Auto Auth Healing for Proxy

[divyaac]

Auto Auth will self heal if Proxy is using an auto auth token that is bogus, has reached max uses, or max ttl.

Approved Ent Pr: https://github.com/hashicorp/vault-enterprise/pull/5672

closes : https://github.com/hashicorp/vault-enterprise/pull/5672

[github-actions]

CI Results:
All Go tests succeeded! ✅

[github-actions]

Build Results:
All builds succeeded! ✅

[VioletHynes]

There are some test failures due to a panic:

2024-04-08T21:57:39.940Z [INFO]  agent.apiproxy: http: panic serving 127.0.0.1:34436: interface conversion: interface is nil, not sink.SinkReader
goroutine 10762 [running]:
net/http.(*conn).serve.func1()
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:1868 +0xff
panic({0xe60d380?, 0xc0050dea80?})
	/opt/hostedtoolcache/go/1.21.8/x64/src/runtime/panic.go:920 +0x270
github.com/hashicorp/vault/command.(*AgentCommand).Run.ProxyHandler.func15({0x1273ad20?, 0xc004877a40}, 0xc005dade00)
	/home/runner/work/vault/vault/command/agentproxyshared/cache/handler.go:39 +0x354
net/http.HandlerFunc.ServeHTTP(0xc005806b40, {0x1273ad20, 0xc004877a40}, 0xc0047e8c40?)
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:2136 +0x48
net/http.(*ServeMux).ServeHTTP(0x0?, {0x1273ad20, 0xc004877a40}, 0xc005dade00)
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:2514 +0xbd
net/http.serverHandler.ServeHTTP({0xc0050de9c0?}, {0x1273ad20, 0xc004877a40}, 0xc005dade00)
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:2938 +0x2a2
net/http.(*conn).serve(0xc0059baea0, {0x1275a060, 0xc00548b800})
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:2009 +0xc25
created by net/http.(*Server).Serve in goroutine 10783
	/opt/hostedtoolcache/go/1.21.8/x64/src/net/http/server.go:3086 +0x86d
    agent_test.go:2271: default expectError=false error=Get "http://127.0.0.1:46727/v1/secret/foo": EOF secret=<nil>

[VioletHynes]

Looks great, but I'll hold off approving until we figure out the test failures. Once we've addressed them, feel free to re-request me :D