Implementation of Ping Discovery Service (#73)

This includes * Go code to lookup Ping Services, and return one for each region (randomly distributed across requests). * README for API description and basic building and running steps. * Docker file for image building. Next will be creating a Cloud Build and Cloud Deploy to take it live (and hopefully set the template for that work). Work on #46
googleforgames · Feb 24, 2023 · 839f6a3 · 839f6a3
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diff --git a/services/ping-discovery/Dockerfile b/services/ping-discovery/Dockerfile
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+#
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+FROM golang:1.19 as build
+
+WORKDIR /go/src/ping-discovery
+COPY . .
+
+RUN go mod download
+RUN go vet -v
+RUN go test -v
+
+RUN CGO_ENABLED=0 go build -o /go/bin/ping-discovery
+
+FROM gcr.io/distroless/static-debian11:nonroot
+
+COPY --from=build /go/bin/ping-discovery /
+
+ENV GIN_MODE=release
+USER nonroot:nonroot
+CMD ["/ping-discovery"]
diff --git a/services/ping-discovery/README.md b/services/ping-discovery/README.md
@@ -0,0 +1,75 @@
+# Ping Discovery Service
+
+This service will inspect a Google Cloud project for 
+[Agones Latency Ping endpoints](https://agones.dev/site/docs/guides/ping-service/), and return one for each region 
+that Agones is installed.
+
+The Service will choose an endpoint at random on each request for each region, assuming there are more than one. 
+This is to distribute the load amongst clusters.
+
+## API
+
+<table>
+    <thead>
+        <td>Endpoint</td>
+        <td>Input</td>
+        <td>Return</td>
+        <td>Description</td>
+    </thead>
+    <tbody>
+        <tr>
+            <td><code>GET /list</code></td>
+            <td> None </td>
+            <td>
+                <pre>
+{
+    "asia-east1": {
+        "Name": "agones-ping-udp-service",
+        "Namespace": "agones-system",
+        "Region": "asia-east1",
+        "Address": "104.155.211.151",
+        "Protocol": "UDP"
+    },
+    "europe-west1": {
+        "Name": "agones-ping-udp-service",
+        "Namespace": "agones-system",
+        "Region": "europe-west1",
+        "Address": "34.22.151.131",
+        "Protocol": "UDP"
+    },
+    "us-central1": {
+        "Name": "agones-ping-udp-service",
+        "Namespace": "agones-system",
+        "Region": "us-central1",
+        "Address": "35.227.137.95",
+        "Protocol": "UDP"
+    }
+}
+                </pre>
+            </td>
+            <td>
+                Map of region, where the key is the region name, and a singular
+                endpoint for the UDP ping service for each region as the value.
+            </td>
+        </tr>
+    </tbody>
+</table>
+
+## Running locally
+
+When running locally, make sure you have [gcloud](https://cloud.google.com/sdk/docs/install) installed,
+and a default project authenticated and configured, so that the binary can determine the project it should be 
+scanning for
+Ping endpoints.
+
+```shell
+go run main.go
+```
+
+## Building image
+
+```shell
+docker build . -t ping-discovery
+```
+
+Note: The docker image will fail locally, since it has no access Google Cloud Application Default Credentials.
diff --git a/services/ping-discovery/go.mod b/services/ping-discovery/go.mod
@@ -0,0 +1,47 @@
+module ping-discovery
+
+go 1.19
+
+require (
+	cloud.google.com/go/compute v1.18.0
+	github.com/gin-gonic/gin v1.9.0
+	github.com/jellydator/ttlcache/v3 v3.0.1
+	golang.org/x/oauth2 v0.5.0
+	google.golang.org/api v0.108.0
+)
+
+require (
+	cloud.google.com/go/compute/metadata v0.2.3 // indirect
+	github.com/bytedance/sonic v1.8.0 // indirect
+	github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311 // indirect
+	github.com/gin-contrib/sse v0.1.0 // indirect
+	github.com/go-playground/locales v0.14.1 // indirect
+	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-playground/validator/v10 v10.11.2 // indirect
+	github.com/goccy/go-json v0.10.0 // indirect
+	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.2.1 // indirect
+	github.com/googleapis/gax-go/v2 v2.7.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
+	github.com/leodido/go-urn v1.2.1 // indirect
+	github.com/mattn/go-isatty v0.0.17 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pelletier/go-toml/v2 v2.0.6 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	github.com/ugorji/go/codec v1.2.9 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	golang.org/x/arch v0.0.0-20210923205945-b76863e36670 // indirect
+	golang.org/x/crypto v0.5.0 // indirect
+	golang.org/x/net v0.7.0 // indirect
+	golang.org/x/sync v0.1.0 // indirect
+	golang.org/x/sys v0.5.0 // indirect
+	golang.org/x/text v0.7.0 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/genproto v0.0.0-20230124163310-31e0e69b6fc2 // indirect
+	google.golang.org/grpc v1.51.0 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)