2.9 KiB
| type | title | linkTitle | weight | description |
|---|---|---|---|---|
| docs | State Time-to-Live (TTL) | State TTL | 500 | Manage state with time-to-live. |
Introduction
Dapr enables per state set request time-to-live (TTL). This means that applications can set time-to-live per state stored, and these states cannot be retrieved after expiration.
Only a subset of Dapr [state store components]({{< ref supported-state-stores >}}) are compatible with state TTL. For supported state stores simply set the ttlInSeconds metadata when publishing a message. Other state stores will ignore this value.
Some state stores can specify a default expiration on a per-table/container basis. Please refer to the official documentation of these state stores to utilize this feature of desired. Dapr support per-state TTLs for supported state stores.
Native state TTL support
When state time-to-live has native support in the state store component, Dapr simply forwards the time-to-live configuration without adding any extra logic, keeping predictable behavior. This is helpful when the expired state is handled differently by the component. When a TTL is not specified the default behavior of the state store is retained.
Persisting state (ignoring an existing TTL)
To explicitly persist a state (ignoring any TTLs set for the key), specify a ttlInSeconds value of -1.
Supported components
Please refer to the TTL column in the tables at [state store components]({{< ref supported-state-stores >}}).
Example
State TTL can be set in the metadata as part of the state store set request:
{{< tabs Python "HTTP API (Bash)" "HTTP API (PowerShell)">}}
{{% codetab %}}
#dependencies
from dapr.clients import DaprClient
#code
DAPR_STORE_NAME = "statestore"
with DaprClient() as client:
client.save_state(DAPR_STORE_NAME, "order_1", str(orderId), metadata=(
('ttlInSeconds', '120')
))
Once saved run the following command to launch a Dapr sidecar and run the application:
dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 -- python3 OrderProcessingService.py
{{% /codetab %}}
{{% codetab %}}
curl -X POST -H "Content-Type: application/json" -d '[{ "key": "order_1", "value": "250", "metadata": { "ttlInSeconds": "120" } }]' http://localhost:3601/v1.0/state/statestore
{{% /codetab %}}
{{% codetab %}}
Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{"key": "order_1", "value": "250", "metadata": {"ttlInSeconds": "120"}}]' -Uri 'http://localhost:3601/v1.0/state/statestore'
{{% /codetab %}}
{{< /tabs >}}
See [this guide]({{< ref state_api.md >}}) for a reference on the state API.
Related links
- Learn [how to use key value pairs to persist a state]({{< ref howto-get-save-state.md >}})
- List of [state store components]({{< ref supported-state-stores >}})
- Read the [API reference]({{< ref state_api.md >}})