Function for customizing http.Transport for a http/2 client

[cubicdaiya]

Now buford provides the function of push.NewClient(cert tls.Certifcate) (*http.Client, error) for creating a http/2 client.

client, err := push.NewClient(certificate)

But push.NewClient() can not customize http.Transport like the code below for a http/2 client.

// example definition
transport := &http.Transport{
        TLSClientConfig:     config,
        MaxIdleConnsPerHost: 16,
}

MaxIdleConnsPerHost is important for sending many notifications to APNs once. Accoding to the document below (Best Practices for Managing Connections), increasing connections to APNs seems to be recommended for improving performance. (MaxIdleConnsPerHost is 2 by default. )

https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/APNsProviderAPI.html#//apple_ref/doc/uid/TP40008194-CH101-SW1

Though it is good if there is the function for customizing http.Transport for a http/2 client, what do you think?

[nathany]

Thanks for mentioning the MaxIdleConnsPerHost consideration.

I'm not sure that it's really necessary to add a function for Buford to customize transport, or what it would look like if I did. You can easily copy/paste and modify these 10 lines of code to create your own HTTP client that you pass to push.NewService.

// NewClient sets up an HTTP/2 client for a certificate.
func NewClient(cert tls.Certificate) (*http.Client, error) {
    config := &tls.Config{
        Certificates: []tls.Certificate{cert},
    }
    config.BuildNameToCertificate()
    transport := &http.Transport{TLSClientConfig: config}

    if err := http2.ConfigureTransport(transport); err != nil {
        return nil, err
    }

    return &http.Client{Transport: transport}, nil
}

(from https://github.com/RobotsAndPencils/buford/blob/master/push/service.go#L43)

FYI, the NewClient function and certificate loading may eventually all go away with #63, though not in the immediate future.

[cubicdaiya]

Thank you for the reply and suggestion.