X-Git-Url: http://git.iain.cx/?a=blobdiff_plain;f=lib%2Fglobal_variables.go;fp=lib%2Fglobal_variables.go;h=a83ec7edf1f12c5fdb9c1bf8b0f0456bc18106f5;hb=38376bf5db9af25660b8183b2c022d079bb2b5ea;hp=0000000000000000000000000000000000000000;hpb=c24180cda0bbab4ae07c87bf2cdf54e61d358142;p=pstop.git

diff --git a/lib/global_variables.go b/lib/global_variables.go
new file mode 100644
index 0000000..a83ec7e
--- /dev/null
+++ b/lib/global_variables.go
@@ -0,0 +1,94 @@
+package lib
+
+import (
+	"database/sql"
+	"log"
+	"strings"
+)
+
+/*
+** mysql> select VARIABLE_VALUE from information_schema.global_variables where variable_name = 'hostname';
+* +----------------+
+* | VARIABLE_VALUE |
+* +----------------+
+* | myhostname     |
+* +----------------+
+* 1 row in set (0.00 sec)
+**/
+func SelectGlobalVariableByVariableName(dbh *sql.DB, variable_name string) (error, string) {
+	sql_select := "SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME = ?"
+
+	var variable_value string
+	err := dbh.QueryRow(sql_select, variable_name).Scan(&variable_value)
+	switch {
+	case err == sql.ErrNoRows:
+		log.Println("No setting with that variable_name", variable_name)
+	case err != nil:
+		log.Fatal(err)
+	default:
+		// fmt.Println("variable_value for", variable_name, "is", variable_value)
+	}
+
+	return err, variable_value
+}
+
+// Provide a slice of string and get back a hash of variable_name to value.
+// - note the query is case insensitive for variable names.
+// - they key values are lower-cased.
+func SelectGlobalVariablesByVariableName(dbh *sql.DB, wanted []string) (error, map[string]string) {
+	hashref := make(map[string]string)
+
+	// create an IN list to make up the query
+	quoted := make([]string, 0, len(wanted))
+	sql_select := "SELECT VARIABLE_NAME, VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME IN ("
+
+	if len(wanted) == 0 {
+		log.Fatal("SelectGlobalVariablesByVariableName() needs at least one entry")
+	}
+
+	for i := range wanted {
+		quoted = append(quoted, "'"+wanted[i]+"'")
+
+	}
+	sql_select += strings.Join(quoted, ",")
+	sql_select += ")"
+
+	rows, err := dbh.Query(sql_select)
+	defer rows.Close()
+
+	for rows.Next() {
+		var variable, value string
+		if err := rows.Scan(&variable, &value); err != nil {
+			log.Fatal(err)
+		}
+		hashref[strings.ToLower(variable)] = value
+	}
+	if err := rows.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return err, hashref
+}
+
+// Return all global variables as a hashref
+func SelectAllGlobalVariablesByVariableName(dbh *sql.DB) (error, map[string]string) {
+	hashref := make(map[string]string)
+
+	sql_select := "SELECT VARIABLE_NAME, VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES"
+
+	rows, err := dbh.Query(sql_select)
+	defer rows.Close()
+
+	for rows.Next() {
+		var variable, value string
+		if err := rows.Scan(&variable, &value); err != nil {
+			log.Fatal(err)
+		}
+		hashref[strings.ToLower(variable)] = value
+	}
+	if err := rows.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return err, hashref
+}