Skills

Chapter 12 of 28

Encore Go Bucket

Store unstructured files in Encore Go using objects.NewBucket from encore.dev/storage/objects — uploads, images, documents, blobs.

1 minute · 113 words · 6 sections

Encore Go Object Storage

Instructions

A Bucket is a logical store for files. Encore provisions the underlying object storage (S3 on AWS, GCS on GCP, in-memory locally). Declare buckets as package-level variables.

package uploads

import "encore.dev/storage/objects"

// Private bucket (default)
var Uploads = objects.NewBucket("user-uploads", objects.BucketConfig{})

// Public bucket — files accessible via public URL
var PublicAssets = objects.NewBucket("public-assets", objects.BucketConfig{
    Public: true,
})

Operations

import (
    "fmt"
    "io"
)

// Upload (streaming pattern)
writer := Uploads.Upload(ctx, "path/to/file.jpg")
_, err := io.Copy(writer, dataReader)
if err != nil {
    writer.Abort()
    return err
}
err = writer.Close()

// Download
reader := Uploads.Download(ctx, "path/to/file.jpg")
if err := reader.Err(); err != nil {
    return err
}
defer reader.Close()
data, _ := io.ReadAll(reader)

// Existence check
exists, err := Uploads.Exists(ctx, "path/to/file.jpg")

// Attributes (size, content type, ETag)
attrs, err := Uploads.Attrs(ctx, "path/to/file.jpg")

// List
for err, entry := range Uploads.List(ctx, &objects.Query{}) {
    if err != nil {
        return err
    }
    fmt.Println(entry.Key, entry.Size)
}

// Delete
err := Uploads.Remove(ctx, "path/to/file.jpg")

// Public URL (only for public buckets)
url := PublicAssets.PublicURL("image.jpg")

Signed URLs

Generate temporary URLs so clients can upload/download directly without going through your service:

import "time"

// Signed upload URL (expires in 2 hours)
url, err := Uploads.SignedUploadURL(ctx, "user-uploads/avatar.jpg",
    objects.WithTTL(time.Duration(7200)*time.Second))

// Signed download URL
url, err := Uploads.SignedDownloadURL(ctx, "documents/report.pdf",
    objects.WithTTL(time.Duration(7200)*time.Second))

Bucket References

Pass bucket access to library code with a specific permission set:

// Create a reference with download permission only
ref := objects.BucketRef[objects.Downloader](Uploads)

// Combine permissions via an interface
type myPerms interface {
    objects.Downloader
    objects.Uploader
}
ref := objects.BucketRef[myPerms](Uploads)

// Permission types: Downloader, Uploader, Lister, Attrser, Remover,
// SignedDownloader, SignedUploader, ReadWriter

Guidelines

Declare buckets as package-level variables.
Default to private buckets; opt into Public: true only for assets meant for unauthenticated download.
Use signed URLs for browser uploads/downloads instead of streaming through your service.
Use bucket references when passing access to helpers — they encode the permission contract in the type system.

Install this repository

$ npx skills add encoredev/skills

» /plugin marketplace add encoredev/skills

Skills install per repository, not per chapter — the CLI has no documented per-skill form, so we do not print one.

About this skill

Trigger

Store unstructured files in Encore Go using `objects.NewBucket` from `encore.dev/storage/objects` — uploads, images, documents, blobs.

The verbatim description from this skill’s front matter — the string an agent matches on to decide whether to load it.

Colophon for this issue

Colophon

How this issue was made

Source

github.com/encoredev/skills, branch main, last pushed 15 May 2026.

Licence

Apache-2.0 — the text of every chapter is reproduced unmodified, frontmatter included, under the upstream licence.

Discovery

28 chapters found by walking the repository tree for SKILL.md, not by matching a directory convention. One layout observed: encore/*/SKILL.md.

Issue colours

Resolved from a deterministic hash of the owner name. Two accent tones are generated per issue and each is proven against its own ground before it ships: a single accent that passes AA on both light and dark paper is arithmetically impossible.

