comparison: src/main/kotlin/de/uapcore/lightpit/DataSourceProvider.kt
src/main/kotlin/de/uapcore/lightpit/DataSourceProvider.kt
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- b3f14cd4f3ab
- child 158
- 4f912cd42876
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| 150:822b7e3d064d | 151:b3f14cd4f3ab |
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| 1 /* | |
| 2 * Copyright 2020 Mike Becker. All rights reserved. | |
| 3 * | |
| 4 * Redistribution and use in source and binary forms, with or without | |
| 5 * modification, are permitted provided that the following conditions are met: | |
| 6 * | |
| 7 * 1. Redistributions of source code must retain the above copyright | |
| 8 * notice, this list of conditions and the following disclaimer. | |
| 9 * | |
| 10 * 2. Redistributions in binary form must reproduce the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer in the | |
| 12 * documentation and/or other materials provided with the distribution. | |
| 13 * | |
| 14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 15 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
| 17 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE | |
| 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
| 20 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| 21 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, | |
| 22 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 24 */ | |
| 25 | |
| 26 package de.uapcore.lightpit | |
| 27 | |
| 28 import java.sql.SQLException | |
| 29 import javax.naming.Context | |
| 30 import javax.naming.InitialContext | |
| 31 import javax.naming.NamingException | |
| 32 import javax.servlet.ServletContextEvent | |
| 33 import javax.servlet.ServletContextListener | |
| 34 import javax.servlet.annotation.WebListener | |
| 35 import javax.sql.DataSource | |
| 36 | |
| 37 enum class DatabaseDialect { | |
| 38 Postgres | |
| 39 } | |
| 40 | |
| 41 /** | |
| 42 * Provides access to the database. | |
| 43 */ | |
| 44 @WebListener | |
| 45 class DataSourceProvider : ServletContextListener, LoggingTrait { | |
| 46 | |
| 47 /** | |
| 48 * The database dialect to use. | |
| 49 * May be overridden by context parameter. | |
| 50 * | |
| 51 * @see Constants.CTX_ATTR_DB_DIALECT | |
| 52 */ | |
| 53 var dialect = DatabaseDialect.Postgres; private set | |
| 54 | |
| 55 /** | |
| 56 * The data source, if available. | |
| 57 */ | |
| 58 var dataSource: DataSource? = null | |
| 59 | |
| 60 companion object { | |
| 61 /** | |
| 62 * The attribute name in the Servlet context under which an instance of this class can be found. | |
| 63 */ | |
| 64 val SC_ATTR_NAME = "lightpit.service.DataSourceProvider" | |
| 65 | |
| 66 /** | |
| 67 * Timeout in seconds for the validation test. | |
| 68 */ | |
| 69 private val DB_TEST_TIMEOUT = 10 | |
| 70 | |
| 71 /** | |
| 72 * The default schema to test against when validating the connection. | |
| 73 * May be overridden by context parameter. | |
| 74 * | |
| 75 * @see Constants.CTX_ATTR_DB_SCHEMA | |
| 76 */ | |
| 77 private val DB_DEFAULT_SCHEMA = "lightpit" | |
| 78 | |
| 79 /** | |
| 80 * The JNDI resource name for the data source. | |
| 81 */ | |
| 82 private val DS_JNDI_NAME = "jdbc/lightpit/app" | |
| 83 } | |
| 84 | |
| 85 private fun checkConnection(ds: DataSource, testSchema: String) { | |
| 86 try { | |
| 87 ds.connection.use { conn -> | |
| 88 if (!conn.isValid(DB_TEST_TIMEOUT)) { | |
| 89 throw SQLException("Validation check failed.") | |
| 90 } | |
| 91 if (conn.isReadOnly) { | |
| 92 throw SQLException("Connection is read-only and thus unusable.") | |
| 93 } | |
| 94 if (conn.schema != testSchema) { | |
| 95 throw SQLException( | |
| 96 String.format( | |
| 97 "Connection is not configured to use the schema %s.", | |
| 98 testSchema | |
| 99 ) | |
| 100 ) | |
| 101 } | |
| 102 val metaData = conn.metaData | |
| 103 logger().info( | |
| 104 "Connections as {} to {}/{} ready to go.", | |
| 105 metaData.userName, | |
| 106 metaData.url, | |
| 107 conn.schema | |
| 108 ) | |
| 109 } | |
| 110 } catch (ex: SQLException) { | |
| 111 logger().error("Checking database connection failed", ex) | |
| 112 } | |
| 113 } | |
| 114 | |
| 115 private fun retrieveDataSource(ctx: Context): DataSource? { | |
| 116 return try { | |
| 117 val ret = ctx.lookup(DS_JNDI_NAME) as DataSource | |
| 118 logger().info("Data source retrieved.") | |
| 119 ret | |
| 120 } catch (ex: NamingException) { | |
| 121 logger().error("Data source {} not available.", DS_JNDI_NAME) | |
| 122 logger().error("Reason for the missing data source: ", ex) | |
| 123 null | |
| 124 } | |
| 125 } | |
| 126 | |
| 127 override fun contextInitialized(sce: ServletContextEvent?) { | |
| 128 val sc = sce!!.servletContext | |
| 129 | |
| 130 val dbSchema = sc.getInitParameter(Constants.CTX_ATTR_DB_SCHEMA) ?: DB_DEFAULT_SCHEMA | |
| 131 sc.getInitParameter(Constants.CTX_ATTR_DB_DIALECT)?.let {dbDialect -> | |
| 132 try { | |
| 133 dialect = DatabaseDialect.valueOf(dbDialect) | |
| 134 } catch (ex: IllegalArgumentException) { | |
| 135 logger().error( | |
| 136 "Unknown or unsupported database dialect {}. Defaulting to {}.", | |
| 137 dbDialect, | |
| 138 dialect | |
| 139 ) | |
| 140 } | |
| 141 } | |
| 142 | |
| 143 dataSource = try { | |
| 144 logger().debug("Trying to access JNDI context ...") | |
| 145 val initialCtx: Context = InitialContext() | |
| 146 val ctx = initialCtx.lookup("java:comp/env") as Context | |
| 147 retrieveDataSource(ctx) | |
| 148 } catch (ex: NamingException) { | |
| 149 logger().error("Cannot access JNDI resources.", ex) | |
| 150 null | |
| 151 } catch (ex: ClassCastException) { | |
| 152 logger().error("Cannot access JNDI resources.", ex) | |
| 153 null | |
| 154 } | |
| 155 | |
| 156 dataSource?.let { checkConnection(it, dbSchema) } | |
| 157 | |
| 158 sc.setAttribute(SC_ATTR_NAME, this) | |
| 159 logger().info("Database facade injected into ServletContext.") | |
| 160 } | |
| 161 | |
| 162 override fun contextDestroyed(sce: ServletContextEvent?) { | |
| 163 dataSource = null | |
| 164 } | |
| 165 } |
