refactor: expose generated code and client business logic to share with Kapacitor (#103)

* refactor: take clients out of internal

* refactor: move stdio to pkg

* Move internal/api to api

* refactor: final changes for Kapacitor to access shared functionality

* chore: regenerate mocks

* fix: bad automated refactor

* chore: extra formatting not caught by make fmt

api/error.go

@@ -0,0 +1,45 @@
+package api
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Extensions to let our API error types be used as "standard" errors.
+
+func (o *Error) Error() string {
+	if o.Message != "" && o.Err != nil {
+		var b strings.Builder
+		b.WriteString(o.Message)
+		b.WriteString(": ")
+		b.WriteString(*o.Err)
+		return b.String()
+	} else if o.Message != "" {
+		return o.Message
+	} else if o.Err != nil {
+		return *o.Err
+	}
+	return fmt.Sprintf("<%s>", o.Code)
+}
+
+func (o *HealthCheck) Error() string {
+	if o.Status == HEALTHCHECKSTATUS_PASS {
+		// Make sure we aren't misusing HealthCheck responses.
+		panic("successful healthcheck used as an error!")
+	}
+	var message string
+	if o.Message != nil {
+		message = *o.Message
+	} else {
+		message = fmt.Sprintf("check %s failed", o.Name)
+	}
+	return fmt.Sprintf("health check failed: %s", message)
+}
+
+func (o *LineProtocolError) Error() string {
+	return o.Message
+}
+
+func (o *LineProtocolLengthError) Error() string {
+	return o.Message
+}