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initial readme for grpc project (#51)
* initial readme for grpc project * Update README.md * Update README.md * Initial version of grpc project * Initial version of grpc project * Initial version of grpc project * Update README.md * Update README.md * Updated: added skeleton code and proto * comments * fix * few more points * fixes * fix * Update grpc-client-server/prober_client/main.go Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update grpc-client-server/README.md Co-authored-by: Daniel Wagner-Hall <[email protected]> * Update README.md * Update grpc-client-server/prober_client/main.go Co-authored-by: Daniel Wagner-Hall <[email protected]> Co-authored-by: Daniel Wagner-Hall <[email protected]>
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| .DS_Store | ||
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| # GRPC Client and Server Communication | ||
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| Timebox: 3 days | ||
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| Learning objectives: | ||
| * Learn what gRPC is and how it differs from HTTP | ||
| * Understand what kinds of issues can occur in a real system and how to defend against them | ||
| * Learn what observability is, and what are some kinds of observability you'd find in use in production? | ||
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| ## What is gRPC? | ||
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| We've used simple HTTP request so far, making and handling GET and POST requests. | ||
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| RPC is another way to communicate between clients and servers (or frontends and backends). | ||
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| It is used commonly within an organisation (it isn't used from browsers), where it has advantages around types, performance, and streaming. | ||
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| gRPC is not used to communicate from web browsers to servers (important because this is context they have). | ||
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| RPCs let you call a specific function on another computer. RPCs are highly structured; normally the request and response are encoded in efficient binary formats which are not human-readable. HTTP APIs are usually limited to CRUD (Create, Read, Update, Delete) operations and RPCs can perform any kind of operation. | ||
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| If you want to efficiently integrate two systems that you control, RPCs are a good choice. If you want to provide an API for use by developers outside of your organisation then HTTP APIs are generally a better choice, because they are simpler to develop against, all programming languages provide good HTTP support, and HTTP works in the browser. | ||
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| gRPC, which we will use in this exercise, is a RPC implementation that is fairly common in industry. | ||
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| Read the [gRPC Introduction](https://grpc.io/docs/what-is-grpc/introduction/) and | ||
| [gRPC Core Concepts](https://grpc.io/docs/what-is-grpc/core-concepts/) for an overview of gRPC. | ||
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| ## Run the gRPC Quick Start Hello World Example | ||
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| Run through the [gRPC Hello World example](https://grpc.io/docs/languages/go/quickstart/) from the grpc.io documentation. | ||
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| This will ensure you have the right tools on your machine and working correctly. | ||
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| ## Build a gRPC based prober | ||
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| Next, we will implement a simple prober service. Imagine that we want to verify that our site is available and has acceptable latency from many different locations around the world. We build a program that performs HTTP GETs on a provided endpoint and returns statistics about how long it took. | ||
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| In a real production system, we could run several instances of our prober server in different regions and use one client to query all of the prober servers. | ||
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| In the same directory as this README you will find initial versions of: | ||
| * the protocol buffer definition | ||
| * prober server Go code | ||
| * prober client Go code | ||
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| Generate the generated protobuf code: | ||
| ```console | ||
| > protoc --go_out=. --go_opt=paths=source_relative \ | ||
| --go-grpc_out=. --go-grpc_opt=paths=source_relative \ | ||
| prober/prober.proto | ||
| ``` | ||
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| Observe the new generated files: | ||
| ```console | ||
| > ls prober | ||
| > prober.pb.go prober.proto prober_grpc.pb.go | ||
| ``` | ||
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| Read through `prober_grpc.pb.go` - this is the interface we will use in our code. This is how gRPC works: a `proto` format | ||
| gets generated into language-specific code that we can use to interact with gRPCs. If we're working with multiple programming languages | ||
| that need to interact through RPCs, we can do this by generating from the same protocol buffer definition with the language-specific | ||
| tooling. | ||
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| Now run the server and client code. You should see output like this. | ||
