This guide covers Temporal's archiving capabilities and how to setup the Archival feature.
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.
- 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.
Archival consists of the following elements:
- Configuration: Archival is controlled by the server configuration (i.e. the
- 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.
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.
Archival configuration is defined in the
config/development.yaml file. Let's look at an example configuration below:
You can disable Archival by setting
The following table showcases acceptable values for each configuration and what purpose they serve.
|Must be |
|Must be |
|Sub provider configs are ||Default config specifies |
|File permission string||File permissions of the archived files. We recommend using the default value of |
|File permission string||Directory permissions of the archive directory. We recommend using the default value of |
|Default state of the Archival feature whenever a new Namespace is created without specifying the Archival state.|
|Valid URI||Must be a URI of the file store location and match a schema that correlates to a provider.|
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
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.
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.
You can retrieve archived Event Histories by copying the
runId of the completed Workflow from the log output and running:
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.
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:
The objects should live in
Update provider to enable access to your implementation by modifying the
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.
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:
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.