Java 使用 dropwizard 使用环境变量覆盖服务器连接器配置
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Overriding server connector config with env variables with dropwizard
提问by StephenNYC
I have posted this question on dw mailing list but didnt get an answer.
我已经在 dw 邮件列表上发布了这个问题，但没有得到答案。
Can I assume the YML format below doesnt work for DW 0.7.0 anymore? (The use of @ char to insert env var)
我可以假设下面的 YML 格式不再适用于 DW 0.7.0 吗？（使用@char 插入env var）
server:
applicationConnectors:
- type: http
bindHost: @OPENSHIFT_DIY_IP@
port: @OPENSHIFT_DIY_PORT@
Error:
错误：
Malformed YAML at line: 28, column: 17; while scanning for the next token; found character @ '@' that cannot start any token. (Do not use @ for indentation); in 'reader', line 28, column 17: bindHost: @OPENSHIFT_DIY_IP@
格式错误的 YAML 第 28 行，第 17 列；在扫描下一个令牌时；发现无法开始任何标记的字符@'@'。（不要使用@ 缩进）；在“读者”中，第 28 行，第 17 列：bindHost：@OPENSHIFT_DIY_IP@
So I decided to use this format:
所以我决定使用这种格式：
server:
type: simple
applicationContextPath: /
adminContextPath: /admin
connector:
type: http
bindHost: localhost
port: 8080
And tried to override it via jvm options:
并尝试通过 jvm 选项覆盖它：
java -Ddw.server.connector.bindHost=$OPENSHIFT_DIY_IP -Ddw.server.connector.port=$OPENSHIFT_DIY_PORT -jar target/myapp.jar server myapp.yml
My local env variables:
我的本地环境变量：
OPENSHIFT_DIY_IP=localhost
OPENSHIFT_DIY_PORT=8080
The error I got from this setup:
我从这个设置中得到的错误：
Exception in thread "main" java.lang.RuntimeException: java.net.SocketException: Unresolved address at org.eclipse.jetty.setuid.SetUIDListener.lifeCycleStarting(SetUIDListener.java:213) ... Caused by: java.net.SocketException: Unresolved address at sun.nio.ch.Net.translateToSocketException(Net.java:157) ... WARN [2014-05-03 20:11:19,412] org.eclipse.jetty.util.component.AbstractLifeCycle: FAILED org.eclipse.jetty.server.Server@91b85: java.lang.RuntimeException: java.net.SocketException: Unresolved address
线程“main”中的异常 java.lang.RuntimeException: java.net.SocketException: Unresolved address at org.eclipse.jetty.setuid.SetUIDListener.lifeCycleStarting(SetUIDListener.java:213) ... 引起：java.net.SocketException ：sun.nio.ch.Net.translateToSocketException(Net.java:157) 处的未解析地址...警告 [2014-05-03 20:11:19,412] org.eclipse.jetty.util.component.AbstractLifeCycle: FAILED org .eclipse.jetty.server.Server@91b85: java.lang.RuntimeException: java.net.SocketException: 未解析地址
What am I doing wrong?
我究竟做错了什么？
采纳答案by StephenNYC
回答by WarFox
Starting from Dropwizard version 0.8.0, you can access environment variables from the configuration yml file. It also supports setting a default value in case the environment variable is not available. See the docs here.
从 Dropwizard 版本0.8.0 开始，您可以从配置 yml 文件访问环境变量。它还支持在环境变量不可用的情况下设置默认值。 请参阅此处的文档。
Example
例子
// put environment variable inside ${}
// use :- operator to provide default value
dbHost: ${DB_HOST}
dbPort: ${DB_PORT:-1234}
// dbPort = 1234, if DB_PORT environment variable has no value
Important Note: For this to work you need to set up a SubstitutingSourceProviderwith an EnvironmentVariableSubstitutor.
重要说明：要使其正常工作，您需要设置一个SubstitutingSourceProvider带有EnvironmentVariableSubstitutor.
// Enable variable substitution with environment variables
bootstrap.setConfigurationSourceProvider(
new SubstitutingSourceProvider(
bootstrap.getConfigurationSourceProvider(),
new EnvironmentVariableSubstitutor())
);
Update: 15/Nov/2017
As mentioned by @EFreak in the comments section, new EnvironmentVariableSubstitutor()will throw UndefinedEnvironmentVariableExceptionif the environment variable is not defined, unless you set strictmode to falseby using new EnvironmentVariableSubstitutor(false)https://github.com/dropwizard/dropwizard/blob/master/dropwizard-configuration/src/main/java/io/dropwizard/configuration/EnvironmentVariableSubstitutor.java
更新：15/Nov/2017 正如@EFreak 在评论部分所提到的，如果未定义环境变量，new EnvironmentVariableSubstitutor()则会抛出异常UndefinedEnvironmentVariableException，除非您使用https://github.com/dropwizard/dropwizard/blob/master/将strict模式设置为dropwizard-configuration/src/main/java/io/dropwizard/configuration/EnvironmentVariableSubstitutor.javafalsenew EnvironmentVariableSubstitutor(false)