Heading repairs

1 repair applied to this chapter so the document has one h1 and no skipped levels:

Shifted “6 headings” from h1 to h2 so the chapter title is the only h1.

Spec compliance

28 editorial notes across 28 of 28 chapters. They are printed in the margin of each chapter rather than as errors here.

Encore API — 1 note
Encore Auth — 1 note
Encore Bucket — 1 note
Encore Cache — 1 note
Encore Code Review — 1 note
Encore Cron — 1 note
Encore Database — 1 note
Encore Frontend — 1 note
Encore Getting Started — 1 note
Encore Go API — 1 note

and 18 more.

Images

Images inside a chapter come from the upstream repository. Where the author gave no alternative text we mark the image decorative rather than inventing a description — a plausible caption we made up is worse than none for the reader who depends on it.

Marketplace

A plugin manifest is published at .claude-plugin/marketplace.json by Encore, declaring 1 plugin. It is read for editorial metadata only — never as the skill index, which is always the repository tree.

Signal

Install counts come from skills.sh. They measure downloads, not quality, and an unranked repository is not an unread one.

Agent surfaces

The whole issue is available as one markdown document at /encoredev/skills.md, and each chapter at its own .md URL.

Publication

Set by Skills Docs from the source repository. Body text is Literata at the reader’s chosen size and measure; code is Geist Mono. Nothing on this page was written by us except this paragraph.

Encore Go Object Storage

A Bucket is a logical store for files. Encore provisions the underlying object storage (S3 on AWS, GCS on GCP, in-memory locally). Declare buckets as package-level variables.

package uploads

import "encore.dev/storage/objects"

// Private bucket (default)
var Uploads = objects.NewBucket("user-uploads", objects.BucketConfig{})

// Public bucket — files accessible via public URL
var PublicAssets = objects.NewBucket("public-assets", objects.BucketConfig{
    Public: true,
})

import (
    "fmt"
    "io"
)

// Upload (streaming pattern)
writer := Uploads.Upload(ctx, "path/to/file.jpg")
_, err := io.Copy(writer, dataReader)
if err != nil {
    writer.Abort()
    return err
}
err = writer.Close()

// Download
reader := Uploads.Download(ctx, "path/to/file.jpg")
if err := reader.Err(); err != nil {
    return err
}
defer reader.Close()
data, _ := io.ReadAll(reader)

// Existence check
exists, err := Uploads.Exists(ctx, "path/to/file.jpg")

// Attributes (size, content type, ETag)
attrs, err := Uploads.Attrs(ctx, "path/to/file.jpg")

// List
for err, entry := range Uploads.List(ctx, &objects.Query{}) {
    if err != nil {
        return err
    }
    fmt.Println(entry.Key, entry.Size)
}

// Delete
err := Uploads.Remove(ctx, "path/to/file.jpg")

// Public URL (only for public buckets)
url := PublicAssets.PublicURL("image.jpg")

Generate temporary URLs so clients can upload/download directly without going through your service:

import "time"

// Signed upload URL (expires in 2 hours)
url, err := Uploads.SignedUploadURL(ctx, "user-uploads/avatar.jpg",
    objects.WithTTL(time.Duration(7200)*time.Second))

// Signed download URL
url, err := Uploads.SignedDownloadURL(ctx, "documents/report.pdf",
    objects.WithTTL(time.Duration(7200)*time.Second))

Pass bucket access to library code with a specific permission set:

// Create a reference with download permission only
ref := objects.BucketRef[objects.Downloader](Uploads)

// Combine permissions via an interface
type myPerms interface {
    objects.Downloader
    objects.Uploader
}
ref := objects.BucketRef[myPerms](Uploads)

// Permission types: Downloader, Uploader, Lister, Attrser, Remover,
// SignedDownloader, SignedUploader, ReadWriter

Declare buckets as package-level variables.

Default to private buckets; opt into Public: true only for assets meant for unauthenticated download.

Use signed URLs for browser uploads/downloads instead of streaming through your service.

Use bucket references when passing access to helpers — they encode the permission contract in the type system.