From 285f480c01306b9cc7a4fb94dcc60dd83fd88a13 Mon Sep 17 00:00:00 2001
From: futuarmo <armen114@yandex.ru>
Date: Thu, 28 Apr 2022 13:40:08 +0300
Subject: [PATCH] Cluster configuration support (#130)
* Add several hosts separated by ;
* Reconnect on host change
* Issue #130: fix error
---
backend/datasource.go | 84 ++++++++++++++++++++++++++-----------------
backend/plugin.go | 13 +------
2 files changed, 52 insertions(+), 45 deletions(-)
diff --git a/backend/datasource.go b/backend/datasource.go
index 4e689fb..6e21733 100644
--- a/backend/datasource.go
+++ b/backend/datasource.go
@@ -5,6 +5,7 @@ import (
"errors"
"fmt"
"net/http"
+ "strings"
"strconv"
"time"
@@ -23,7 +24,6 @@ type CassandraDatasource struct {
resourceHandler backend.CallResourceHandler
builder *QueryBuilder
processor *QueryProcessor
- sessions map[int]*gocql.Session
session *gocql.Session
}
@@ -43,7 +43,7 @@ func NewDataSource() *CassandraDatasource {
}
func (ds *CassandraDatasource) handleKeyspaces(rw http.ResponseWriter, req *http.Request) {
- ds.logger.Info("Process 'keyspaces' request")
+ ds.logger.Debug("Process 'keyspaces' request")
ctx := httpadapter.PluginConfigFromContext(req.Context())
@@ -59,7 +59,7 @@ func (ds *CassandraDatasource) handleKeyspaces(rw http.ResponseWriter, req *http
}
func (ds *CassandraDatasource) handleTables(rw http.ResponseWriter, req *http.Request) {
- ds.logger.Info("Process 'tables' request")
+ ds.logger.Debug("Process 'tables' request")
ctx := httpadapter.PluginConfigFromContext(req.Context())
@@ -127,10 +127,10 @@ func (ds *CassandraDatasource) HandleMetricQueries(ctx context.Context, req *bac
}
func (ds *CassandraDatasource) handleMetricQuery(ctx *backend.PluginContext, query backend.DataQuery) backend.DataResponse {
- _, err := ds.connect(ctx)
+ err := ds.connectIfNeeded(ctx)
if err != nil {
ds.logger.Warn("Failed to connect", "Message", err)
- return dataResponse(data.Frames{}, fmt.Errorf("Failed to connect to server, please inspect Grafana server log for details"))
+ return dataResponse(data.Frames{}, errors.New("Failed to connect to server, please inspect Grafana server log for details"))
}
frames, err := ds.metricQuery(&query)
@@ -139,7 +139,7 @@ func (ds *CassandraDatasource) handleMetricQuery(ctx *backend.PluginContext, que
}
func (ds *CassandraDatasource) getConnected(ctx *backend.PluginContext, getData func() ([]string, error)) ([]string, error) {
- _, err := ds.connect(ctx)
+ err := ds.connectIfNeeded(ctx)
if err != nil {
ds.logger.Warn("Failed to connect", "Message", err)
@@ -223,14 +223,21 @@ func (ds *CassandraDatasource) getKeyspaces(ctx *backend.PluginContext) ([]strin
return ds.getConnected(ctx, getKeyspaces)
}
-func (ds *CassandraDatasource) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) error {
- _, err := ds.connect(&req.PluginContext)
+func (ds *CassandraDatasource) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
+ err := ds.connect(&req.PluginContext)
if err != nil {
ds.logger.Warn("Failed to connect", "Message", err)
- return fmt.Errorf("Failed to connect to server, please inspect Grafana server log for details")
+
+ return &backend.CheckHealthResult{
+ Status: backend.HealthStatusError,
+ Message: "Failed to connect to server, please inspect Grafana server log for details",
+ }, nil
}
- return nil
+ return &backend.CheckHealthResult{
+ Status: backend.HealthStatusOk,
+ Message: "Database connected",
+ }, nil
}
func processQueries(req *backend.QueryDataRequest, handler func(*backend.PluginContext, backend.DataQuery) backend.DataResponse) backend.Responses {
@@ -247,7 +254,8 @@ func (ds *CassandraDatasource) metricQuery(query *backend.DataQuery) (data.Frame
err := json.Unmarshal(query.JSON, &cassQuery)
if err != nil {
ds.logger.Error("Failed to parse queries", "Message", err)
- return nil, fmt.Errorf("Failed to parse queries, please inspect Grafana server log for details")
+
+ return nil, errors.New("Failed to parse queries, please inspect Grafana server log for details")
}
if cassQuery.RawQuery {
@@ -267,35 +275,44 @@ func (ds *CassandraDatasource) getRequestOptions(jsonData []byte) (DataSourceOpt
err := json.Unmarshal(jsonData, &options)
if err != nil {
ds.logger.Error("Failed to parse request", "Message", err)
- return options, fmt.Errorf("Failed to parse request, please inspect Grafana server log for details")
+
