blob

Blob is a Go library that provides a unified interface for creating object storage buckets across multiple cloud providers. It parses a connection string URL, automatically determines the storage driver, and returns a ready-to-use objstore.Bucket backed by thanos-io/objstore.

Installation

go get github.com/corticph/gocomo/blob

Quick Start

1. Set the Connection String

The bucket is configured via the BLOB_STORAGE_CONNECTION_STRING environment variable.

S3:

s3://<access_key>:<secret_key>@<endpoint>/<bucket>?region=us-east-1

Azure:

azure://<client_id>:<client_secret>@<account_name>.blob.core.windows.net/<container>?az_tenant_id=<tenant-id>

Credentials are optional — if omitted, the provider falls back to its default credential chain (environment variables, config files, IAM, etc.).

2. Create a Bucket

import (
    "log/slog"
    "os"
    "github.com/corticph/gocomo/blob"
)

logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
bkt, err := blob.NewBucket(logger)
if err != nil {
    log.Fatalf("Failed to create bucket: %v", err)
}
defer bkt.Close()

3. Upload and Download Objects

ctx := context.Background()

// Upload
if err := bkt.Upload(ctx, "my-object.txt", strings.NewReader("hello world")); err != nil {
    log.Fatalf("Upload failed: %v", err)
}

// Download
rc, err := bkt.Get(ctx, "my-object.txt")
if err != nil {
    log.Fatalf("Get failed: %v", err)
}
defer rc.Close()

data, _ := io.ReadAll(rc)
fmt.Println(string(data))

// Delete
if err := bkt.Delete(ctx, "my-object.txt"); err != nil {
    log.Fatalf("Delete failed: %v", err)
}

Connection String Format

The connection string is a standard URL where the scheme selects the storage driver, the host and path provide driver-specific routing, and query parameters map to provider config fields.

S3

s3://[<access_key>:<secret_key>@]<endpoint>/<bucket>?key=value

When no userinfo is provided, the S3 provider falls back to the default credential chain (environment variables, ~/.aws/credentials, IAM).

Azure

azure://[<client_id>:<client_secret>@]<account_name>.blob.core.windows.net/<container>?key=value

Authentication priority:

1. storage_account_key query param — shared key auth
2. client_id + client_secret (userinfo) + az_tenant_id (query param) — client secret auth
3. Neither — DefaultAzureCredential from the Azure identity SDK

For Azurite (local development), use storage_connection_string as a query param since the host has no subdomain:

azure://localhost:10000/devstoreaccount1/my-container?storage_connection_string=...

Query Parameters

Query parameters map directly to the underlying provider config fields. Nested fields use dot notation:

?http_config.insecure_skip_verify=true&http_config.max_idle_conns=250

Boolean values (true/false) and integers are automatically coerced. Strings with leading zeros are preserved as strings to avoid corrupting identifiers.

Supported Providers