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| ```console | ||
| > go run prober_server/main.go | ||
| > 2022/10/19 17:51:32 server listening at [::]:50051 | ||
| ```` | ||
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| ```console | ||
| > go run prober_client/main.go | ||
| > 2022/10/19 17:52:15 Response Time: 117.000000 | ||
| ``` | ||
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| We've now gained some experience with the protocol buffer format, learned | ||
| how to generate Go code from protocol buffer definitions, and called that code from Go programs. | ||
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| ## Implement prober logic | ||
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| Let's modify the prober service slightly. Instead of the simple one-off HTTP GET against a hardcoded google.com, we are going to modify the service to probe an HTTP endpoint N times and return the average time to GET that endpoint to the client. | ||
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| Change your prober request and response: | ||
| * Add a field to the `ProbeRequest` for the number of requests to make. | ||
| * Rename the field in `ProbeReply` (and perhaps add a comment) to make clear it's the _average_ response time of the several requests. | ||
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| Note that it's ok to rename fields in protobuf (unlike when we use JSON), because the binary encoding of protobuf messages doesn't include field names. You can [read more about backward/forward compatibility with protobufs](https://earthly.dev/blog/backward-and-forward-compatibility/) if you want. | ||
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| Remember that you'll need to re-generate your Go code after changing your proto definitions. | ||
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| Update your client to read the endpoint and number of repetitions from the [command line](https://gobyexample.com/command-line-arguments). | ||
| Then update your server to execute the probe: do a HTTP fetch of `endpoint` the specified number of times. | ||
| The initial version of the code demonstrates how to use the standard [`net/http` package](https://pkg.go.dev/net/http) and the standard time package. | ||
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| Add up all the elapsed times, divide by the number of repetitions, and return the average to the client. | ||
| The client should print out the average value received. | ||
| You can do arithmetic operations like addition and division on `time.Duration` values in Go. | ||
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| ## Add a client timeout | ||
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| Maybe the site we are probing is very slow (which can happen for all kinds of reasons, from network problems to excessive load), | ||
| or perhaps the number of repetitions is very high. | ||
| Either way, we never want our program to wait forever. | ||
| If we are not careful about preventing this then we can end up building systems where problems in one small part of the system | ||
| spread across all of the services that talk to that part of the system. | ||
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| On the client side, add a [timeout](https://pkg.go.dev/context#WithTimeout) to stop waiting after 1 second. | ||
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| Run your client against some website - how many repetitions do you need to see your client timeout? | ||
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| ## Handling Errors | ||
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| How do we know if the HTTP fetch succeeded at the server? Add a check to make sure it did. | ||
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| How should we deal with errors, e.g. if the endpoint isn't found, or says the server is in an error state? | ||
| Modify your code and proto format to handle these cases. | ||
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| ## Extra Challenge: Serve and Collect Prometheus Metrics | ||
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| These sections are optional - do them for an extra challenge if time permits. | ||
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| ### Part 1: Add Prometheus Metrics | ||
| Let's learn something about how to monitor applications. | ||
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| In software operations, we want to know what our software is doing and how it is performing. | ||
| One very useful technique is to have our program export metrics. Metrics are basically values that your | ||
| program makes available (the industry standard is to export and scrape over HTTP). | ||
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| Specialised programs, such as Prometheus, can then fetch metrics regularly | ||
| from all the running instances of your program, store the history of these metrics, and do useful arithmetic on them | ||
| (like computing rates, averages, and maximums). We can use this data to do troubleshooting and to alert if things | ||
| go wrong. | ||
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| Read the [Overview of Prometheus](https://prometheus.io/docs/introduction/overview/). | ||
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| Now add Prometheus metrics to your prober server. Every time you execute a probe, update a `gauge` metric that tracks the latency. | ||
| Add a `label` specifying the endpoint being probed. | ||
| The [Prometheus Guide to Instrumenting a Go Application](https://prometheus.io/docs/guides/go-application/) has all the information you need to do this. | ||
