EyeCueLab's kit
is a repository of open-source golang libraries developed by EyeCueLab for use in our various projects.
EyeCueLab tries to follow the philosphy of the twelve-factor app. All non-business logic should be open & accessible to the public, and configuration details should be in the environment.
Accordingly, EyeCueLab uses the cobra command-line interface and the viper configuration library. Many parts of kit
either rely on these libraries for configuration or hook into them during init() so that cobra/viper can access them.
Navigate to the root of the source directory for kit
go test ./... -cover
address
contains tools for storing and comparing street addreses.
(TODO)
brake
contains tools for setting up and working with the airbrake error monitoring software.
(TODO)
cmd
contains helper fucntions for the cobra command-line interface
coerce
contains functions which use reflection to coerce various numeric types using c-style numeric promotion. This is mostly for testing.
config
contains helper functions to help set up viper configuration library
counter
implements various counter types, similar to python's collections.counter
db
contains tools for various databases. See db/mongo
or db/psql
.
db/mongo
helps connect to our mongoDB instances and provides various helper functions
db/psql
helps connect to psql instances and provides various helper functions
(TODO)
env
contains tools for accessing and manipulating environment variables
errorlib
contains tools to deal with errors, including the heavily-used ErrorString
type (for errors that are compile-time constants) and LoggedChannel
function (to report non-fatal errors during concurrent execution)
flect
is meant to work alongside go's reflect
library, containing additional runtime reflection tools
geojson
contains an interface and various structs for 2d and 3d geometry that correspond to the geojson format.
(TODO)
imath
is contains tools for signed integer math. it largely corresponds with go's built in math
library for float64s
imath/operator
contains functions which represent all of golang's built in operators,as well as bitwise operators
log
is an extension of the logrus package. It contains various tools for logging information and errors during runtime.
(TODO)
maputil
contains various helper functions for maps with string keys.
the maputil package itself covers map[string]interface{}
maputil
contains helper functions for the type map[string]string
(TODO)
pretty
provides pretty-printing for go values. It is a fork of the kr/pretty package, obtained under the MIT license.
random
provides tools for generating cryptographically secure random elements. it uses golang's built in crypto/rand
for it's RNG.
random/shuffle
provides tools for creating shuffled copies of various golang slice types using the fisher-yates shuffle. It uses crypto/rand
for it's RNG.
(TODO)
runeset
implements a set of runes and various methods for dealing with strings accordingly. it should probably be folded into the set
package.
s3
contains helper functions for dealing with amazon's aws/s3 and integrating it with the cobra CLI.
set
implements various set types and associated methods; union, intersection, containment, etc. see runeset
for a set of runes (this will be folded into set.)
str
contains various tools for manipulation of strings beyond those available in golang's strings
library. it also contains a wide variety of string constants.
stringslice
contains various functions to work with slices of strings and the strings contained within.
set/int
implements a set type for int
set/string
implements a set type for string
sortlib
contains tools for producing sorted copies of various golang types
tickertape
provides an implenetation of a concurrency-safe 'ticker tape' of current information during a running program - that is, repeatedly updating the same line with new information.
tsv
contains tools for dealing with tab-separated values.
umath
contains various math functions for unsigned integers, roughly corresponding with imath
and golang's built in math
package.
web
is the bones of our web framework, built on top of google's jsonapi framework and labstack's echo framework.
(TODO)
(TODO)
(TODO)
(TODO)
A serializer/deserializer for JSON payloads that comply to the JSON API - jsonapi.org spec in go.
go get -u github.com/google/jsonapi
Or, see Alternative Installation.
You are working in your Go web application and you have a struct that is
organized similarly to your database schema. You need to send and
receive json payloads that adhere to the JSON API spec. Once you realize that
your json needed to take on this special form, you go down the path of
creating more structs to be able to serialize and deserialize JSON API
payloads. Then there are more models required with this additional
structure. Ugh! With JSON API, you can keep your model structs as is and
use StructTags to indicate
to JSON API how you want your response built or your request
deserialized. What about your relationships? JSON API supports
relationships out of the box and will even put them in your response
into an included
side-loaded slice--that contains associated records.
JSON API uses StructField tags to annotate the structs fields that you already have and use in your app and then reads and writes JSON API output based on the instructions you give the library in your JSON API tags. Let's take an example. In your app, you most likely have structs that look similar to these:
type Blog struct {
ID int `json:"id"`
Title string `json:"title"`
Posts []*Post `json:"posts"`
CurrentPost *Post `json:"current_post"`
CurrentPostId int `json:"current_post_id"`
CreatedAt time.Time `json:"created_at"`
ViewCount int `json:"view_count"`
}
type Post struct {
ID int `json:"id"`
BlogID int `json:"blog_id"`
Title string `json:"title"`
Body string `json:"body"`
Comments []*Comment `json:"comments"`
}
type Comment struct {
Id int `json:"id"`
PostID int `json:"post_id"`
Body string `json:"body"`
Likes uint `json:"likes_count,omitempty"`
}
These structs may or may not resemble the layout of your database. But these are the ones that you want to use right? You wouldn't want to use structs like those that JSON API sends because it is difficult to get at all of your data easily.
