AppendBlobService Class
An append blob is comprised of blocks and is optimized for append operations. When you modify an append blob, blocks are added to the end of the blob only, via the append_block operation. Updating or deleting of existing blocks is not supported. Unlike a block blob, an append blob does not expose its block IDs.
Each block in an append blob can be a different size, up to a maximum of 4 MB, and an append blob can include up to 50,000 blocks. The maximum size of an append blob is therefore slightly more than 195 GB (4 MB X 50,000 blocks).
- Inheritance
-
AppendBlobService
Constructor
AppendBlobService(account_name=None, account_key=None, sas_token=None, is_emulated=False, protocol='https', endpoint_suffix='core.windows.net', custom_domain=None, request_session=None, connection_string=None, socket_timeout=None, token_credential=None)Parameters
- account_name
- account_key
- sas_token
- is_emulated
- protocol
- endpoint_suffix
- custom_domain
- request_session
- connection_string
- socket_timeout
- token_credential
Variables
- MAX_BLOCK_SIZE
- int
The size of the blocks put by append_blob_from_* methods. Smaller blocks may be put if there is less data provided. The maximum block size the service supports is 4MB.
Methods
| append_blob_from_bytes |
Appends to the content of an existing blob from an array of bytes, with automatic chunking and progress notifications. |
| append_blob_from_path |
Appends to the content of an existing blob from a file path, with automatic chunking and progress notifications. |
| append_blob_from_stream |
Appends to the content of an existing blob from a file/stream, with automatic chunking and progress notifications. |
| append_blob_from_text |
Appends to the content of an existing blob from str/unicode, with automatic chunking and progress notifications. |
| append_block |
Commits a new block of data to the end of an existing append blob. |
| create_blob |
Creates a blob or overrides an existing blob. Use if_none_match=* to prevent overriding an existing blob. See create_blob_from_* for high level functions that handle the creation and upload of large blobs with automatic chunking and progress notifications. |
append_blob_from_bytes
Appends to the content of an existing blob from an array of bytes, with automatic chunking and progress notifications.
append_blob_from_bytes(container_name, blob_name, blob, index=0, count=None, validate_content=False, maxsize_condition=None, progress_callback=None, lease_id=None, timeout=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None)Parameters
- count
- int
Number of bytes to upload. Set to None or negative value to upload all bytes starting from index.
- validate_content
- bool
If true, calculates an MD5 hash for each chunk of the blob. The storage service checks the hash of the content that has arrived with the hash that was sent. This is primarily valuable for detecting bitflips on the wire if using http instead of https as https (the default) will already validate. Note that this MD5 hash is not stored with the blob.
- maxsize_condition
- int
Optional conditional header. The max length in bytes permitted for the append blob. If the Append Block operation would cause the blob to exceed that limit or if the blob size is already greater than the value specified in this header, the request will fail with MaxBlobSizeConditionNotMet error (HTTP status code 412 - Precondition Failed).
- progress_callback
- <xref:func>(<xref:current>, <xref:total>)
Callback for progress with signature function(current, total) where current is the number of bytes transfered so far, and total is the size of the blob, or None if the total size is unknown.
- timeout
- int
The timeout parameter is expressed in seconds. This method may make multiple calls to the Azure service and the timeout will apply to each call individually.
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag and last modified properties for the Append Blob
Return type
append_blob_from_path
Appends to the content of an existing blob from a file path, with automatic chunking and progress notifications.
append_blob_from_path(container_name, blob_name, file_path, validate_content=False, maxsize_condition=None, progress_callback=None, lease_id=None, timeout=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None)Parameters
- validate_content
- bool
If true, calculates an MD5 hash for each chunk of the blob. The storage service checks the hash of the content that has arrived with the hash that was sent. This is primarily valuable for detecting bitflips on the wire if using http instead of https as https (the default) will already validate. Note that this MD5 hash is not stored with the blob.
- maxsize_condition
- int
Optional conditional header. The max length in bytes permitted for the append blob. If the Append Block operation would cause the blob to exceed that limit or if the blob size is already greater than the value specified in this header, the request will fail with MaxBlobSizeConditionNotMet error (HTTP status code 412 - Precondition Failed).
- progress_callback
- <xref:func>(<xref:current>, <xref:total>)
Callback for progress with signature function(current, total) where current is the number of bytes transfered so far, and total is the size of the blob, or None if the total size is unknown.
- timeout
- int
The timeout parameter is expressed in seconds. This method may make multiple calls to the Azure service and the timeout will apply to each call individually.
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag and last modified properties for the Append Blob
Return type
append_blob_from_stream
Appends to the content of an existing blob from a file/stream, with automatic chunking and progress notifications.
append_blob_from_stream(container_name, blob_name, stream, count=None, validate_content=False, maxsize_condition=None, progress_callback=None, lease_id=None, timeout=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None)Parameters
- count
- int
Number of bytes to read from the stream. This is optional, but should be supplied for optimal performance.
