refactor: move things around to make building a client easier from other projects (#123)

* refactor: split logic for building API config into public func
* refactor: move config code out of internal/

api/configuration_default.go

@@ -0,0 +1,44 @@
+package api
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/http"
+	"net/url"
+)
+
+type ConfigParams struct {
+	Host             *url.URL
+	UserAgent        string
+	Token            *string
+	TraceId          *string
+	AllowInsecureTLS bool
+	Debug            bool
+}
+
+// NewAPIConfig builds a configuration tailored to the InfluxDB v2 API.
+func NewAPIConfig(params ConfigParams) *Configuration {
+	clientTransport := http.DefaultTransport.(*http.Transport).Clone()
+	clientTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: params.AllowInsecureTLS}
+
+	apiConfig := NewConfiguration()
+	apiConfig.Host = params.Host.Host
+	apiConfig.Scheme = params.Host.Scheme
+	apiConfig.UserAgent = params.UserAgent
+	apiConfig.HTTPClient = &http.Client{Transport: clientTransport}
+	if params.Token != nil {
+		apiConfig.DefaultHeader["Authorization"] = fmt.Sprintf("Token %s", *params.Token)
+	}
+	if params.TraceId != nil {
+		// NOTE: This is circumventing our codegen. If the header we use for tracing ever changes,
+		// we'll need to manually update the string here to match.
+		//
+		// The alternative is to pass the trace ID to the business logic for every CLI command, and
+		// use codegen'd logic to set the header on every HTTP request. Early versions of the CLI
+		// used that technique, and we found it to be error-prone and easy to forget during testing.
+		apiConfig.DefaultHeader["Zap-Trace-Span"] = *params.TraceId
+	}
+	apiConfig.Debug = params.Debug
+
+	return apiConfig
+}