chore: setup boilerplate for particle processor worker

This sets up an example of listening to firestore data and reacting. It
also sets up our first worker in the kubernetes cluster.

go/Dockerfile.particleprocessorworker

@@ -0,0 +1,20 @@
+# golang two stage build
+FROM golang:1.25 AS first-stage
+
+WORKDIR /app
+
+COPY go.mod go.sum ./
+RUN go mod download && go mod verify
+
+COPY . .
+
+WORKDIR /app/cmd/particleprocessorworker
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o main
+RUN ls
+
+FROM alpine:latest AS second-stage
+
+WORKDIR /app
+COPY --from=first-stage /app/cmd/particleprocessorworker .
+RUN echo "copied over binary to production stage"
+CMD ["./main"]

go/cmd/particleprocessorworker/main.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"log/slog"
+
+	"github.com/flowy-live/llink/internal/utils"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"cloud.google.com/go/firestore"
+)
+
+func createClient(ctx context.Context) *firestore.Client {
+	projectId := utils.MustGetEnv("GCP_PROJECT")
+
+	client, err := firestore.NewClient(ctx, projectId)
+	if err != nil {
+		log.Fatalf("Failed to create client: %v", err)
+	}
+	return client
+}
+
+// The purpose of the particle processor worker is to listen for new particles
+// across all streams and perform side effects such as
+//   - generate transcript if the particle is of type media
+//   - send mobile notifications if a client is offline
+//   - update the parent stream's `last_child_created_at`
+func main() {
+	ctx := context.Background()
+	client := createClient(ctx)
+	defer client.Close()
+
+	it := client.CollectionGroup("children").Snapshots(ctx)
+	var initialLoad = true
+	for {
+		snap, err := it.Next()
+		if e := status.Code(err); e == codes.DeadlineExceeded || e == codes.Canceled {
+			panic(fmt.Errorf("error: %w", err))
+		}
+		if err != nil {
+			slog.Error("error in processing snapshot", "error", err)
+		}
+
+		if snap != nil {
+			if initialLoad {
+				slog.Info("initial load", "changeCount", len(snap.Changes))
+			} else {
+				for _, change := range snap.Changes {
+					switch change.Kind {
+					case firestore.DocumentAdded:
+						slog.Info("document added: ")
+					case firestore.DocumentModified:
+						slog.Info("document modified")
+					case firestore.DocumentRemoved:
+						slog.Info("document removed")
+					}
+					slog.Info("received document snapshot", "data", change.Doc.Data())
+				}
+			}
+		}
+
+		initialLoad = false
+	}
+}

go/go.mod

@@ -23,7 +23,9 @@ require (
 	cloud.google.com/go/auth v0.17.0 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
 	cloud.google.com/go/compute/metadata v0.9.0 // indirect
+	cloud.google.com/go/firestore v1.21.0 // indirect
 	cloud.google.com/go/iam v1.5.3 // indirect
+	cloud.google.com/go/longrunning v0.7.0 // indirect
 	cloud.google.com/go/monitoring v1.24.2 // indirect
 	dario.cat/mergo v1.0.2 // indirect
 	github.com/Azure/go-ansiterm v0.0.0-20230124172434-306776ec8161 // indirect

go/go.sum

@@ -8,6 +8,8 @@ cloud.google.com/go/auth/oauth2adapt v0.2.8 h1:keo8NaayQZ6wimpNSmW5OPc283g65QNIi
 cloud.google.com/go/auth/oauth2adapt v0.2.8/go.mod h1:XQ9y31RkqZCcwJWNSx2Xvric3RrU88hAYYbjDWYDL+c=
 cloud.google.com/go/compute/metadata v0.9.0 h1:pDUj4QMoPejqq20dK0Pg2N4yG9zIkYGdBtwLoEkH9Zs=
 cloud.google.com/go/compute/metadata v0.9.0/go.mod h1:E0bWwX5wTnLPedCKqk3pJmVgCBSM6qQI1yTBdEb3C10=
+cloud.google.com/go/firestore v1.21.0 h1:BhopUsx7kh6NFx77ccRsHhrtkbJUmDAxNY3uapWdjcM=
+cloud.google.com/go/firestore v1.21.0/go.mod h1:1xH6HNcnkf/gGyR8udd6pFO4Z7GWJSwLKQMx/u6UrP4=
 cloud.google.com/go/iam v1.5.3 h1:+vMINPiDF2ognBJ97ABAYYwRgsaqxPbQDlMnbHMjolc=
 cloud.google.com/go/iam v1.5.3/go.mod h1:MR3v9oLkZCTlaqljW6Eb2d3HGDGK5/bDv93jhfISFvU=
 cloud.google.com/go/logging v1.13.0 h1:7j0HgAp0B94o1YRDqiqm26w4q1rDMH7XNRU34lJXHYc=

go/k8s/dev/particleprocessorworker.yaml

@@ -0,0 +1,31 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: particleprocessorworker
+spec:
+  selector:
+    matchLabels:
+      app: particleprocessorworker
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: particleprocessorworker
+    spec:
+      serviceAccountName: default-service-account
+      nodeSelector:
+        cloud.google.com/gke-spot: "true"
+      terminationGracePeriodSeconds: 15
+      containers:
+      - name: particleprocessorworker
+        image: "particleprocessorworker"
+        resources:
+          requests:
+            memory: "52Mi"
+            cpu: 50m
+          limits:
+            memory: "52Mi"
+            cpu: 50m
+        env:
+        - name: "GCP_PROJECT"
+          value: "flowy-dev-440017"

go/skaffold.yaml

@@ -34,6 +34,10 @@ profiles:
         context: .
         docker:
           dockerfile: Dockerfile
+      - image: particleprocessorworker
+        context: .
+        docker:
+          dockerfile: Dockerfile.particleprocessorworker
     manifests:
       rawYaml:
       - k8s/dev/*