This program demonstrates the implementation of a create, a show, and a list http.Handler. It outputs some example requests and responses as well as serialized examples of the source/target structs to json. That is to say, I show you that the library has successfully taken your JSON API request and turned it into your struct types.
To run,
- Make sure you have Go installed
- Create the following directories or similar:
~/go
- Set
GOPATH
toPWD
in your shell session,export GOPATH=$PWD
go get github.com/google/jsonapi
. (Append-u
afterget
if you are updating.)cd $GOPATH/src/github.com/google/jsonapi/examples
go build && ./examples
The jsonapi
StructTags
tells this library how to marshal and unmarshal your structs into
JSON API payloads and your JSON API payloads to structs, respectively.
Then Use JSON API's Marshal and Unmarshal methods to construct and read
your responses and replies. Here's an example of the structs above
using JSON API tags:
type Blog struct {
ID int `jsonapi:"primary,blogs"`
Title string `jsonapi:"attr,title"`
Posts []*Post `jsonapi:"relation,posts"`
CurrentPost *Post `jsonapi:"relation,current_post"`
CurrentPostID int `jsonapi:"attr,current_post_id"`
CreatedAt time.Time `jsonapi:"attr,created_at"`
ViewCount int `jsonapi:"attr,view_count"`
}
type Post struct {
ID int `jsonapi:"primary,posts"`
BlogID int `jsonapi:"attr,blog_id"`
Title string `jsonapi:"attr,title"`
Body string `jsonapi:"attr,body"`
Comments []*Comment `jsonapi:"relation,comments"`
}
type Comment struct {
ID int `jsonapi:"primary,comments"`
PostID int `jsonapi:"attr,post_id"`
Body string `jsonapi:"attr,body"`
Likes uint `jsonapi:"attr,likes-count,omitempty"`
}
`jsonapi:"primary,<type field output>"`
This indicates this is the primary key field for this struct type.
Tag value arguments are comma separated. The first argument must be,
primary
, and the second must be the name that should appear in the
type
* field for all data objects that represent this type of model.
* According the JSON API spec, the plural record types are shown in the examples, but not required.
`jsonapi:"attr,<key name in attributes hash>,<optional: omitempty>"`
These fields' values will end up in the attributes
hash for a record.
The first argument must be, attr
, and the second should be the name
for the key to display in the attributes
hash for that record. The optional
third argument is omitempty
- if it is present the field will not be present
in the "attributes"
if the field's value is equivalent to the field types
empty value (ie if the count
field is of type int
, omitempty
will omit the
field when count
has a value of 0
). Lastly, the spec indicates that
attributes
key names should be dasherized for multiple word field names.
`jsonapi:"relation,<key name in relationships hash>,<optional: omitempty>"`
Relations are struct fields that represent a one-to-one or one-to-many
relationship with other structs. JSON API will traverse the graph of
relationships and marshal or unmarshal records. The first argument must
be, relation
, and the second should be the name of the relationship,
used as the key in the relationships
hash for the record. The optional
third argument is omitempty
- if present will prevent non existent to-one and
to-many from being serialized.
All Marshal
and Unmarshal
methods expect pointers to struct
instance or slices of the same contained with the interface{}
s
Now you have your structs prepared to be seralized or materialized, What about the rest?
You can Unmarshal a JSON API payload using jsonapi.UnmarshalPayload. It reads from an io.Reader containing a JSON API payload for one record (but can have related records). Then, it materializes a struct that you created and passed in (using new or &). Again, the method supports single records only, at the top level, in request payloads at the moment. Bulk creates and updates are not supported yet.
After saving your record, you can use, MarshalOnePayload, to write the JSON API response to an io.Writer.
