generationtux/brizo

package jsonutil

import (
    "encoding/json"
    "net/http"
)

// SelfRespondingJSONError is an interfaces representing the ability to render
// its own contents.
type SelfRespondingJSONError interface {
    // Render will write the contents of the JSON error to the provided
    // http.ResponseWriter
    Render(w http.ResponseWriter)
}

// GenericSelfRespondingJSONError is a generic implementation of of the
// SelfRespondingJSONError interface. This is good to use when there is little
// to no logic in defining error messages or status codes.
type GenericSelfRespondingJSONError struct {
    // Details is a human readable message that describes the error.
    Details string `json:"details,omitempty"`
    // Status is appropriate the HTTP status code for the error.
    Status int `json:"status,string"`
}

// Render writes the contents of the GenericSelfRespondingJSONError to the
// provided http.ResponseWriter.
func (srje *GenericSelfRespondingJSONError) Render(w http.ResponseWriter) {
    w.Header().Set("content-type", "application/json")
    w.WriteHeader(srje.Status)
    payload, _ := json.Marshal(srje)
    w.Write(payload)
}

// DatabaseConnectError is a wrapper for a new GenericSelfRespondingJSONError
// that will provide a predefined message for a database connection error. It
// returns a SelfRespondingJSONError, in the form of a
// GenericSelfRespondingJSONError, so that rendering can be chained.
//
// Example:
//   DatabaseConnectError().Render(w)
func DatabaseConnectError() SelfRespondingJSONError {
    return &GenericSelfRespondingJSONError{
        Details: "there was an error when attempting to connect to the database",
        Status:  http.StatusInternalServerError,
    }
}

// KubeClientConnectionError provides a predefined message for a Kubernetes
// client connection error. Rendering can be chained.
func KubeClientConnectionError() SelfRespondingJSONError {
    return &GenericSelfRespondingJSONError{
        Details: "unable to reach Kubernetes",
        Status:  http.StatusServiceUnavailable,
    }
}