hana.go

/*
http://www.apache.org/licenses/LICENSE-2.0.txt


Copyright 2015 Intel Corporation

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package hana

import (
	"bytes"
	"database/sql"
	"encoding/gob"
	"errors"
	"fmt"
	"reflect"
	"strconv"
	"strings"

	log "github.com/sirupsen/logrus"

	"github.com/SAP/go-hdb/driver"
	"github.com/intelsdi-x/snap/control/plugin"
	"github.com/intelsdi-x/snap/control/plugin/cpolicy"
	"github.com/intelsdi-x/snap/core"
	"github.com/intelsdi-x/snap/core/ctypes"
)

const (
	name       = "hana"
	version    = 6
	pluginType = plugin.PublisherPluginType
)

type HANAPublisher struct {
}

func NewHANAPublisher() *HANAPublisher {
	return &HANAPublisher{}
}

// Publish sends data to a HANA server
func (s *HANAPublisher) Publish(contentType string, content []byte, config map[string]ctypes.ConfigValue) error {
	logger := log.New()
	logger.Println("Publishing started")
	var metrics []plugin.MetricType

	switch contentType {
	case plugin.SnapGOBContentType:
		dec := gob.NewDecoder(bytes.NewBuffer(content))
		if err := dec.Decode(&metrics); err != nil {
			logger.Printf("Error decoding: error=%v content=%v", err, content)
			return err
		}
	default:
		logger.Printf("Error unknown content type '%v'", contentType)
		return errors.New(fmt.Sprintf("Unknown content type '%s'", contentType))
	}

	logger.Printf("publishing %v to %v", metrics, config)

	// Open connection and ping to make sure it works
	username := config["username"].(ctypes.ConfigValueStr).Value
	password := config["password"].(ctypes.ConfigValueStr).Value
	host := config["host"].(ctypes.ConfigValueStr).Value
	database := config["database"].(ctypes.ConfigValueStr).Value
	port := config["port"].(ctypes.ConfigValueStr).Value
	tableName := config["tablename"].(ctypes.ConfigValueStr).Value
	tableColumns := "(timestamp VARCHAR(200), source VARCHAR(200), key VARCHAR(200), value VARCHAR(200))"
	db, err := sql.Open(driver.DriverName, "hdb://"+username+":"+password+"@"+host+":"+port+"/"+database)
	defer db.Close()
	if err != nil {
		logger.Printf("Error: %v", err)
		return err
	}
	err = db.Ping()
	if err != nil {
		logger.Printf("Error: %v", err)
		return err
	}

	// Create the table if it's not already there
	_, err = db.Exec("DROP PROCEDURE ifexists")

	if err != nil {
		logger.Printf("Error while dropping procedure: %v", err)
	}

	createTableStr :=
		"CREATE PROCEDURE ifexists( ) LANGUAGE SQLSCRIPT AS myrowid integer;\n" +
			"BEGIN\n" +
			" myrowid := 0;\n" +
			" SELECT COUNT(*) INTO myrowid FROM \"PUBLIC\".\"M_TABLES\" " +
			" WHERE schema_name = '" + database + "' AND table_name = '" + tableName + "';\n" +
			" IF :myrowid = 0 THEN\n" +
			"  exec 'CREATE COLUMN TABLE \"" + database + "\".\"" + tableName + "\" " + tableColumns + "';\n " +
			" END IF;\n" +
			"END;"

	_, err = db.Exec(createTableStr)

	if err != nil {
		logger.Printf("Error while creating procedure: %v", err)
		logger.Printf("Query: %v", createTableStr)
	}

	_, err = db.Exec("CALL ifexists")

	if err != nil {
		logger.Printf("Error while invoking procedure: %v", err)

		return err
	}

	// Put the values into the database with the current time
	tableValues := "VALUES( ?, ?, ?, ? )"
	insert, err := db.Prepare("INSERT INTO " + database + "." + tableName + " " + tableValues)
	if err != nil {
		logger.Printf("Error: %v", err)
		logger.Printf("tablename: " + database + "." + tableName + ", tableValues: " + tableValues)
		return err
	}

	var key, value string
	for _, m := range metrics {
		key = sliceToString(m.Namespace().Strings())
		value, err = interfaceToString(m.Data())
		if err != nil {
			logger.Printf("Error: %v", err)
			return err
		}
		_, err = insert.Exec(m.Timestamp(), m.Tags()[core.STD_TAG_PLUGIN_RUNNING_ON], key, value)
		if err != nil {
			logger.Printf("Error: %v", err)
			return err
		}
	}

	return nil
}

func Meta() *plugin.PluginMeta {
	return plugin.NewPluginMeta(name, version, pluginType, []string{plugin.SnapGOBContentType}, []string{plugin.SnapGOBContentType})
}

func (f *HANAPublisher) GetConfigPolicy() (*cpolicy.ConfigPolicy, error) {
	cp := cpolicy.New()
	config := cpolicy.NewPolicyNode()

	host, err := cpolicy.NewStringRule("host", true, "root")
	handleErr(err)
	host.Description = "HANA host to which we will connect"

	port, err := cpolicy.NewStringRule("port", true, "30017")
	handleErr(err)
	port.Description = "HANA port to which we will connect"

	username, err := cpolicy.NewStringRule("username", true, "root")
	handleErr(err)
	username.Description = "Username to login to the HANA server"

	password, err := cpolicy.NewStringRule("password", true, "root")
	handleErr(err)
	password.Description = "Password to login to the HANA server"

	database, err := cpolicy.NewStringRule("database", true, "SNAP_TEST")
	handleErr(err)
	database.Description = "The HANA database that data will be pushed to"

	tableName, err := cpolicy.NewStringRule("tablename", true, "info")
	handleErr(err)
	tableName.Description = "The HANA table within the database where information will be stored"

	config.Add(
		host,
		username,
		password,
		database,
		port,
		tableName,
	)

	cp.Add([]string{""}, config)
	return cp, nil
}

func handleErr(e error) {
	if e != nil {
		panic(e)
	}
}

func sliceToString(slice []string) string {
	return strings.Join(slice, ", ")
}

// Supported types: []string, []int, int, uint64, float32, float64, string
func interfaceToString(face interface{}) (string, error) {
	var (
		ret string
		err error
	)
	switch val := face.(type) {
	case []string:
		ret = sliceToString(val)
	case []int:
		length := len(val)
		if length == 0 {
			return ret, err
		}
		ret = strconv.Itoa(val[0])
		if length == 1 {
			return ret, err
		}
		for i := 1; i < length; i++ {
			ret += ", "
			ret += strconv.Itoa(val[i])
		}
	case int:
		ret = strconv.Itoa(val)
	case uint64:
		ret = strconv.FormatUint(val, 10)
	case float32:
		ret = strconv.FormatFloat(float64(val), 'E', -1, 32)
	case float64:
		ret = strconv.FormatFloat(val, 'E', -1, 64)
	case string:
		ret = val
	default:
		err = errors.New("Unsupported type: " + reflect.TypeOf(face).String())
	}
	return ret, err
}