Archive Workflow data
This guide covers Temporal's archiving capabilities and how to setup the Archival feature.
Overview
Temporal stores data that is generated from a Workflow, such as Event Histories, per the configured retention period. When the retention period expires the data is deleted to avoid running out of space. To preserve Workflow data indefinitely you can use the Archival feature, which automatically moves the data from Temporal persistence to long-term storage (i.e. S3) after the Workflow retention period expires.
There are at least two reasons you may want to keep data after the retention period has passed:
- Compliance: For legal reasons, data may need to be stored for a long period of time.
- Debugging: Older data may help with debugging.
note
- Archival is not supported when running Temporal via docker-compose.
- Archival is disabled by default when installing the system manually and when deploying via helm charts, but can be enabled in the config.
- Archival only supports Event Histories. You may notice some boilerplate infrastructure to support archiving visibility records. Visibility archival is not yet supported and visibility records are deleted after the Workflow retention period.
Setup
Archival consists of the following elements:
- Configuration: Archival is controlled by the server configuration (i.e. the
config/development.yaml
file). - Provider: Location where the data should be archived. Supported providers are S3, GCloud, and the local file system.
- URI: Specifies which provider should be used. The system uses the URI schema and path to make the determination.
Take the following steps to set up Archival:
- Set up the provider of your choice.
- Configure Archival.
- Create a Namespace that uses a valid URI and has Archival enabled.
Providers
Temporal supports several providers out of the box:
- Local file system: The filestore archiver is used to archive data in the file system of whatever host the Temporal server is running on. This provider is used mainly for local installations and testing and should not be relied on for production environments.
- Google Cloud: The gcloud archiver is used to connect and archive data with Google Cloud.
- S3: The s3store archiver is used to connect and archive data with S3.
- Custom: If you want to use a provider that is not currently supported, you can create your own archiver to support it.
Make sure that you save the provider's storage location URI in a place where you can reference it later, as it is passed as a parameter when you create a Namespace.
Configuration
Archival configuration is defined in the config/development.yaml
file. Let's look at an example configuration below:
You can disable Archival by setting archival.history.state
and namespaceDefaults.archival.history.state
to "disabled"
.
Example:
The following table showcases acceptable values for each configuration and what purpose they serve.
Config | Acceptable values | Description |
---|---|---|
archival.history.state | enabled , disabled | Must be enabled to use the Archival feature with any Namespace in the cluster. |
archival.history.enableRead | true , false | Must be true to read from the archived Event History. |
archival.history.provider | Sub provider configs are filestore , gstorage , s3 , or your_custom_provider . | Default config specifies filestore . |
archival.history.provider.filestore.fileMode | File permission string | File permissions of the archived files. We recommend using the default value of "0666" to avoid read/write issues. |
archival.history.provider.filestore.dirMode | File permission string | Directory permissions of the archive directory. We recommend using the default value of "0766" to avoid read/write issues. |
namespaceDefaults.archival.history.state | enabled , disabled | Default state of the Archival feature whenever a new Namespace is created without specifying the Archival state. |
namespaceDefaults.archival.history.URI | Valid URI | Must be a URI of the file store location and match a schema that correlates to a provider. |
Namespace creation
While Archival is configured at the cluster level, it operates independently within each Namespace. When a Namespace is created, if an Archival URI is not specified then the Namespace will use the value of defaultNamespace.archival.history.URI
from the config/development.yaml
file. The Archival URI can not be changed once the Namespace is created. Each Namespace supports just a single Archival URI, but each Namespace can use a different URI. A Namespace can safely switch Archival between enabled
and disabled
states as long as Archival is enabled at the cluster level.
Archival is supported in global Namespaces (Namespaces spanning multiple clusters). When Archival is running in a global Namepsace, it will first run on the active cluster and then some time later it will run on the standby cluster. Before archiving, a history check is done to see what has been previously archived.
Test setup
To test Archival locally, start by running a Temporal server:
Then register a new Namespace with Archival enabled.
Next, run a sample Workflow such as the helloworld temporal sample.
Once execution has finished Archival will occur.
Retrieve archives
You can retrieve archived Event Histories by copying the workflowId
and runId
of the completed Workflow from the log output and running:
Custom archiver
To archive data with a given provider, Temporal must have a corresponding archiver component installed. The system does not intend to limit you to the existing providers, so to use a provider that is not currently supported you may create your own archiver.
Create a new package
The first step is to create a new package for your implementation in /common/archiver. Create a new directory in the archiver folder and arrange the structure to look like the following:
Archiver interfaces
Next, define objects that implement the HistoryArchiver and the VisibilityArchiver interfaces.
The objects should live in historyArchiver.go
and visibilityArchiver.go
respectively.
Update provider
Update provider to enable access to your implementation by modifying the
Update the GetHistoryArchiver
and GetVisibilityArchiver
methods of the archiverProvider
object in the /common/archiver/provider/provider.go file so that it knows how to create an instance of your archiver.
Add configs
Add configs for you archiver to the config/development.yaml
file and then modify the HistoryArchiverProvider and VisibilityArchiverProvider struct in /common/service/config.go
accordingly.
Custom archiver FAQ
If my custom Archive method can automatically be retried by the caller, how can I record and access progress between retries?
Handle this using the ArchiverOptions
. Here is an example:
If my Archive
method encounters an error which is non-retryable how do I indicate to the caller that should not retry?
How does my history archiver implementation read history?
The archiver package provides a utility called HistoryIterator which is a wrapper of HistoryManager. HistoryIterator
is more simple than the HistoryManager
, which is available in the BootstrapContainer, so archiver implementations can choose to use it when reading Workflow histories. See the historyIterator.go file for more details. Use the filestore historyArchiver implementation as an example.
Should my archiver define its own error types?
Each archiver is free to define and return its own errors. However many common errors which exist between archivers are already defined in common/archiver/constants.go.
Is there a generic query syntax for the visibility archiver?
Currently no. But this is something we plan to do in the future. As for now, try to make your syntax similar to the one used by our advanced list Workflow API.