使用Golang在Nginx后面运行的GRPC服务的TLS

Question

I have a flutter app (dart based) and a GoLang server, using GRPC.

I wanted to secure it, so I tried setting up Ngninx with certbot(I'm new at this), but the bot requires a challenge where it connects to the Web service (for the Domain) for an http response, which my service doesn't give. It is possible to run both GRPC and HTTP server on the same port, but I couldn't understand how to setup Nginx for that.

Then I tried setting up TLS for my service itself using autocert but doing that with acme requires the same web service response and without that I have to give manual certificates and skip insecure verify which isn't available in dart for now (only two options available secure and insecure). And testing autocert on local doesn't help either as it doesn't even create local certs (at least for me).

I also read about a DNS challenge which requires a DNS TXT record, but I'm not sure if it'll ask me to put up a new TXT record on every renewal.

Anyway, I'm mostly confused as to how to move forwards with this. I connect with GRPC to actual mobile apps and haven't found many tutorials or questions regarding this anywhere. My GoLang server also interacts with other internal micro-services, so making it TLS supported would also mean redeploying all other services with secure flag enabled.

Any help regarding what I should do to secure my GRPC connection to apps, would be amazing!

Relevant docs:

• https://www.nginx.com/blog/nginx-1-13-10-grpc/
• https://godoc.org/golang.org/x/crypto/acme/autocert
• https://serverfault.com/questions/750902/how-to-use-lets-encrypt-dns-challenge-validation
• https://d3void.net/post/acme/

Apologies if this is a stupid question, but I've been stuck on this for a week.

Answer 1

Just posting what I ended up doing for my setup. Nginx does support GRPC with version 1.3.10+ but requires a lot of manual work and a cron job to auto renew certificates, and it lacked documentation for a how-to.

I ended up using Traefik instead, I've documented the whole process and why I chose Traefik on a blog post here

In short, Traefik allowed for a simpler setup and very detailed GRPC documentation to get started. Another plus was it runs inside of a docker itself, so could easily test on my mac for the same version I'd deploy on the servers. It provided auto cert renewal in the box and with a DNS challenge, I could easily verify the domains.

Sample TOML file for TLS termination at the reverse proxy end, for GRPC and normal REST services, supporting http (for older apps) & https.

defaultEntryPoints = ["http", "https"]
logLevel = "INFO"
[traefikLog]
[accessLog]
  filePath = "/var/log/access.log"
  format = "json"
[entryPoints]
  [entryPoints.http]
  address = ":80"
  [entryPoints.https]
  address = ":443"
    [entryPoints.https.tls]
[api]
[file]
[acme]
email = "[e-mail]"
storage = "acme.json"
entryPoint = "https"
acmeLogging = true
  [acme.dnsChallenge]
    provider = "gcloud"
  [[acme.domains]]
    main = "*.example.com"
    sans = ["www.example.com"]
[backends]
  [backends.foo]
    [backends.foo.servers.server1]
    url = "h2c://127.0.0.1:3000"
  [backends.bar]
    [backends.bar.servers.server1]
    url = "http://127.0.0.1:3001"
[frontends]
  [frontends.foo]
  backend = "foo"
    [frontends.foo.routes.server1]
    rule = "Host:foo.example.com"
  passHostHeader = true
  passTLSCert = false
  [frontends.bar]
  backend = "bar"
    [frontends.bar.routes.server1]
    rule = "Host:bar.example.com"
  passHostHeader = true
  passTLSCert = false

Only issue was figuring out the Google Cloud settings for provider (dnsChallenge), which are quite hard to find and setup if doing for the first time! Read more about configuring traefik with GRPC here