如何在OpenLiberty的server.xml配置属性文字/变量中使用自定义转换器?

时间:2019-08-08 15:19:47

标签: java ibm-cloud cloudfoundry open-liberty microprofile

我真的很想将容器管理的事务与JPA一起使用,因此可以通过简单的方法在server.xml中创建数据源,然后在我的代码中使用@PersistenceContext。

我当前面临的问题-也许我觉得太复杂-事实是我在运行时在Cloud Foundry环境中以VCAP_SERVICES系统环境变量的身份获取凭据。

此VCAP_SERVICES变量包含带有必需凭据的大JSON。因此,我首先必须在其中提取相应的JSON,然后将其作为属性传递。

我的最初想法是在这种情况下使用转换器从JSON返回值,以便可以使用它们。但是似乎在已定义的配置xml文件中这是不可能的。

我肯定要防止的是“注入”我自己做的事情,例如拥有属性文件并从其中的不同环境DEV,TEST,PROD复制值,因为Cloud Foundry环境已经在做为我工作。

所以问题是: 如何将凭证从VCAP_SERVICES系统环境变量获取到server.xml配置中?记住:我真的必须解析VCAP_SERVICES变量,因为它是JSON并提取值。

<?xml version="1.0" encoding="UTF-8"?>
<server description="Config example">

    <featureManager>
        <feature>javaee-8.0</feature>
        <feature>mpMetrics-1.1</feature>
        <feature>monitor-1.0</feature>
    </featureManager>

    <!-- Postgres config-example-db definition -->
    <dataSource id="DefaultDataSource" jndiName="jdbc/config-example" jdbcDriverRef="postgresql-driver"
                type="javax.sql.ConnectionPoolDataSource" transactional="true">

        <properties serverName="config-example-db" portNumber="5432"
                    databaseName="postgres"
                    user="${config-example.db.username}"
                    password="${config-example.db.password}"/>

    </dataSource>

    <basicRegistry id="basic" realm="MicroProfileMetrics">
        <user name="admin" password="adminadmin"/>
        <user name="nonadmin" password="guest"/>
    </basicRegistry>

    <administrator-role>
        <user>admin</user>
    </administrator-role>

</server>

1 个答案:

答案 0 :(得分:0)

对于许多服务,自由构建包将自动配置server.xml。
PostgreSQL是其中之一。看到: https://github.com/cloudfoundry/ibm-websphere-liberty-buildpack/blob/master/docs/services/postgresql.md

此外,对于许多服务,buildpack将创建环境变量,然后可由应用程序访问。

例如,将cloudantNoSQL服务绑定到应用会在VCAP_SERVICES中产生以下凭证:

{
    "binding_name": null,
    "credentials": {
     "apikey": "<apikey>",
     "host": "<host>-bluemix.cloudantnosqldb.test.appdomain.cloud",
     "iam_apikey_description": "Auto-generated for binding <host>",
     "iam_apikey_name": "Cloudant-sd",
     "iam_role_crn": "crn:v1:bluemix:public:iam::::serviceRole:Writer",
     "iam_serviceid_crn": "crn:v1:staging:public:iam-identity::<id>::serviceid:ServiceId-<serviceid>",
     "url": "https://<host>-bluemix.cloudantnosqldb.test.appdomain.cloud",
     "username": "<username>-bluemix"
    },

然后,buildpack将在runtime-vars.xml中创建变量:

 <variable name='cloud.services.Cloudant-sd.label' value='cloudantNoSQLDB'/>
  <variable name='cloud.services.Cloudant-sd.plan' value='Lite'/>
  <variable name='cloud.services.Cloudant-sd.name' value='Cloudant-sd'/>
  <variable name='cloud.services.Cloudant-sd.instance_name' value='Cloudant-sd'/>
  <variable name='cloud.services.Cloudant-sd.connection.apikey' value='<apikey'/>
  <variable name='cloud.services.Cloudant-sd.connection.host' value='<host>-bluemix.cloudantnosqldb.test.appdomain.cloud'/>
  <variable name='cloud.services.Cloudant-sd.connection.iam_apikey_description' value='Auto-generated for binding <host>'/>
  <variable name='cloud.services.Cloudant-sd.connection.iam_apikey_name' value='Cloudant-sd'/>
  <variable name='cloud.services.Cloudant-sd.connection.iam_role_crn' value='crn:v1:bluemix:public:iam::::serviceRole:Writer'/>
  <variable name='cloud.services.Cloudant-sd.connection.iam_serviceid_crn' value='crn:v1:staging:public:iam-identity::<id>::serviceid:ServiceId-<serviceid'/>
  <variable name='cloud.services.Cloudant-sd.connection.url' value='https://<host>-bluemix.cloudantnosqldb.test.appdomain.cloud'/>
  <variable name='cloud.services.Cloudant-sd.connection.username' value='<username>-bluemix'/>

请参见https://cloud.ibm.com/docs/runtimes/liberty?topic=liberty-options_for_pushing#accessing_info_of_bound_services