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| Once you've run your program, use your client to execute probes against some endpoint. | ||
| Now use the `curl` program or your browser to view the metrics. | ||
| You should see a number of built-in Go metrics, plus your new gauge. | ||
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| If you use your client to start probing a second endpoint, you should see a second labelled metric appear. | ||
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| ### Part 2: Scrape Prometheus Metrics | ||
| The final step is to set up the Prometheus application to periodically pull metrics from your `prober_server`. | ||
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| The easiest way to run Prometheus locally is in Docker. This way we can run an up-to-date version that has been built by the Prometheus maintainers. | ||
| See [Prometheus Installation](https://prometheus.io/docs/prometheus/latest/installation/). | ||
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| You'll need to set up a simple configuration to scrape your `prober_server`. Prometheus [configuration](https://prometheus.io/docs/prometheus/latest/configuration/configuration/) is quite complex but you can adapt this [example configuration](https://github.com/prometheus/prometheus/blob/main/documentation/examples/prometheus.yml). | ||
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| Next, find your custom gauge metric from your `prober_server` in http://localhost:9090/metrics. | ||
| Graph it in http://localhost:9090/graph. |
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| module github.com/CodeYourFuture/immersive-go-course/grpc-client-server | ||
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| go 1.19 | ||
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| require ( | ||
| github.com/golang/protobuf v1.5.2 // indirect | ||
| golang.org/x/net v0.0.0-20201021035429-f5854403a974 // indirect | ||
| golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4 // indirect | ||
| golang.org/x/text v0.3.3 // indirect | ||
| google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 // indirect | ||
| google.golang.org/grpc v1.50.1 // indirect | ||
| google.golang.org/protobuf v1.27.1 // indirect | ||
| ) |
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| cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw= | ||
| github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU= | ||
| github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU= | ||
| github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw= | ||
| github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4= | ||
| github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c= | ||
| github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q= | ||
| github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A= | ||
| github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U= | ||
| github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U= | ||
| github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8= | ||
| github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:xKAWHe0F5eneWXFV3EuXVDTCmh+JuBKY0li0aMyXATA= | ||
| github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs= | ||
| github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w= | ||
| github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0= | ||
| github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8= | ||
| github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk= | ||
| github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw= | ||
| github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY= | ||
| github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M= | ||
| github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU= | ||
| github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU= | ||
| github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE= | ||
| github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE= | ||
| github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA= | ||
| golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= | ||
| golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto= | ||
| golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA= | ||
| golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE= | ||
| golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU= | ||
| golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc= | ||
| golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4= | ||
| golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4= | ||
| golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4= | ||
| golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= | ||
| golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= | ||
| golang.org/x/net v0.0.0-20201021035429-f5854403a974 h1:IX6qOQeG5uLjB/hjjwjedwfjND0hgjPMMyO1RoIXQNI= | ||
| golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU= | ||
| golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U= | ||
| golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= | ||
| golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= | ||
| golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= | ||
| golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= | ||
| golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= | ||
| golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= | ||
| golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= | ||
| golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4 h1:myAQVi0cGEoqQVR5POX+8RR2mrocKqNN1hmeMqhX27k= | ||
| golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= | ||
| golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= | ||
| golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k= | ||
| golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ= | ||
| golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ= | ||
| golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ= | ||
| golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY= | ||
| golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs= | ||
| golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q= | ||
| golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= | ||
| google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM= | ||
| google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4= | ||
| google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc= | ||
| google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc= | ||
| google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 h1:+kGHl1aib/qcwaRi1CbqBZ1rk19r85MNUf8HaBghugY= | ||
| google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo= | ||
| google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c= | ||
| google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg= | ||
| google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk= | ||
| google.golang.org/grpc v1.50.1 h1:DS/BukOZWp8s6p4Dt/tOaJaTQyPyOoCcrjroHuCeLzY= | ||
| google.golang.org/grpc v1.50.1/go.mod h1:ZgQEeidpAuNRZ8iRrlBKXZQP1ghovWIVhdJRyCDK+GI= | ||
| google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8= | ||
| google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0= | ||
| google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM= | ||
| google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE= | ||
| google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo= | ||
| google.golang.org/protobuf v1.22.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU= | ||
| google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU= | ||
| google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw= | ||
| google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc= | ||
| google.golang.org/protobuf v1.27.1 h1:SnqbnDw1V7RiZcXPx5MEeqPv2s79L9i7BJUlG/+RurQ= | ||
| google.golang.org/protobuf v1.27.1/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc= | ||
| honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4= | ||
| honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4= |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,21 @@ | ||
| syntax = "proto3"; | ||
|
|
||
| option go_package = "github.com/CodeYourFuture/immersive-go-course/grpc-client-server/prober"; | ||
|
|
||
| package prober; | ||
|
|
||
| // The prober service definition. | ||
| service Prober { | ||
| rpc DoProbes (ProbeRequest) returns (ProbeReply) {} | ||
| } | ||
|
|
||
| // The request message | ||
| message ProbeRequest { | ||
| string endpoint = 1; | ||
| } | ||
|
|
||
| // The response message containing the result | ||
| message ProbeReply { | ||
| float result = 1; | ||
| } | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,38 @@ | ||
| // Package main implements a client for Prober service. | ||
| package main | ||
|
|
||
| import ( | ||
| "context" | ||
| "flag" | ||
| "log" | ||
|
|
||
| pb "github.com/CodeYourFuture/immersive-go-course/grpc-client-server/prober" | ||
| "google.golang.org/grpc" | ||
| "google.golang.org/grpc/credentials/insecure" | ||
| ) | ||
|
|
||
| var ( | ||
| addr = flag.String("addr", "localhost:50051", "the address to connect to") | ||
| ) | ||
|
|
||
| func main() { | ||
| flag.Parse() | ||
| // Set up a connection to the server. | ||
| conn, err := grpc.Dial(*addr, grpc.WithTransportCredentials(insecure.NewCredentials())) | ||
| if err != nil { | ||
| log.Fatalf("did not connect: %v", err) | ||
| } | ||
| defer conn.Close() | ||
| c := pb.NewProberClient(conn) | ||
|
|
||
| // Contact the server and print out its response. | ||
| ctx := context.Background() // TODO: add a timeout | ||
|
|
||
| // TODO: endpoint should be a flag | ||
| // TODO: add number of times to probe | ||
| r, err := c.DoProbes(ctx, &pb.ProbeRequest{Endpoint: "http://www.google.com"}) | ||
| if err != nil { | ||
| log.Fatalf("could not probe: %v", err) | ||
| } | ||
| log.Printf("Response Time: %f", r.GetResult()) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,47 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "context" | ||
| "flag" | ||
| "fmt" | ||
| "log" | ||
| "net" | ||
| "net/http" | ||
| "time" | ||
|
|
||
| pb "github.com/CodeYourFuture/immersive-go-course/grpc-client-server/prober" | ||
| "google.golang.org/grpc" | ||
| ) | ||
|
|
||
| var ( | ||
| port = flag.Int("port", 50051, "The server port") | ||
| ) | ||
|
|
||
| // server is used to implement prober.ProberServer. | ||
| type server struct { | ||
| pb.UnimplementedProberServer | ||
| } | ||
|
|
||
| func (s *server) DoProbes(ctx context.Context, in *pb.ProbeRequest) (*pb.ProbeReply, error) { | ||
| // TODO: support a number of repetitions and return average latency | ||
| start := time.Now() | ||
| _, _ = http.Get(in.GetEndpoint()) // TODO: add error handling here and check the response code | ||
| elapsed := time.Since(start) | ||
| elapsedMsecs := float32(elapsed / time.Millisecond) | ||
|
|
||
| return &pb.ProbeReply{Result: elapsedMsecs}, nil | ||
| } | ||
|
|
||
| func main() { | ||
| flag.Parse() | ||
| lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port)) | ||
| if err != nil { | ||
| log.Fatalf("failed to listen: %v", err) | ||
| } | ||
| s := grpc.NewServer() | ||
| pb.RegisterProberServer(s, &server{}) | ||
| log.Printf("server listening at %v", lis.Addr()) | ||
| if err := s.Serve(lis); err != nil { | ||
| log.Fatalf("failed to serve: %v", err) | ||
| } | ||
| } |