6d4a005e41
This patch adds a `remote` backend for `ext/kv`. This supports connection to Deno Deploy and potentially other services compatible with the KV Connect protocol. |
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| .. | ||
| proto | ||
| 01_db.ts | ||
| build.rs | ||
| Cargo.toml | ||
| codec.rs | ||
| dynamic.rs | ||
| interface.rs | ||
| lib.rs | ||
| README.md | ||
| remote.rs | ||
| sqlite.rs | ||
deno_kv
This crate provides a key/value store for Deno. For an overview of Deno KV, please read the manual.
Storage Backends
Deno KV has a pluggable storage interface that supports multiple backends:
- SQLite - backed by a local SQLite database. This backend is suitable for development and is the default when running locally.
- Remote - backed by a remote service that implements the KV Connect protocol, for example Deno Deploy.
Additional backends can be added by implementing the DatabaseHandler trait.
KV Connect
The KV Connect protocol has separate control and data planes to maximize throughput and minimize latency. Metadata Exchange and Data Path are the two sub-protocols that are used when talking to a KV Connect-compatible service.
Metadata Exchange
To connect to a KV Connect service, the user provides an HTTP or HTTPS URL to
Deno.openKv. A background task is then spawned to periodically make HTTP POST
requests to the provided URL to refresh database metadata.
The HTTP Authorization header is included and have the format
Bearer <access-token>. The <access-token> is a static token issued by the
service provider. For Deno Deploy, this is the personal access token generated
from the dashboard. You can specify the access token with the environment
variable DENO_KV_ACCESS_TOKEN.
Request body is currently unused. The response is a JSON message that satisfies
the JSON Schema definition in
cli/schemas/kv-metadata-exchange-response.v1.json.
Semantics of the response fields:
version: Protocol version. The only supported value is1.databaseId: UUID of the database.endpoints: Data plane endpoints that can serve requests to the database, along with their consistency levels.token: An ephemeral authentication token that must be included in all requests to the data plane. This value is an opaque string and the client should not depend on its format.expiresAt: The time at which the token expires. Encoded as an ISO 8601 string.
Data Path
After the first metadata exchange has completed, the client can talk to the data
plane endpoints listed in the endpoints field using a Protobuf-over-HTTP
protocol called the Data Path. The Protobuf messages are defined in
proto/datapath.proto.
Two sub-endpoints are available under a data plane endpoint URL:
POST /snapshot_read: Used for read operations:kv.get()andkv.getMany().- Request type:
SnapshotRead - Response type:
SnapshotReadOutput
- Request type:
POST /atomic_write: Used for write operations:kv.set()andkv.atomic().commit().- Request type:
AtomicWrite - Response type:
AtomicWriteOutput
- Request type:
An HTTP Authorization header in the format Bearer <ephemeral-token> must be
included in all requests to the data plane. The value of <ephemeral-token> is
the token field from the metadata exchange response.
Error handling
All non-client errors (i.e. network errors and HTTP 5xx status codes) are handled by retrying the request. Randomized exponential backoff is applied to each retry.
Client errors cannot be recovered by retrying. A JavaScript exception is generated for each of those errors.