+ return options, errors.New("Failed to parse request, please inspect Grafana server log for details")
}
return options, nil
}
-func (ds *CassandraDatasource) connect(context *backend.PluginContext) (bool, error) {
- options, err := ds.getRequestOptions(context.DataSourceInstanceSettings.JSONData)
- if err != nil {
- ds.logger.Error("Failed to parse connection parameters", "Message", err)
- return false, fmt.Errorf("Failed to parse connection parameters, please inspect Grafana server log for details")
+func (ds *CassandraDatasource) connectIfNeeded(context *backend.PluginContext) error {
+ if ds.session != nil {
+ return nil
}
- datasourceID := int(context.DataSourceInstanceSettings.ID)
+ return ds.connect(context)
+}
- if ds.sessions == nil {
- ds.sessions = make(map[int]*gocql.Session)
- }
+func (ds *CassandraDatasource) connect(context *backend.PluginContext) error {
+ hosts := strings.Split(context.DataSourceInstanceSettings.URL, ";")
- if ds.sessions[datasourceID] != nil {
- ds.session = ds.sessions[datasourceID]
+ err := ds.tryToConnect(hosts, context)
+ if err != nil {
+ ds.logger.Error("Failed to connect", "Message", err)
- return true, nil
+ return errors.New("Failed to connect, please inspect Grafana server log for details")
}
- host := context.DataSourceInstanceSettings.URL
+ return nil
+}
+
+func (ds *CassandraDatasource) tryToConnect(hosts []string, context *backend.PluginContext) error {
+ options, err := ds.getRequestOptions(context.DataSourceInstanceSettings.JSONData)
+ if err != nil {
+ ds.logger.Error("Failed to parse connection parameters", "Message", err)
- ds.logger.Debug(fmt.Sprintf("Connecting to %s...\n", host))
+ return errors.New("Failed to parse connection parameters, please inspect Grafana server log for details")
+ }
- cluster := gocql.NewCluster(host)
+ ds.logger.Debug("Connecting", "Hosts", hosts)
+
+ cluster := gocql.NewCluster(hosts...)
if options.Timeout != nil {
cluster.Timeout = time.Duration(*options.Timeout) * time.Second
@@ -304,7 +321,8 @@ func (ds *CassandraDatasource) connect(context *backend.PluginContext) (bool, er
consistency, err := parseConsistency(options.Consistency)
if err != nil {
ds.logger.Error("Failed to parse consistency", "Message", err, "Consistency", options.Consistency)
- return false, fmt.Errorf("Failed to parse consistency, please inspect Grafana server log for details")
+
+ return errors.New("Failed to parse consistency, please inspect Grafana server log for details")
}
cluster.Consistency = consistency
@@ -321,7 +339,8 @@ func (ds *CassandraDatasource) connect(context *backend.PluginContext) (bool, er
tlsConfig, err := PrepareTLSCfg(options.CertPath, options.RootPath, options.CaPath, options.AllowInsecureTLS)
if err != nil {
ds.logger.Error("Failed to create TLS config", "Message", err)
- return false, fmt.Errorf("Failed to create TLS config, please inspect Grafana server log for details")
+
+ return errors.New("Failed to create TLS config, please inspect Grafana server log for details")
}
cluster.SslOpts = &gocql.SslOptions{Config: tlsConfig}
@@ -330,14 +349,13 @@ func (ds *CassandraDatasource) connect(context *backend.PluginContext) (bool, er
session, err := cluster.CreateSession()
if err != nil {
ds.logger.Warn("Failed to create session", "Message", err)
- return false, fmt.Errorf("Failed to create Cassandra session, please inspect Grafana server log for details")
+
+ return errors.New("Failed to create Cassandra session, please inspect Grafana server log for details")
}
- ds.sessions[datasourceID] = session
ds.session = session
- ds.logger.Debug("Connection successful")
- return true, nil
+ return nil
}
func parseConsistency(consistencyStr string) (consistency gocql.Consistency, err error) {
diff --git a/backend/plugin.go b/backend/plugin.go
index 3f3dece..7249ddd 100644
--- a/backend/plugin.go
+++ b/backend/plugin.go
@@ -59,18 +59,7 @@ func (handler *Handler) CheckHealth(ctx context.Context, req *backend.CheckHealt
}, nil
}
- err = datasource.CheckHealth(ctx, req)
- if err != nil {
- return &backend.CheckHealthResult{
- Status: backend.HealthStatusError,
- Message: fmt.Sprintf("Connection test failed, error = %v", err),
- }, nil
- }
-
- return &backend.CheckHealthResult{
- Status: backend.HealthStatusOk,
- Message: "Database connected",
- }, nil
+ return datasource.CheckHealth(ctx, req)
}
func NewHandler() *Handler {