- validate_content
- bool
If true, calculates an MD5 hash for each chunk of the blob. The storage service checks the hash of the content that has arrived with the hash that was sent. This is primarily valuable for detecting bitflips on the wire if using http instead of https as https (the default) will already validate. Note that this MD5 hash is not stored with the blob.
- maxsize_condition
- int
Conditional header. The max length in bytes permitted for the append blob. If the Append Block operation would cause the blob to exceed that limit or if the blob size is already greater than the value specified in this header, the request will fail with MaxBlobSizeConditionNotMet error (HTTP status code 412 - Precondition Failed).
- progress_callback
- <xref:func>(<xref:current>, <xref:total>)
Callback for progress with signature function(current, total) where current is the number of bytes transfered so far, and total is the size of the blob, or None if the total size is unknown.
- timeout
- int
The timeout parameter is expressed in seconds. This method may make multiple calls to the Azure service and the timeout will apply to each call individually.
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag and last modified properties for the Append Blob
Return type
append_blob_from_text
Appends to the content of an existing blob from str/unicode, with automatic chunking and progress notifications.
append_blob_from_text(container_name, blob_name, text, encoding='utf-8', validate_content=False, maxsize_condition=None, progress_callback=None, lease_id=None, timeout=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None)Parameters
- validate_content
- bool
If true, calculates an MD5 hash for each chunk of the blob. The storage service checks the hash of the content that has arrived with the hash that was sent. This is primarily valuable for detecting bitflips on the wire if using http instead of https as https (the default) will already validate. Note that this MD5 hash is not stored with the blob.
- maxsize_condition
- int
Optional conditional header. The max length in bytes permitted for the append blob. If the Append Block operation would cause the blob to exceed that limit or if the blob size is already greater than the value specified in this header, the request will fail with MaxBlobSizeConditionNotMet error (HTTP status code 412 - Precondition Failed).
- progress_callback
- <xref:func>(<xref:current>, <xref:total>)
Callback for progress with signature function(current, total) where current is the number of bytes transfered so far, and total is the size of the blob, or None if the total size is unknown.
- timeout
- int
The timeout parameter is expressed in seconds. This method may make multiple calls to the Azure service and the timeout will apply to each call individually.
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetime will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag and last modified properties for the Append Blob
Return type
append_block
Commits a new block of data to the end of an existing append blob.
append_block(container_name, blob_name, block, validate_content=False, maxsize_condition=None, appendpos_condition=None, lease_id=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None, timeout=None)Parameters
- validate_content
- bool
If true, calculates an MD5 hash of the block content. The storage service checks the hash of the content that has arrived with the hash that was sent. This is primarily valuable for detecting bitflips on the wire if using http instead of https as https (the default) will already validate. Note that this MD5 hash is not stored with the blob.
- maxsize_condition
- int
Optional conditional header. The max length in bytes permitted for the append blob. If the Append Block operation would cause the blob to exceed that limit or if the blob size is already greater than the value specified in this header, the request will fail with MaxBlobSizeConditionNotMet error (HTTP status code 412 - Precondition Failed).
- appendpos_condition
- int
Optional conditional header, used only for the Append Block operation. A number indicating the byte offset to compare. Append Block will succeed only if the append position is equal to this number. If it is not, the request will fail with the AppendPositionConditionNotMet error (HTTP status code 412 - Precondition Failed).
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetimes will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetimes will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag, last modified, append offset, and committed block count properties for the updated Append Blob
Return type
create_blob
Creates a blob or overrides an existing blob. Use if_none_match=* to prevent overriding an existing blob.
See create_blob_from_* for high level functions that handle the creation and upload of large blobs with automatic chunking and progress notifications.
create_blob(container_name, blob_name, content_settings=None, metadata=None, lease_id=None, if_modified_since=None, if_unmodified_since=None, if_match=None, if_none_match=None, timeout=None)Parameters
- content_settings
- ContentSettings
ContentSettings object used to set blob properties.
- if_modified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetimes will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has been modified since the specified time.
- if_unmodified_since
- datetime
A DateTime value. Azure expects the date value passed in to be UTC. If timezone is included, any non-UTC datetimes will be converted to UTC. If a date is passed in without timezone info, it is assumed to be UTC. Specify this header to perform the operation only if the resource has not been modified since the specified date/time.
- if_match
- str
An ETag value, or the wildcard character (*). Specify this header to perform the operation only if the resource's ETag matches the value specified.
- if_none_match
- str
An ETag value, or the wildcard character (). Specify this header to perform the operation only if the resource's ETag does not match the value specified. Specify the wildcard character () to perform the operation only if the resource does not exist, and fail the operation if it does exist.
Returns
ETag and last modified properties for the updated Append Blob
Return type
Attributes
MAX_BLOCK_SIZE
MAX_BLOCK_SIZE = 4194304Feedback
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