UnknownHostException with spring.config.import https

最小限の reproducer から始め、スタックトレースに示されている ConsulConfigDataLoader と ConsulPropertySources のエントリーポイントを追跡します。consul と configserver のインポートがどのように解析されるかを比較し、そのうえで、報告されている HTTPS インポートを使用して、https をホスト名として解決せずに reproducer が接続できることを確認します。

Spring Boot 2.6.3, Spring Cloud 2021.0.0

Getting an java.net.UnknownHostException: https: nodename nor servname provided, or not known exception when trying to connect to consul with spring.config.import=consul:https://localhost:8500.
P.S. Same config works for configserver: spring.config.import=configserver:https://localhost:8888

Minimal reproducer

Stacktrace:

org.springframework.boot.context.config.ConfigDataResourceNotFoundException: Config data resource '[ConsulConfigDataResource@315f43d5 context = '/localhost:8500/', optional = true, properties = [ConsulConfigProperties@68fa0ba8 enabled = true, prefixes = list['config'], defaultContext = 'application', profileSeparator = ',', format = KEY_VALUE, dataKey = 'data', aclToken = [null], watch = [ConsulConfigProperties.Watch@6c5945a7 waitTime = 55, enabled = true, delay = 1000], failFast = true, name = 'application'], profile = [null]]' via location 'consul:https://localhost:8500' cannot be found
	at org.springframework.boot.context.config.ConfigDataResourceNotFoundException.withLocation(ConfigDataResourceNotFoundException.java:97)
	at org.springframework.boot.context.config.ConfigDataImporter.handle(ConfigDataImporter.java:145)
	at org.springframework.boot.context.config.ConfigDataImporter.load(ConfigDataImporter.java:136)
	at org.springframework.boot.context.config.ConfigDataImporter.resolveAndLoad(ConfigDataImporter.java:86)
	at org.springframework.boot.context.config.ConfigDataEnvironmentContributors.withProcessedImports(ConfigDataEnvironmentContributors.java:116)
	at org.springframework.boot.context.config.ConfigDataEnvironment.processWithProfiles(ConfigDataEnvironment.java:311)
	at org.springframework.boot.context.config.ConfigDataEnvironment.processAndApply(ConfigDataEnvironment.java:232)
	at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:102)
	at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:94)
	at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEnvironmentPreparedEvent(EnvironmentPostProcessorApplicationListener.java:102)
	at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEvent(EnvironmentPostProcessorApplicationListener.java:87)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
	at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:85)
	at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:66)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:120)
	at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:114)
	at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:65)
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:338)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:296)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292)
	at com.example.consulconfigdemo.ConsulConfigDemoApplication.main(ConsulConfigDemoApplication.java:10)
Caused by: org.springframework.cloud.consul.config.ConsulPropertySources$PropertySourceNotFoundException: com.ecwid.consul.transport.TransportException: java.net.UnknownHostException: https: nodename nor servname provided, or not known
	at org.springframework.cloud.consul.config.ConsulPropertySources.createPropertySource(ConsulPropertySources.java:143)
	at org.springframework.cloud.consul.config.ConsulConfigDataLoader.doLoad(ConsulConfigDataLoader.java:66)
	at org.springframework.cloud.consul.config.ConsulConfigDataLoader.load(ConsulConfigDataLoader.java:57)
	at org.springframework.cloud.consul.config.ConsulConfigDataLoader.load(ConsulConfigDataLoader.java:38)
	at org.springframework.boot.context.config.ConfigDataLoaders.load(ConfigDataLoaders.java:107)
	at org.springframework.boot.context.config.ConfigDataImporter.load(ConfigDataImporter.java:128)
	... 23 common frames omitted
Caused by: com.ecwid.consul.transport.TransportException: java.net.UnknownHostException: https: nodename nor servname provided, or not known
	at com.ecwid.consul.transport.AbstractHttpTransport.executeRequest(AbstractHttpTransport.java:83)
	at com.ecwid.consul.transport.AbstractHttpTransport.makeGetRequest(AbstractHttpTransport.java:36)
	at com.ecwid.consul.v1.ConsulRawClient.makeGetRequest(ConsulRawClient.java:139)
	at com.ecwid.consul.v1.ConsulRawClient.makeGetRequest(ConsulRawClient.java:128)
	at com.ecwid.consul.v1.kv.KeyValueConsulClient.getKVValues(KeyValueConsulClient.java:147)
	at com.ecwid.consul.v1.ConsulClient.getKVValues(ConsulClient.java:644)
	at org.springframework.cloud.consul.config.ConsulPropertySource.init(ConsulPropertySource.java:70)
	at org.springframework.cloud.consul.config.ConsulPropertySources.create(ConsulPropertySources.java:155)
	at org.springframework.cloud.consul.config.ConsulPropertySources.createPropertySource(ConsulPropertySources.java:134)
	... 28 common frames omitted
Caused by: java.net.UnknownHostException: https: nodename nor servname provided, or not known
	at java.base/java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
	at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:933)
	at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1519)
	at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:852)
	at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1509)
	at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1367)
	at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1301)
	at org.apache.http.impl.conn.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:45)
	at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:112)
	at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:376)
	at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:393)
	at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
	at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
	at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
	at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
	at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:221)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:165)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:140)
	at com.ecwid.consul.transport.AbstractHttpTransport.executeRequest(AbstractHttpTransport.java:70)
	... 36 common frames omitted