options pattern

chiv.go

@@ -1,10 +1,81 @@
+// Package chiv archives arbitrarily large relational database tables to Amazon S3.
 package chiv
 
 import (
+ "context"
+ "database/sql"
+
  "github.com/aws/aws-sdk-go/service/s3/s3manager"
 )
 
-func Archive(uploader *s3manager.Uploader) {
+type Archiver struct {
+ db *sql.DB
+ s3 *s3manager.Uploader
+ format Format // TODO WithFormat(Format) Option
+ // TODO other options like batch size... in bytes or rows?
+}
+
+type Option func(*Archiver)
+
+type Format int
+
+const (
+ CSV Format = iota
+ JSON
+)
+
+const (
+ DefaultFormat = CSV
+)
+
+// NewArchiver constructs an Archiver with the given database connection, S3 uploader and options.
+func NewArchiver(db *sql.DB, s3 *s3manager.Uploader, options ...Option) *Archiver {
+ a := Archiver{
+ db: db,
+ s3: s3,
+ format: DefaultFormat,
+ }
+
+ for _, option := range options {
+ option(&a)
+ }
+
+ return &a
+}
+
+// Archive a database table to S3.
+func (a *Archiver) Archive(table string, options ...Option) error {
+ return a.ArchiveWithContext(context.Background(), table, options...)
+}
+
+// Archive a database table to S3 with context.
+func (a *Archiver) ArchiveWithContext(ctx context.Context, table string, options ...Option) error {
+ archiver := archiver{
+ db: a.db, // TODO do these need to be top level or use archiver.config.db and archiver.config.s3?
+ s3: a.s3,
+ ctx: ctx,
+ config: a,
+ }
+
+ for _, option := range options {
+ option(archiver.config)
+ }
+
+ return archiver.archive(table)
+}
+
+type archiver struct {
+ db *sql.DB
+ s3 *s3manager.Uploader
+ ctx context.Context
+ config *Archiver
+}
+
+func (a *archiver) archive(table string) error {
+
+ // TODO the work
+ // db cursor selecting: ???
+ // s3 streaming: https://docs.aws.amazon.com/code-samples/latest/catalog/go-s3-upload_arbitrary_sized_stream.go.html
 
- //https://docs.aws.amazon.com/code-samples/latest/catalog/go-s3-upload_arbitrary_sized_stream.go.html
+ return nil // TODO return size or some other info along w/ error?
 }

chiv_test.go

@@ -1,3 +1,5 @@
+// Package chiv_test includes integration tests external to package chiv
+// and relies on external services postgres and s3 (localstack) via CodeShip.
 package chiv_test
 
 import (
@@ -9,4 +11,4 @@ import (
 func TestArchive(t *testing.T) {
  chiv.Archive()
  t.Log("test test test")
-}
+}