GRPC sample service

Server

This is ticket review score calculator that masquerades as GRPC sample service :) Weights are used to amplify ratings by category:

weighted rating = (rating * weight) + rating

0-100 score gets calculated:

score = ((rating * weight) + rating)/((maxRating * weight) + maxRating) * 100

Reguired for building the project locally:

• go
• Protocol Buffer Compiler protoc

Run service locally:

# Download dependencis
go mod download
# Generate protobuf file
./protoc-code.sh
# Optionally also vendor dependencies
go mod vendor -mod=readonly
# run the service
go run cmd/server/main.go

Supported service flags:

  -db-file="database.db": Path to SQLite file path
  -db-host="localhost": PostgreSQL address
  -db-name="": PostgreSQL database name
  -db-password="": PostgreSQL password
  -db-port=5432: PostgreSQL port
  -db-user="": PostgreSQL user
  -docs-path="./pb": Documentation html and proto definition directory
  -grpc-port=8080: Service port to listen for GRPC requests
  -http-port=8081: Service port to listen for HTTP requests

All the flags can also be passed in as environment variables.

If -db-user, -db-password and db-name it will try to connect to PostgreSQL. Otherwise it will attempt to open SQLite database file. By default it uses the SQLite database found in the repository. There is also migrate-to-psql.sh to migrate data to a local PostgreSQL database.

Health check works with grpc-health-probe:

./grpc_health_probe -addr=:8080

In addition to GRPC methods the following HTTP methods are served:

• /metrics Prometheus metrics endpoint
• /docs Proto service documentation page
• /proto Service proto file

Also available in Docker Hub:

docker pull tanelmae/grpc-sample

---

CLI client

Simple CLI client is found in cmd/client/main.go.

Supported subcommands and flags:

category-scores
  -from string
    	Start time for the period (default "2019-03-01")
  -to string
    	End time for the period (default "2019-04-01")

ticket-scores
  -from string
    	Start time for the period (default "2019-03-01")
  -to string
    	End time for the period (default "2019-04-01")

overal-score
  -from string
    	Start time for the period (default "2019-03-01")
  -out string
    	Format for the command output (default "silent")

period-diff
  -from string
    	Start time for the period (default "2019-03-01")
  -to string
    	End time for the period (default "2019-04-01")
  -second-from string
    	Start time for the period (default "2019-04-01")
  -second-to string
    	End time for the period (default "2019-04-30")

Shared flags for all commands
  -out string
    	Format for the command output (default "json")
      Also available: "table" and "silent"
  -addr string: Server address (default "localhost:8080")

Example:

batman@gotham:grpc-sample $ go run cmd/client/main.go period-diff -out table
+------------+--------+
|  CATEGORY  | CHANGE |
+------------+--------+
| Spelling   | 2 %    |
| Grammar    | 2 %    |
| GDPR       | -1 %   |
| Randomness | 0 %    |
+------------+--------+