/
s3.go
126 lines (109 loc) · 2.71 KB
/
s3.go
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package ginS3
import (
"fmt"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
"github.com/aws/aws-sdk-go/aws/ec2metadata"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/s3"
"github.com/aws/aws-sdk-go/service/s3/s3manager"
"github.com/gin-gonic/gin"
)
func checkExistingBucket(c *s3.S3, bucket string) error {
output, err := c.ListBuckets(&s3.ListBucketsInput{})
if err != nil {
panic(err)
}
for _, b := range output.Buckets {
if bucket == *b.Name {
return nil
}
}
return fmt.Errorf("failed to find bucket %s", bucket)
}
// NewDefault instanciates a new S3 handler with the default S3 client
func NewDefault(bucket string, modifiers ...buildFunc) gin.HandlerFunc {
s, err := session.NewSession()
if err != nil {
panic(err)
}
b := builder{
region: "eu-west-1",
credentialProviders: []credentials.Provider{},
config: aws.NewConfig(),
}
for _, f := range modifiers {
b = f(b)
}
if b.config.Credentials == nil {
if len(b.credentialProviders) == 0 {
b.credentialProviders = []credentials.Provider{
&credentials.EnvProvider{},
&credentials.SharedCredentialsProvider{},
&ec2rolecreds.EC2RoleProvider{
Client: ec2metadata.New(s),
},
}
}
creds := credentials.NewChainCredentials(b.credentialProviders)
b.config.WithCredentials(creds)
}
if b.config.Region == nil {
region, err := s3manager.GetBucketRegion(aws.BackgroundContext(), s, bucket, b.region)
if err != nil {
panic(err)
}
b.config.WithRegion(region)
}
c := s3.New(s, b.config)
err = checkExistingBucket(c, bucket)
if err != nil {
panic(err)
}
handler := &S3{
Client: c,
Bucket: bucket,
Logger: b.logger,
}
return handler.Handle
}
type buildFunc func(builder) builder
type builder struct {
credentialProviders []credentials.Provider
region string
logger Logger
config *aws.Config
}
// AddProvider adds a credential provider to the s3 client
func AddProvider(provider credentials.Provider) buildFunc {
return func(b builder) builder {
r := b
r.credentialProviders = append(r.credentialProviders, provider)
return r
}
}
// WithLogger sets the logger for the handler
func WithLogger(logger Logger) buildFunc {
return func(b builder) builder {
r := b
r.logger = logger
return r
}
}
// WithRegion sets the default s3 region
func WithRegion(region string) buildFunc {
return func(b builder) builder {
r := b
r.region = region
return r
}
}
// WithConfig sets the s3 endpoint
func WithConfig(config *aws.Config) buildFunc {
return func(b builder) builder {
r := b
r.config = config
return r
}
}