Support Azure reload in case the file is changing

README.md

@@ -84,3 +84,27 @@ To upload your files to AWS S3 you will need an IAM policy for writing/reading t
         ]
     }
 
+## Azure Specific Dev Notes
+Run a local blobstore emulator:
+```shell
+podman run -p 10000:10000 -v .:/log  mcr.microsoft.com/azure-storage/azurite \ 
+    azurite-blob --debug /log/debug.log 
+```
+Azurite accepts the same well-known account and key used by the legacy Azure Storage Emulator.
+
+- Account name: `devstoreaccount1`
+- Account key: `Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==`
+
+Uploading files:
+```sh
+export AZURE_STORAGE_CONNECTION_STRING="DefaultEndpointsProtocol=http;AccountName=devstoreaccount1;AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;BlobEndpoint=http://127.0.0.1:10000/devstoreaccount1;QueueEndpoint=http://127.0.0.1:10001/devstoreaccount1;TableEndpoint=http://127.0.0.1:10002/devstoreaccount1;"
+az storage  container create --name data       
+az storage blob upload --file a1.pmtiles --container-name data --name a.pmtiles    
+az storage blob upload --overwrite  --file a2.pmtiles --container-name data --name a.pmtiles    
+```
+
+
+Starting pmtiles:
+```sh
+AZURE_STORAGE_ACCOUNT=devstoreaccount1 AZURE_STORAGE_KEY="Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==" ./go-pmtiles serve --port=8084 / --bucket="azblob://data?protocol=http&domain=127.0.0.1:10000"
+```

pmtiles/bucket.go

@@ -15,6 +15,8 @@
 	"path/filepath"
 	"strings"
 
+	"github.com/Azure/azure-sdk-for-go/sdk/azcore"
+	azblobblob "github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/blob"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/service/s3"
 	"github.com/cespare/xxhash/v2"
@@ -48,8 +50,8 @@
 func (m mockBucket) NewRangeReader(ctx context.Context, key string, offset int64, length int64) (io.ReadCloser, error) {
 	body, _, _, err := m.NewRangeReaderEtag(ctx, key, offset, length, "")
 	return body, err
-
 }
+
 func (m mockBucket) NewRangeReaderEtag(_ context.Context, key string, offset int64, length int64, etag string) (io.ReadCloser, string, int, error) {
 	bs, ok := m.items[key]
 	if !ok {
@@ -111,7 +113,7 @@
 	return hasherToEtag(hasher)
 }
 
 func (b FileBucket) NewRangeReaderEtag(_ context.Context, key string, offset, length int64, etag string) (io.ReadCloser, string, int, error) {
 	name := filepath.Join(b.path, key)
 	file, err := os.Open(name)
 	defer file.Close()
@@ -144,7 +146,7 @@
 	return io.NopCloser(bytes.NewReader(result)), newEtag, 206, nil
 }
 
 func (b FileBucket) Close() error {
 	return nil
 }
 
@@ -202,16 +204,16 @@
 	return code == http.StatusPreconditionFailed || code == http.StatusRequestedRangeNotSatisfiable
 }
 
-type BucketAdapter struct {
+type S3BucketAdapter struct {
 	Bucket *blob.Bucket
 }
 
-func (ba BucketAdapter) NewRangeReader(ctx context.Context, key string, offset, length int64) (io.ReadCloser, error) {
+func (ba S3BucketAdapter) NewRangeReader(ctx context.Context, key string, offset, length int64) (io.ReadCloser, error) {
 	body, _, _, err := ba.NewRangeReaderEtag(ctx, key, offset, length, "")
 	return body, err
 }
 
-func (ba BucketAdapter) NewRangeReaderEtag(ctx context.Context, key string, offset, length int64, etag string) (io.ReadCloser, string, int, error) {
+func (ba S3BucketAdapter) NewRangeReaderEtag(ctx context.Context, key string, offset, length int64, etag string) (io.ReadCloser, string, int, error) {
 	reader, err := ba.Bucket.NewRangeReader(ctx, key, offset, length, &blob.ReaderOptions{
 		BeforeRead: func(asFunc func(interface{}) bool) error {
 			var req *s3.GetObjectInput
@@ -242,7 +244,59 @@
 	return reader, resultETag, status, nil
 }
 
-func (ba BucketAdapter) Close() error {
+func (ba S3BucketAdapter) Close() error {
+	return ba.Bucket.Close()
+}
+
+type AzureBucketAdapter struct {
+	Bucket *blob.Bucket
+}
+
+func (ba AzureBucketAdapter) NewRangeReader(ctx context.Context, key string, offset, length int64) (io.ReadCloser, error) {
+	body, _, _, err := ba.NewRangeReaderEtag(ctx, key, offset, length, "")
+	return body, err
+}
+
+func (ba AzureBucketAdapter) NewRangeReaderEtag(ctx context.Context, key string, offset, length int64, etag string) (io.ReadCloser, string, int, error) {
+	reader, err := ba.Bucket.NewRangeReader(ctx, key, offset, length, &blob.ReaderOptions{
+		BeforeRead: func(asFunc func(interface{}) bool) error {
+			var req *azblobblob.DownloadStreamOptions
+			if len(etag) > 0 && asFunc(&req) {
+				etag := azcore.ETag(etag)
+				if req.AccessConditions == nil {
+					req.AccessConditions = &azblobblob.AccessConditions{}
+				}
+				if req.AccessConditions.ModifiedAccessConditions == nil {
+					req.AccessConditions.ModifiedAccessConditions = &azblobblob.ModifiedAccessConditions{}
+				}
+				req.AccessConditions.ModifiedAccessConditions.IfMatch = &etag
+			}
+			return nil
+		},
+	})
+	status := 206
+	if err != nil {
+		var resp *azcore.ResponseError
+		errors.As(err, &resp)
+		status = 404
+		if resp != nil {
+			status = resp.StatusCode
+			if isRefreshRequiredCode(resp.StatusCode) {
+				return nil, "", resp.StatusCode, &RefreshRequiredError{resp.StatusCode}
+			}
+		}
+		return nil, "", status, err
+	}
+	resultETag := ""
+	var resp azblobblob.DownloadStreamResponse
+	if reader.As(&resp) {
+		resultETag = string(*resp.ETag)
+	}
+
+	return reader, resultETag, status, nil
+}
+
+func (ba AzureBucketAdapter) Close() error {
 	return ba.Bucket.Close()
 }
 
@@ -293,13 +347,18 @@
 		bucket := NewFileBucket(filepath.FromSlash(path))
 		return bucket, nil
 	}
+
 	bucket, err := blob.OpenBucket(ctx, bucketURL)
 	if err != nil {
 		return nil, err
 	}
 	if bucketPrefix != "" && bucketPrefix != "/" && bucketPrefix != "." {
 		bucket = blob.PrefixedBucket(bucket, path.Clean(bucketPrefix)+string(os.PathSeparator))
 	}
-	wrappedBucket := BucketAdapter{bucket}
+	if strings.HasPrefix(bucketURL, "azblob") {
+		bucket := AzureBucketAdapter{bucket}
+		return bucket, nil
+	}
+	wrappedBucket := S3BucketAdapter{bucket}
 	return wrappedBucket, err
 }