1// Copyright 2011 The Kyua Authors.
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27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29#include "store/migrate.hpp"
30
31#include <stdexcept>
32
33#include "store/dbtypes.hpp"
34#include "store/exceptions.hpp"
35#include "store/layout.hpp"
36#include "store/metadata.hpp"
37#include "store/read_backend.hpp"
38#include "store/write_backend.hpp"
39#include "utils/datetime.hpp"
40#include "utils/env.hpp"
41#include "utils/format/macros.hpp"
42#include "utils/fs/exceptions.hpp"
43#include "utils/fs/operations.hpp"
44#include "utils/fs/path.hpp"
45#include "utils/logging/macros.hpp"
46#include "utils/optional.ipp"
47#include "utils/sanity.hpp"
48#include "utils/stream.hpp"
49#include "utils/sqlite/database.hpp"
50#include "utils/sqlite/exceptions.hpp"
51#include "utils/sqlite/statement.ipp"
52#include "utils/text/operations.hpp"
53
54namespace datetime = utils::datetime;
55namespace fs = utils::fs;
56namespace sqlite = utils::sqlite;
57namespace text = utils::text;
58
59using utils::none;
60using utils::optional;
61
62
63namespace {
64
65
66/// Schema version at which we switched to results files.
67const int first_chunked_schema_version = 3;
68
69
70/// Queries the schema version of the given database.
71///
72/// \param file The database from which to query the schema version.
73///
74/// \return The schema version number.
75static int
76get_schema_version(const fs::path& file)
77{
78    sqlite::database db = store::detail::open_and_setup(
79        file, sqlite::open_readonly);
80    return store::metadata::fetch_latest(db).schema_version();
81}
82
83
84/// Performs a single migration step.
85///
86/// Both action_id and old_database are little hacks to support the migration
87/// from the historical database to chunked files.  We'd use a more generic
88/// "replacements" map, but it's not worth it.
89///
90/// \param file Database on which to apply the migration step.
91/// \param version_from Current schema version in the database.
92/// \param version_to Schema version to migrate to.
93/// \param action_id If not none, replace ACTION_ID in the migration file with
94///     this value.
95/// \param old_database If not none, replace OLD_DATABASE in the migration
96///     file with this value.
97///
98/// \throw error If there is a problem applying the migration.
99static void
100migrate_schema_step(const fs::path& file,
101                    const int version_from,
102                    const int version_to,
103                    const optional< int64_t > action_id = none,
104                    const optional< fs::path > old_database = none)
105{
106    LI(F("Migrating schema of %s from version %s to %s") % file % version_from
107       % version_to);
108
109    PRE(version_to == version_from + 1);
110
111    sqlite::database db = store::detail::open_and_setup(
112        file, sqlite::open_readwrite);
113
114    const fs::path migration = store::detail::migration_file(version_from,
115                                                             version_to);
116
117    std::string migration_string;
118    try {
119        migration_string = utils::read_file(migration);
120    } catch (const std::runtime_error& unused_e) {
121        throw store::error(F("Cannot read migration file '%s'") % migration);
122    }
123    if (action_id) {
124        migration_string = text::replace_all(migration_string, "@ACTION_ID@",
125                                             F("%s") % action_id.get());
126    }
127    if (old_database) {
128        migration_string = text::replace_all(migration_string, "@OLD_DATABASE@",
129                                             old_database.get().str());
130    }
131    try {
132        db.exec(migration_string);
133    } catch (const sqlite::error& e) {
134        throw store::error(F("Schema migration failed: %s") % e.what());
135    }
136}
137
138
139/// Given a historical database, chunks it up into results files.
140///
141/// The given database is DELETED on success given that it will have been
142/// split up into various different files.
143///
144/// \param old_file Path to the old database.
