aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/OpenSim/Data/Migration.cs
blob: 75d5307e8e2c4c518c7c12771e26e2afab5b7882 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.IO;
using System.Reflection;
using System.Text.RegularExpressions;
using log4net;

namespace OpenSim.Data
{
    /// <summary> 
    ///
    /// The Migration theory is based on the ruby on rails concept.
    /// Each database driver is going to be allowed to have files in
    /// Resources that specify the database migrations.  They will be
    /// of the form:
    ///
    ///    001_Users.sql
    ///    002_Users.sql
    ///    003_Users.sql
    ///    001_Prims.sql
    ///    002_Prims.sql
    ///    ...etc...
    ///
    /// When a database driver starts up, it specifies a resource that
    /// needs to be brought up to the current revision.  For instance:
    ///
    ///    Migration um = new Migration(Assembly, DbConnection, "Users");
    ///    um.Upgrade();
    ///
    /// This works out which version Users is at, and applies all the
    /// revisions past it to it.  If there is no users table, all
    /// revisions are applied in order.  Consider each future
    /// migration to be an incremental roll forward of the tables in
    /// question.
    ///
    /// Assembly must be specifically passed in because otherwise you
    /// get the assembly that Migration.cs is part of, and what you
    /// really want is the assembly of your database class.
    ///
    /// </summary>

    public class Migration
    {
        private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private string _type;
        private DbConnection _conn;
        private string _subtype;
        private Assembly _assem;
        
        private static readonly string _migrations_create = "create table migrations(name varchar(100), version int)";
        private static readonly string _migrations_init = "insert into migrations values('migrations', 1)";
        private static readonly string _migrations_find = "select version from migrations where name='migrations'";
        
        public Migration(DbConnection conn, Assembly assem, string type)
        {
            _type = type;
            _conn = conn;
            _assem = assem;
            
            Initialize();
        }

        private void Initialize()
        {
            // clever, eh, we figure out which migrations version we are
            int migration_version = FindVersion("migrations");

            if (migration_version > 0) 
                return;

            // If not, create the migration tables
            DbCommand cmd = _conn.CreateCommand();
            cmd.CommandText = _migrations_create;
            cmd.ExecuteNonQuery();

            InsertVersion("migrations", 1);
        }

        public void Update()
        {
            int version = 0;
            int newversion = 0;
            version = FindVersion(_type);

            List<string> migrations = GetMigrationsAfter(version);
            DbCommand cmd = _conn.CreateCommand();
            foreach (string m in migrations) 
            {
                cmd.CommandText = m;
                cmd.ExecuteNonQuery();
            }

            newversion = MaxVersion();
            if (newversion > version)
            {
                if (version == 0)
                {
                    InsertVersion(_type, newversion);
                }
                else
                {
                    UpdateVersion(_type, newversion);
                }
            }
        }

        private int MaxVersion()
        {
            int max = 0;
            
            string[] names = _assem.GetManifestResourceNames();
            List<string> migrations = new List<string>();
            Regex r = new Regex(@"\.(\d\d\d)_" + _type + @"\.sql");

            foreach (string s in names)
            {
                Match m = r.Match(s);
                if (m.Success) 
                {
                    int MigrationVersion = int.Parse(m.Groups[1].ToString());
                    if (MigrationVersion > max)
                        max = MigrationVersion;
                }
            }
            return max;
        }

        private int FindVersion(string type) 
        {
            int version = 0;
            DbCommand cmd = _conn.CreateCommand();
            try
            {
                cmd.CommandText = "select version from migrations where name='" + type + "' limit 1";
                using (IDataReader reader = cmd.ExecuteReader())
                {
                    if (reader.Read())
                    {
                        version = Convert.ToInt32(reader["version"]);
                    }
                    reader.Close();
                }
            }
            catch
            {
                // Something went wrong, so we're version 0
            }
            return version;
        }

        private void InsertVersion(string type, int version) 
        {
            DbCommand cmd = _conn.CreateCommand();
            cmd.CommandText = "insert into migrations(name, version) values('" + type + "', " + version + ")";
            m_log.InfoFormat("Creating {0} at version {1}", type, version);
            cmd.ExecuteNonQuery();
        }
        
        private void UpdateVersion(string type, int version) 
        {
            DbCommand cmd = _conn.CreateCommand();
            cmd.CommandText = "update migrations set version=" + version + " where name='" + type + "'";
            m_log.InfoFormat("Updating {0} to version {1}", type, version);
            cmd.ExecuteNonQuery();
        }
        
        private List<string> GetAllMigrations()
        {
            return GetMigrationsAfter(0);
        }

        private List<string> GetMigrationsAfter(int version)
        {
            string[] names = _assem.GetManifestResourceNames();
            List<string> migrations = new List<string>();

            Regex r = new Regex(@"^(\d\d\d)_" + _type + @"\.sql");

            foreach (string s in names)
            {
                Match m = r.Match(s);
                if (m.Success)
                {
                    m_log.Info("MIGRATION: Match: " + m.Groups[1].ToString());
                    int MigrationVersion = int.Parse(m.Groups[1].ToString());
                    using (Stream resource = _assem.GetManifestResourceStream(s))
                    {
                        using (StreamReader resourceReader = new StreamReader(resource))
                        {
                            string resourceString = resourceReader.ReadToEnd();
                            migrations.Add(resourceString);
                        }
                    }
                }
            }

            // TODO: once this is working, get rid of this
            if (migrations.Count < 1)
            {
                m_log.InfoFormat("Resource '{0}' was not found", _type);
            }
            return migrations;
        }
    }
}