UnmarshalPayload(in io.Reader, model interface{})
Visit godoc
MarshalPayload(w io.Writer, models interface{}) error
Visit godoc
Writes a JSON API response, with related records sideloaded, into an
included
array. This method encodes a response for either a single record or
many records.
func CreateBlog(w http.ResponseWriter, r *http.Request) {
blog := new(Blog)
if err := jsonapi.UnmarshalPayload(r.Body, blog); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// ...save your blog...
w.Header().Set("Content-Type", jsonapi.MediaType)
w.WriteHeader(http.StatusCreated)
if err := jsonapi.MarshalPayload(w, blog); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
UnmarshalManyPayload(in io.Reader, t reflect.Type) ([]interface{}, error)
Visit godoc
Takes an io.Reader
and a reflect.Type
representing the uniform type
contained within the "data"
JSON API member.
func CreateBlogs(w http.ResponseWriter, r *http.Request) {
// ...create many blogs at once
blogs, err := UnmarshalManyPayload(r.Body, reflect.TypeOf(new(Blog)))
if err != nil {
t.Fatal(err)
}
for _, blog := range blogs {
b, ok := blog.(*Blog)
// ...save each of your blogs
}
w.Header().Set("Content-Type", jsonapi.MediaType)
w.WriteHeader(http.StatusCreated)
if err := jsonapi.MarshalPayload(w, blogs); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
If you need to include link objects along with response data, implement the Linkable
interface for document-links, and RelationshipLinkable
for relationship links:
func (post Post) JSONAPILinks() *Links {
return &Links{
"self": "href": fmt.Sprintf("https://example.com/posts/%d", post.ID),
"comments": Link{
Href: fmt.Sprintf("https://example.com/api/blogs/%d/comments", post.ID),
Meta: map[string]interface{}{
"counts": map[string]uint{
"likes": 4,
},
},
},
}
}
// Invoked for each relationship defined on the Post struct when marshaled
func (post Post) JSONAPIRelationshipLinks(relation string) *Links {
if relation == "comments" {
return &Links{
"related": fmt.Sprintf("https://example.com/posts/%d/comments", post.ID),
}
}
return nil
}
If you need to include meta objects along with response data, implement the Metable
interface for document-meta, and RelationshipMetable
for relationship meta:
func (post Post) JSONAPIMeta() *Meta {
return &Meta{
"details": "sample details here",
}
}
// Invoked for each relationship defined on the Post struct when marshaled
func (post Post) JSONAPIRelationshipMeta(relation string) *Meta {
if relation == "comments" {
return &Meta{
"this": map[string]interface{}{
"can": map[string]interface{}{
"go": []interface{}{
"as",
"deep",
map[string]interface{}{
"as": "required",
},
},
},
},
}
}
return nil
}
This package also implements support for JSON API compatible errors
payloads using the following types.
MarshalErrors(w io.Writer, errs []*ErrorObject) error
Writes a JSON API response using the given []error
.
type ErrorsPayload struct {
Errors []*ErrorObject `json:"errors"`
}
ErrorsPayload is a serializer struct for representing a valid JSON API errors payload.
type ErrorObject struct { ... }
// Error implements the `Error` interface.
func (e *ErrorObject) Error() string {
return fmt.Sprintf("Error: %s %s\n", e.Title, e.Detail)
}
ErrorObject is an Error
implementation as well as an implementation of the JSON API error object.
The main idea behind this struct is that you can use it directly in your code as an error type and pass it directly to MarshalErrors
to get a valid JSON API errors payload.
// An error has come up in your code, so set an appropriate status, and serialize the error.
if err := validate(&myStructToValidate); err != nil {
context.SetStatusCode(http.StatusBadRequest) // Or however you need to set a status.
jsonapi.MarshalErrors(w, []*ErrorObject{{
Title: "Validation Error",
Detail: "Given request body was invalid.",
Status: "400",
Meta: map[string]interface{}{"field": "some_field", "error": "bad type", "expected": "string", "received": "float64"},
}})
return
}
MarshalOnePayloadEmbedded(w io.Writer, model interface{}) error
Visit godoc
This method is not strictly meant to for use in implementation code,
although feel free. It was mainly created for use in tests; in most cases,
your request payloads for create will be embedded rather than sideloaded
for related records. This method will serialize a single struct pointer
into an embedded json response. In other words, there will be no,
included
, array in the json; all relationships will be serialized
inline with the data.
However, in tests, you may want to construct payloads to post to create methods that are embedded to most closely model the payloads that will be produced by the client. This method aims to enable that.
out := bytes.NewBuffer(nil)
// testModel returns a pointer to a Blog
jsonapi.MarshalOnePayloadEmbedded(out, testModel())
h := new(BlogsHandler)
w := httptest.NewRecorder()
r, _ := http.NewRequest(http.MethodPost, "/blogs", out)
h.CreateBlog(w, r)
blog := new(Blog)
jsonapi.UnmarshalPayload(w.Body, blog)
// ... assert stuff about blog here ...
I use git subtrees to manage dependencies rather than go get
so that
the src is committed to my repo.
git subtree add --squash --prefix=src/github.com/google/jsonapi https://github.com/google/jsonapi.git master
To update,
git subtree pull --squash --prefix=src/github.com/google/jsonapi https://github.com/google/jsonapi.git master
This assumes that I have my repo structured with a src
dir containing
a collection of packages and GOPATH
is set to the root
folder--containing src
.
Fork, Change, Pull Request with tests.