServerError:
+				errBody, err := io.ReadAll(resp.Body)
+				if err != nil {
+					time.Sleep(time.Duration(2*index) * duration) // Exponential backoff
+					return err
+				}
+				return fmt.Errorf("error: %s", string(errBody))
+			default:
+				time.Sleep(time.Duration(2*index) * duration) // Exponential backoff
+				return fmt.Errorf("unexpected HTTP response: %s", resp.Status)
+			}
+		})
+	if err != nil {
+		return fmt.Errorf("after %d retries,last error: %w", iter, err)
+	}
+	return nil
+}