interfaces 
Code generation tools for Go's interfaces.
Tools available in this repository:
cmd/interfacer 
Generates an interface for a named type.
Installation
~ $ go get github.com/rjeczalik/interfaces/cmd/interfacer
Usage
~ $ interfacer -help
Usage of interfacer:
-all
Include also unexported methods.
-as string
Generated interface name. (default "main.Interface")
-for string
Type to generate an interface for.
-o string
Output file. (default "-")
Example
- generate by manually
~ $ interfacer -for os.File -as mock.File
- generate by go generate
//go:generate interfacer -for os.File -as mock.File -o file_iface.go
~ $ go generate ./...
- output
// Created by interfacer; DO NOT EDIT
package mock
import (
"os"
)
// File is an interface generated for "os".File.
type File interface {
Chdir() error
Chmod(os.FileMode) error
Chown(int, int) error
Close() error
Fd() uintptr
Name() string
Read([]byte) (int, error)
ReadAt([]byte, int64) (int, error)
Readdir(int) ([]os.FileInfo, error)
Readdirnames(int) ([]string, error)
Seek(int64, int) (int64, error)
Stat() (os.FileInfo, error)
Sync() error
Truncate(int64) error
Write([]byte) (int, error)
WriteAt([]byte, int64) (int, error)
WriteString(string) (int, error)
}
cmd/structer 
Generates a struct for a formatted file. Currently supported formats are:
- CSV
Installation
~ $ go get github.com/rjeczalik/interfaces/cmd/structer
Usage
~ $ structer -help
Usage of structer:
-as string
Generated struct name. (default "main.Struct")
-f string
Input file. (default "-")
-o string
Output file. (default "-")
-tag string
Name for a struct tag to add to each field.
-type string
Type of the input, overwrites inferred from file name.
Example
~ $ head -2 aws-billing.csv # first line is a CSV header, second - first line of values
"InvoiceID","PayerAccountId","LinkedAccountId","RecordType","RecordID","BillingPeriodStartDate","BillingPeriodEndDate","InvoiceDate"
"Estimated","123456","","PayerLineItem","5433212345","2016/01/01 00:00:00","2016/01/31 23:59:59","2016/01/21 19:19:06"
~ $ structer -f aws-billing.csv -tag json -as billing.Record
// Created by structer; DO NOT EDIT
package billing
import (
"strconv"
"time"
)
// Record is a struct generated from "aws-billing.csv" file.
type Record struct {
InvoiceID string `json:"invoiceID"`
PayerAccountID int64 `json:"payerAccountID"`
LinkedAccountID string `json:"linkedAccountID"`
RecordType string `json:"recordType"`
RecordID int64 `json:"recordID"`
BillingPeriodStartDate time.Time `json:"billingPeriodStartDate"`
BillingPeriodEndDate time.Time `json:"billingPeriodEndDate"`
InvoiceDate time.Time `json:"invoiceDate"`
}
// MarshalCSV encodes r as a single CSV record.
func (r *Record) MarshalCSV() ([]string, error) {
records := []string{
r.InvoiceID,
strconv.FormatInt(r.PayerAccountID, 10),
r.LinkedAccountID,
r.RecordType,
strconv.FormatInt(r.RecordID, 10),
time.Parse("2006/01/02 15:04:05", r.BillingPeriodStartDate),
time.Parse("2006/01/02 15:04:05", r.BillingPeriodEndDate),
time.Parse("2006/01/02 15:04:05", r.InvoiceDate),
}
return records, nil
}
// UnmarshalCSV decodes a single CSV record into r.
func (r *Record) UnmarshalCSV(record []string) error {
if len(record) != 8 {
return fmt.Errorf("invalud number fields: want 8, got %d", len(record))
}
r.InvoiceID = record[0]
if record[1] != "" {
if val, err := strconv.ParseInt(record[1], 10, 64); err == nil {
r.PayerAccountID = val
} else {
return err
}
}
r.LinkedAccountID = record[2]
r.RecordType = record[3]
if record[4] != "" {
if val, err := strconv.ParseInt(record[4], 10, 64); err == nil {
r.RecordID = val
} else {
return err
}
}
if record[5] != "" {
if val, err := time.Parse("2006/01/02 15:04:05", record[5]); err == nil {
r.BillingPeriodStartDate = val
} else {
return err
}
}
if record[6] != "" {
if val, err := time.Parse("2006/01/02 15:04:05", record[6]); err == nil {
r.BillingPeriodEndDate = val
} else {
return err
}
}
if record[7] != "" {
if val, err := time.Parse("2006/01/02 15:04:05", record[7]); err == nil {
r.InvoiceDate = val
} else {
return err
}
}
return nil
}