145static void
146chunk_database(const fs::path& old_file)
147{
148    PRE(get_schema_version(old_file) == first_chunked_schema_version - 1);
149
150    LI(F("Need to split %s into per-action files") % old_file);
151
152    sqlite::database old_db = store::detail::open_and_setup(
153        old_file, sqlite::open_readonly);
154
155    sqlite::statement actions_stmt = old_db.create_statement(
156        "SELECT action_id, cwd FROM actions NATURAL JOIN contexts");
157
158    sqlite::statement start_time_stmt = old_db.create_statement(
159        "SELECT test_results.start_time AS start_time "
160        "FROM test_programs "
161        "    JOIN test_cases "
162        "        ON test_programs.test_program_id == test_cases.test_program_id"
163        "    JOIN test_results "
164        "        ON test_cases.test_case_id == test_results.test_case_id "
165        "WHERE test_programs.action_id == :action_id "
166        "ORDER BY start_time LIMIT 1");
167
168    while (actions_stmt.step()) {
169        const int64_t action_id = actions_stmt.safe_column_int64("action_id");
170        const fs::path cwd(actions_stmt.safe_column_text("cwd"));
171
172        LI(F("Extracting action %s") % action_id);
173
174        start_time_stmt.reset();
175        start_time_stmt.bind(":action_id", action_id);
176        if (!start_time_stmt.step()) {
177            LI(F("Skipping empty action %s") % action_id);
178            continue;
179        }
180        const datetime::timestamp start_time = store::column_timestamp(
181            start_time_stmt, "start_time");
182        start_time_stmt.step_without_results();
183
184        const fs::path new_file = store::layout::new_db_for_migration(
185            cwd, start_time);
186        if (fs::exists(new_file)) {
187            LI(F("Skipping action because %s already exists") % new_file);
188            continue;
189        }
190
191        LI(F("Creating %s for previous action %s") % new_file % action_id);
192
193        try {
194            fs::mkdir_p(new_file.branch_path(), 0755);
195            sqlite::database db = store::detail::open_and_setup(
196                new_file, sqlite::open_readwrite | sqlite::open_create);
197            store::detail::initialize(db);
198            db.close();
199            migrate_schema_step(new_file,
200                                first_chunked_schema_version - 1,
201                                first_chunked_schema_version,
202                                utils::make_optional(action_id),
203                                utils::make_optional(old_file));
204        } catch (...) {
205            // TODO(jmmv): Handle this better.
206            fs::unlink(new_file);
207        }
208    }
209
210    fs::unlink(old_file);
211}
212
213
214}  // anonymous namespace
215
216
217/// Calculates the path to a schema migration file.
218///
219/// \param version_from The version from which the database is being upgraded.
220/// \param version_to The version to which the database is being upgraded.
221///
222/// \return The path to the installed migrate_vX_vY.sql file.
223fs::path
224store::detail::migration_file(const int version_from, const int version_to)
225{
226    return fs::path(utils::getenv_with_default("KYUA_STOREDIR", KYUA_STOREDIR))
227        / (F("migrate_v%s_v%s.sql") % version_from % version_to);
228}
229
230
231/// Backs up a database for schema migration purposes.
232///
233/// \todo We should probably use the SQLite backup API instead of doing a raw
234/// file copy.  We issue our backup call with the database already open, but
235/// because it is quiescent, it's OK to do so.
236///
237/// \param source Location of the database to be backed up.
238/// \param old_version Version of the database's CURRENT schema, used to
239///     determine the name of the backup file.
240///
241/// \throw error If there is a problem during the backup.
242void
243store::detail::backup_database(const fs::path& source, const int old_version)
244{
245    const fs::path target(F("%s.v%s.backup") % source.str() % old_version);
246
247    LI(F("Backing up database %s to %s") % source % target);
248    try {
249        fs::copy(source, target);
250    } catch (const fs::error& e) {
251        throw store::error(e.what());
252    }
253}
254
255
256/// Migrates the schema of a database to the current version.
257///
258/// The algorithm implemented here performs a migration step for every
259/// intermediate version between the schema version in the database to the
260/// version implemented in this file.  This should permit upgrades from
261/// arbitrary old databases.
262///
263/// \param file The database whose schema to upgrade.
264///
265/// \throw error If there is a problem with the migration.
266void
267store::migrate_schema(const utils::fs::path& file)
268{
269    const int version_from = get_schema_version(file);
270    const int version_to = detail::current_schema_version;
271    if (version_from == version_to) {
272        throw error(F("Database already at schema version %s; migration not "
273                      "needed") % version_from);
274    } else if (version_from > version_to) {
275        throw error(F("Database at schema version %s, which is newer than the "
276                      "supported version %s") % version_from % version_to);
277    }
278
279    detail::backup_database(file, version_from);
280
281    int i;
282    for (i = version_from; i < first_chunked_schema_version - 1; ++i) {
283        migrate_schema_step(file, i, i + 1);
284    }
285    chunk_database(file);
286    INV(version_to == first_chunked_schema_version);
287}
288