Better configuration

[sashabaranov]

This PR aims to make the client completely configurable, following up #75 and #4. It also fixes #70.

The idea is to pass-by-value config struct, which would be encapsulated inside the client.

Here we preserve the standard way of creating clients as client := gogpt.NewClient("auth token") and add a new way of configuring clients:

config := DefaultConfig("auth token")
config.BaseURL = server.URL + "/v1"
config.OrgID = "my org id"
config.HTTPClient.Transport = &tokenRoundTripper{
	test.GetTestToken(),
	http.DefaultTransport,
}
config.EmptyMessagesLimit = 10000

client := NewClientWithConfig(config)
ctx := context.Background()

[sashabaranov]

@mwillfox @yangyanqing @DarkDust @ealvar3z @Rascal0814 @RobotSail would love your review!

[DarkDust]

Why is authToken private, but the other fields are public?

[sashabaranov]

Great question! I made it public at first but then figured that I couldn't imagine a case where it needs to be modified or explicitly accessed.

I also thought it would prevent accidental logging, but it seems that it is not the case.

Should I make it public?
🤔 🤔 🤔

[mwillfox]

Just my opinion, but this is how I generally build clients - by allowing any tokens to be passed in at "construction" and then not accessed again. I'm not sure this actually increases security but, like you said, prevents it from being accidentally logged or exposed again. What happens if someone serializes the ClientConfig to JSON? By not exporting the field you prevent that unintentional leak.

[sashabaranov]

@mwillfox btw, it leaks if you do %v printing of the struct

[RobotSail]

LGTM

[mwillfox]

This satisfies my original use case of plugging in retryablehttp as the transport and I agree is a cleaner way of doing config than my original PR. Looks good!

[sashabaranov]

Merged and published in /~https://github.com/sashabaranov/go-gpt3/releases/tag/v1.2.0