Mon, 04 Jan 2021 15:34:41 +0100
ordinals may be signed
151 | 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 | /** | |
38 | * Provides access to the database. | |
39 | */ | |
40 | @WebListener | |
41 | class DataSourceProvider : ServletContextListener, LoggingTrait { | |
42 | ||
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43 | enum class Dialect { |
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44 | Postgres |
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parents:
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45 | } |
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parents:
151
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changeset
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46 | |
151 | 47 | /** |
48 | * The database dialect to use. | |
49 | * May be overridden by context parameter. | |
50 | * | |
51 | * @see Constants.CTX_ATTR_DB_DIALECT | |
52 | */ | |
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53 | var dialect = Dialect.Postgres; private set |
151 | 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 | |
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131 | sc.getInitParameter(Constants.CTX_ATTR_DB_DIALECT)?.let { dbDialect -> |
151 | 132 | try { |
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parents:
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133 | dialect = Dialect.valueOf(dbDialect) |
151 | 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 | } |