Logs emitted by a database plugin(v4) is not shown in Vault logs under `info` level.

[sebinjohn]

Describe the bug

Logs emitted by a database plugin(v4) is not shown in Vault logs under info level.

To Reproduce

• Clone https://github.com/sebinjohn/vault-plugin-database-mockdb.git

Test - 1

1. Terminal 1: make start-vault LOG_LEVEL=info
2. Terminal 2: make dev-flow
3. Check for the string " plugin-mockdb: the type is MOCK" in the vault logs in Terminal 1
4. Terminal 1: Kill the running vault

Test - 2

1. Terminal 1: make start-vault LOG_LEVEL=debug
2. Terminal 2: make dev-flow
3. Check for the string " plugin-mockdb: the type is MOCK" in the vault logs in Terminal 1

Expected behavior In both test cases, the logs should show the string plugin-mockdb: the type is MOCK. But it is visible only when vault log level is set to DEBUG.

Environment:

• Vault Server Version (retrieve with vault status):

  
  % vault status
  Key             Value
  ---             -----
  Seal Type       shamir
  Initialized     true
  Sealed          false
  Total Shares    1
  Threshold       1
  Version         1.8.1
  Storage Type    inmem
  Cluster Name    vault-cluster-f0938d13
  Cluster ID      cc1f4a74-4e49-8ed7-258c-e4cf7d498fe3
  HA Enabled      false

* Vault CLI Version (retrieve with `vault version`):

% vault --version Vault v1.8.1 ('4b0264f28defc05454c31277cfa6ff63695a458d+CHANGES')

* Server Operating System/Architecture: Darwin/Amd64

Vault server configuration file(s): This is reproducible in dev server 

**Additonal Context**

The readme at https://github.com/hashicorp/go-plugin/tree/master/ says

> Built-in Logging. Any plugins that use the log standard library will have log data automatically sent to the host process. The host process will mirror this output prefixed with the path to the plugin binary. This makes debugging with plugins simple. If the host system uses hclog then the log data will be structured. If the plugin also uses hclog, logs from the plugin will be sent to the host hclog and be structured.

The issue is faced in our production environment but to reproduce the issue I'm using a mock database plugin 
This is a v4 plugin and I'm not sure if the issue will occur with v5. The issue is reproducible with dev servers.

[ncabatoff]

Hi @sebinjohn,

Thanks for filing this issue.

There are always going to be differences of opinion as to what the appropriate severity for a given log line ought to be, e.g. some will find it infuriating that message X isn't visible at INFO, whereas others would find their INFO logs too noisy if X were included.

Because it's so situational, we generally don't accept requests to change log levels unless there's a really compelling argument. There are alternatives to get lower severity logs without changing the system log level for everything, e.g. you can use vault monitor or sys/loggers.