[1.13] Add docs for SQLite name resolver

[ItalyPaleAle]

Fixes #3914

[hhunter-ms]

quick review

[msfussell]

@ItalyPaleAle @hhunter-ms

To help with this PR (given this is the first time we have updated name resolution in a while) there are a few other topics that need updating along with this PR.

1. Update the configuration overview https://docs.dapr.io/operations/configuration/configuration-overview/ to include how to set the name resolution config as you have in the Configuration format section of the component in this PR. This

• Add it as a linked heading here https://docs.dapr.io/operations/configuration/configuration-overview/#sidecar-configuration-settings and then add a section with this info, but also say that consul is an example.

Configuration format

Within the Configuration YAML, set the spec.nameResolution.component property to "sqlite", then pass configuration options in the spec.nameResolution.configuration dictionary.

This is the basic example of a Configuration resource:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "sqlite"
    version: "v1"
    configuration:
      connectionString: "/home/user/.dapr/nr.db"

2. Update the Configuration resource spec https://docs.dapr.io/reference/resource-specs/configuration-schema/ to include name resolution settings above.

3. Add a link to the https://docs.dapr.io/reference/components-reference/supported-name-resolution/ topic so that users understand how to set name resolution. In effect add this

Name resolution is configured via the [Dapr Configuration]({{< ref configuration-overview.md >}}).

4. Update the "Pluggable service discovery" section https://docs.dapr.io/developing-applications/building-blocks/service-invocation/service-invocation-overview/#pluggable-service-discovery to include this sentence below after this sentence "Self-hosted machines can use the mDNS name resolution component. " like this

"Self-hosted machines can use the mDNS name resolution component. As an alternative to mDNS, the SQLite name resolution component can be used for running Dapr on single-node environments and for local development scenarios. Dapr sidecars that are part of the cluster store their information in a SQLite database on the local machine."

5. Remove "provider spec" in the headings for K8s, Hashicorp and mDNS components. For example here https://docs.dapr.io/reference/components-reference/supported-name-resolution/setup-nr-consul/, here https://docs.dapr.io/reference/components-reference/supported-name-resolution/nr-kubernetes/ and here https://docs.dapr.io/reference/components-reference/supported-name-resolution/nr-mdns/

[msfussell]

Great update. I also left additional comments on Name Resolution above ^^

[msfussell]

Is this table created automatically by Dapr, or do you need to create this in advance?

[ItalyPaleAle]

Everything is automatic

[msfussell]

How does this relate to the timeout above? They sound like they do the same thing. When would I set this over using timeout above. Would be great to have some guidance here in the doc

[ItalyPaleAle]

There's some overlap, but they behave differently.

• busy timeout controls how locking works in SQLite. With SQLite, writes are exclusive, so every time any app is writing something, the DB is locked. If another app tries to write, it will wait up to "busy timeout" before returning the "database busy" error
• the timeout option controls the timeout for the entire operation. For example if the query "hangs", after the DB has acquired the lock (so after busy timeout is cleared), then timeout comes into effect

For SQLite, most users should not touch this

[hhunter-ms]

To help with this PR (given this is the first time we have updated name resolution in a while) there are a few other topics that need updating along with this PR.

@msfussell @ItalyPaleAle I can do this in a separate PR

[msfussell]

LGTM. I did some additional editing to add clarifications on usage

[ItalyPaleAle]

I don't think we need to explain this (and especially I wasn't thinking my words would be used in the docs, or I'd have written something better :) ). I'd just say "This is an advanced setting"

Suggested change

| `busyTimeout` | N | [Go duration](https://pkg.go.dev/time#ParseDuration) (as a `string`) | Interval to wait in case the SQLite database is currently busy serving another request, before returning a "database busy" error. This is an advanced setting.</br>`busyTimeout` controls how locking works in SQLite. With SQLite, writes are exclusive, so every time any app is writing the database is locked. If another app tries to write, it waits up to `busyTimeout` before returning the "database busy" error. However the `timeout` setting controls the timeout for the entire operation. For example if the query "hangs", after the database has acquired the lock (so after busy timeout is cleared), then `timeout` comes into effect. Default: `800ms` (800 milliseconds) | `"100ms"` |

| `busyTimeout` | N | [Go duration](https://pkg.go.dev/time#ParseDuration) (as a `string`) | Interval to wait in case the SQLite database is currently busy serving another request, before returning a "database busy" error.<br>This is an advanced setting that controls how long to wait if the database is locked by another transaction.<br>Default: `800ms` (800 milliseconds) | `"100ms"` |

[hhunter-ms]

some clarification and fixing typos