Startup failure when proto package doesn't contain service

Describe the bug The following error is reported by the server upon startup when the proto file below is included in grpc/protos:

/usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js:140
                    let methods = Object.keys(service);
                                         ^

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at /usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js:140:42
    at Array.forEach (<anonymous>)
    at Protocols.initGrpc (/usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js:122:22)
    at Object.start (/usr/local/lib/node_modules/camouflage-server/dist/index.js:171:19)
    at Object.<anonymous> (/usr/local/lib/node_modules/camouflage-server/bin/camouflage.js:280:14)
    at Module._compile (node:internal/modules/cjs/loader:1095:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1124:10

To Reproduce Steps to reproduce the behavior:

Add the following file to grpc/protos:
```
syntax = "proto3";
```

package com.livongo.protobuf.grpc.internal_non_production.template;

import "google/protobuf/wrappers.proto"; import "google/api/annotations.proto";

/**

HelloWorld++ service. Has unary and streaming APIs. */ service HelloWorld { / Pass in your name and get back a clever, personalized greeting! */ rpc SayHello (ToBeGreeted) returns (Greeting) { option (google.api.http) = { post: "/v1/sayhello" }; } /* Pass in a message and have it echoed back with embellishments! / rpc SayAnything (Greeting) returns (Greeting) { option (google.api.http) = { post: "/v1/sayanything" }; } /
- Optionally pass in a number N (defaults to 1), and it returns a stream of N random numbers. */ rpc GenIntStream (google.protobuf.Int32Value) returns (stream google.protobuf.Int32Value) { option (google.api.http) = { post: "/v1/genIntStream" }; }
// Pass in a stream of numbers (e.g., output from GenIntStream), and it returns a stream of min/max messages, // with an updated message emitted whenever the min and/or max seen so far in the input changes. rpc IntStreamToStatsStream (stream google.protobuf.Int32Value) returns (stream MinMax) { option (google.api.http) = { post: "/v1/intStreamToStatsStream" }; } }

// This is doc for message message ToBeGreeted { message Person { string name = 1; }

// A greetee is a person
Person person = 1;
google.protobuf.StringValue msg = 2;

}

message Greeting { string message = 1; }

message Nothing { }

message MinMax { int32 min = 1; int32 max = 2; }


**Expected behavior**
No error upon startup should happen due to the above proto file.

**Desktop (please complete the following information):**
- OS: MacOS Catalina
- camouflage-server 0.5.1

**Additional context**
The following patch to add a guard around the possibly undefined `service` variable fixes the problem:

137a138

            if (typeof service !== 'undefined') {

159c160,161 < });

            }});

Here's the log output when the error happens:

2021-07-26 13:27:07 debug: Camouflage configuration:
========
mocks_dir | ws.mocks_dir | http.port | http.enable | https.enable | http2.enable | grpc.enable | ws.enable | cache.enable | injection.enable | origins | ssl.key | ssl.cert | https.port | http2.port | grpc.host | grpc.port | grpc.mocks_dir | grpc.protos_dir | loglevel | backup.enable | backup.cron | configFile | ext_helpers | cache.ttl_seconds
========
./mocks | ./ws_mocks | 8080 | false | false | false | true | false | false | false | http://localhost:3000/,http://localhost:3001/,http://localhost:5000/ | ./certs/server.key | ./certs/server.cert | 8443 | 8081 | 8082 | localhost | 4312 | ./grpc/mocks | ./grpc/protos | debug | false | 0 * * * * | config.yml | ./custom_handlebar.json | 300
========

2021-07-26 13:27:07 info: [41045] Master Started 
2021-07-26 13:27:07 info: Cluster metrics server listening to 5555, metrics exposed on http://localhost:5555/metrics 
(node:41045) [DEP0111] DeprecationWarning: Access to process.binding('http_parser') is deprecated.
(Use `node --trace-deprecation ...` to show where the warning was created)
2021-07-26 13:27:08 info: CORS enabled for http://localhost:3000/, http://localhost:3001/, http://localhost:5000/ 
2021-07-26 13:27:08 info: [41048] Worker started 
2021-07-26 13:27:08 info: Handlebar helpers registration started 
2021-07-26 13:27:08 warn: Code Injection is disabled. Handlebars such as code and inject and functionalities such as external helpers, will not work.  
2021-07-26 13:27:08 info: Handlebar helpers registration completed 
2021-07-26 13:27:08 debug: Registering Unary method: createBlog 
2021-07-26 13:27:08 debug: Registering Unary method: listBlogs 
2021-07-26 13:27:08 debug: Registering Unary method: SayHello 
2021-07-26 13:27:08 debug: Registering Unary method: SayAnything 
2021-07-26 13:27:08 debug: Registering method with server side streaming: GenIntStream 
2021-07-26 13:27:08 debug: Registering method with BIDI streaming: IntStreamToStatsStream 
/usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js.orig:138
                let methods = Object.keys(service);
                                     ^

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at /usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js.orig:138:38
    at Array.forEach (<anonymous>)
    at Protocols.initGrpc (/usr/local/lib/node_modules/camouflage-server/dist/protocols/index.js.orig:122:22)
    at Object.start (/usr/local/lib/node_modules/camouflage-server/dist/index.js:171:19)
    at Object.<anonymous> (/usr/local/lib/node_modules/camouflage-server/bin/camouflage.js:280:14)
    at Module._compile (node:internal/modules/cjs/loader:1095:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1124:10)
    at Module.load (node:internal/modules/cjs/loader:975:32)
    at Function.Module._load (node:internal/modules/cjs/loader:816:12)
2021-07-26 13:27:08 warn: [41048] Worker Stopped Mon Jul 26 2021 13:27:08 GMT-0700 (Pacific Daylight Time)

testinggospels / camouflage

Startup failure when proto package doesn't contain service #73

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