From ee2cc49ba1d7ce640992250413acda372fefee96 Mon Sep 17 00:00:00 2001
From: Alexander Zobnin <alexanderzobnin@gmail.com>
Date: Mon, 1 Jun 2020 12:50:22 +0300
Subject: [PATCH] do not cache history requests

---
 pkg/datasource.go       |  2 +-
 pkg/resource_handler.go |  1 -
 pkg/zabbix_api.go       | 14 ++++++++++++--
 pkg/zabbix_api_core.go  |  1 +
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/pkg/datasource.go b/pkg/datasource.go
index 8ee827e..82b1e5f 100644
--- a/pkg/datasource.go
+++ b/pkg/datasource.go
@@ -131,7 +131,7 @@ func newZabbixDatasource(dsInfo *backend.DataSourceInstanceSettings) (*ZabbixDat
 		url:        zabbixURL,
 		dsInfo:     dsInfo,
 		Settings:   zabbixSettings,
-		queryCache: NewCache(10*time.Minute, 10*time.Minute),
+		queryCache: NewCache(zabbixSettings.CacheTTL, 10*time.Minute),
 		httpClient: &http.Client{
 			Transport: &http.Transport{
 				TLSClientConfig: &tls.Config{
diff --git a/pkg/resource_handler.go b/pkg/resource_handler.go
index bc7e290..b90790c 100644
--- a/pkg/resource_handler.go
+++ b/pkg/resource_handler.go
@@ -38,7 +38,6 @@ func (ds *ZabbixDatasource) zabbixAPIHandler(rw http.ResponseWriter, req *http.R
 	pluginCxt := httpadapter.PluginConfigFromContext(req.Context())
 	dsInstance, err := ds.GetDatasource(pluginCxt)
 
-	ds.logger.Debug("Invoke Zabbix API call", "ds", pluginCxt.DataSourceInstanceSettings.Name, "method", reqData.Method)
 	apiReq := &ZabbixAPIRequest{Method: reqData.Method, Params: reqData.Params}
 
 	result, err := dsInstance.ZabbixAPIQuery(req.Context(), apiReq)
diff --git a/pkg/zabbix_api.go b/pkg/zabbix_api.go
index aac286f..d048490 100644
--- a/pkg/zabbix_api.go
+++ b/pkg/zabbix_api.go
@@ -13,16 +13,26 @@ import (
 	"golang.org/x/net/context"
 )
 
+var NotCachedMethods = map[string]bool{
+	"history.get": true,
+	"trend.get":   true,
+}
+
 // ZabbixAPIQuery handles query requests to Zabbix
 func (ds *ZabbixDatasourceInstance) ZabbixAPIQuery(ctx context.Context, apiReq *ZabbixAPIRequest) (*ZabbixAPIResourceResponse, error) {
 	var result interface{}
 	var err error
 	var queryExistInCache bool
-	result, queryExistInCache = ds.queryCache.Get(HashString(apiReq.String()))
+	requestHash := HashString(apiReq.String())
+	result, queryExistInCache = ds.queryCache.Get(requestHash)
 
 	if !queryExistInCache {
 		result, err = ds.ZabbixRequest(ctx, apiReq.Method, apiReq.Params)
-		ds.queryCache.Set(HashString(apiReq.String()), result)
+
+		if _, ok := NotCachedMethods[apiReq.Method]; !ok {
+			ds.logger.Debug("Write result to cache", "method", apiReq.Method)
+			ds.queryCache.Set(HashString(apiReq.String()), result)
+		}
 		if err != nil {
 			return nil, err
 		}
diff --git a/pkg/zabbix_api_core.go b/pkg/zabbix_api_core.go
index eb145ed..848e27f 100644
--- a/pkg/zabbix_api_core.go
+++ b/pkg/zabbix_api_core.go
@@ -16,6 +16,7 @@ import (
 
 // ZabbixRequest checks authentication and makes a request to the Zabbix API
 func (ds *ZabbixDatasourceInstance) ZabbixRequest(ctx context.Context, method string, params ZabbixAPIParams) (*simplejson.Json, error) {
+	ds.logger.Debug("Invoke Zabbix API request", "ds", ds.dsInfo.Name, "method", method)
 	var result *simplejson.Json
 	var err error