Merge pull request #5 from wormhole-foundation/ilariae/spies

Ilariae/spies

Author: eshaben

learn/infrastructure/.pages

@@ -3,3 +3,4 @@ nav:
  - index.md
  - 'VAAs': 'vaas.md'
  - 'Guardians': 'guardians.md'
+ - 'Spies': 'spy.md'

learn/infrastructure/spy.md

@@ -0,0 +1,70 @@
+---
+title: Spy
+description: Discover Wormhole's Spy daemon, which subscribes to gossiped messages in the Guardian Network, including VAAs and Observations, with setup instructions.
+---
+
+# Spy
+
+In the Wormhole context, a _Spy_ is a daemon that subscribes to the gossiped messages in the Guardian Network.
+
+The messages available over gossip are things like:
+
+- [VAAs](#){target=\_blank} <!-- link to VAAs page -->
+- [Observations](#){target=\_blank} <!-- link to glossary -->
+- Guardian heartbeats
+
+The source code for the Spy is available on [GitHub](https://github.com/wormhole-foundation/wormhole/blob/main/node/cmd/spy/spy.go){target=\_blank}.
+
+!!! note
+    The Spy has no persistence layer built in, so typically, it is paired with something like Redis or an SQL database to record relevant messages.
+
+## How to Start a Spy
+
+To start a Spy locally, run the following Docker command:
+
+=== "Testnet"
+
+    ```sh
+    docker run --platform=linux/amd64 \
+        -p 7073:7073 \
+        --entrypoint /guardiand ghcr.io/wormhole-foundation/guardiand:latest \
+        spy \
+        --nodeKey /node.key \
+        --spyRPC "[::]:7073" \
+        --env testnet
+    ```
+        Optionally, add the following flags to skip any VAAs with invalid signatures:
+    ```sh
+    --ethRPC https://sepolia.drpc.org/
+    --ethContract 0x4a8bc80Ed5a4067f1CCf107057b8270E0cC11A78    
+    ```
+
+=== "Mainnet"
+
+    ```sh
+    docker run --platform=linux/amd64 \
+        -p 7073:7073 \
+        --entrypoint /guardiand ghcr.io/wormhole-foundation/guardiand:latest \
+        spy \
+        --nodeKey /node.key \
+        --spyRPC "[::]:7073" \
+        --env mainnet
+    ```
+    Optionally, add the following flags to skip any VAAs with invalid signatures:
+    ```sh
+    --ethRPC https://eth.drpc.org
+    --ethContract 0x98f3c9e6E3fAce36bAAd05FE09d375Ef1464288B
+    ```
+
+Once running, a [gRPC](https://grpc.io/){target=\_blank} client (i.e., your program) can subscribe to a filtered stream of messages.
+
+To generate a client for the gRPC service use [this proto spec file](https://github.com/wormhole-foundation/wormhole/blob/main/proto/spy/v1/spy.proto){target=\_blank}.
+
+!!! note
+    If using JavaScript/TypeScript, the [Spydk](https://www.npmjs.com/package/@certusone/wormhole-spydk){target=\_blank} makes setting up a client easier.
+
+## See Also
+
+The [Pyth Beacon](https://github.com/pyth-network/beacon){target=\_blank} provides an alternate Spy implementation that is highly available for improved performance and reliability.
+
+The [relayer engine](https://github.com/wormhole-foundation/relayer-engine){target=\_blank} implements a client and persistence layer for messages received from a Spy subscription.