echolot grpc

echolot grpc describes gRPC services and calls their methods, with messages written as JSON. It learns the services from the server's reflection, or from a .proto file. See gRPC requests for the same in the app.

Subcommand	What it does
`echolot grpc describe`	Lists the services and methods of a server or a `.proto` file, with each method's fields.
`echolot grpc call`	Calls a method and prints the answer as JSON.

The examples use the Alpenglow inventory service, specs/inventory.proto in the Alpenglow workspace. It runs on your Mac at localhost:50051; the demo API can't serve gRPC.

echolot grpc describe

echolot grpc describe [<url>] [--proto <file>] [--header <header> ...] [--insecure] [--timeout <seconds>] [--json]

echolot grpc describe --proto Alpenglow.echolot/specs/inventory.proto

Alpenglow.echolot/specs/inventory.proto: 1 service
alpenglow.inventory.v1.Inventory
  ListWarehouses (unary): alpenglow.inventory.v1.ListWarehousesRequest → alpenglow.inventory.v1.ListWarehousesResponse
  WatchStock (server streaming): alpenglow.inventory.v1.WatchStockRequest → alpenglow.inventory.v1.StockLevel
    skus: repeated string
  Reserve (unary): alpenglow.inventory.v1.ReserveRequest → alpenglow.inventory.v1.Reservation
    sku: string
    quantity: int32
    orderId: string

Give a server instead (echolot grpc describe http://localhost:50051) to ask its reflection service. Each method shows whether it is unary, server streaming, client streaming or bidirectional, its request and response types, and the fields of its request.

Option	Meaning
`<url>`	The server, `http://host:port` or `https://host:port`. Not needed with `--proto`.
`--proto <file>`	A `.proto` file describing the service, with its imports beside it. Without it, the server's reflection is asked.
`-H`, `--header <header>`	Metadata as `'Name: value'`. Repeatable.
`-k`, `--insecure`	Skip TLS certificate verification.
`--timeout <seconds>`	Seconds to wait for the whole call. Default 30.
`--json`	Print the description as JSON.

echolot grpc call

echolot grpc call <url> <method> [--data <json>] [--deadline <ms>] [--compress <algorithm>] [--proto <file>] [--header <header> ...] [--insecure] [--timeout <seconds>]

<method> is package.Service/Method. The message is JSON, {} by default; -d - reads it from standard input. For a client-streaming method, give an array: each element is one message. The answer prints as JSON on standard output.

echolot grpc call http://localhost:50051 alpenglow.inventory.v1.Inventory/Reserve \
  -d '{"sku": "TNT-MH-2P", "quantity": 1, "orderId": "ord_7Hk2Lw"}' \
  --proto Alpenglow.echolot/specs/inventory.proto

The status, the number of messages received and the time go to standard error. A status other than OK exits with 1.

Option	Meaning
`-d`, `--data <json>`	The message as JSON; `-` reads it from standard input. Default `{}`.
`--deadline <ms>`	The deadline in milliseconds, sent as `grpc-timeout`.
`--compress <algorithm>`	Compress the messages sent: `gzip` or `deflate`. Compressed answers are read either way.
`--proto <file>`	A `.proto` file describing the service, with its imports beside it. Without it, the server's reflection is asked.
`-H`, `--header <header>`	Metadata as `'Name: value'`. Repeatable.
`-k`, `--insecure`	Skip TLS certificate verification.
`--timeout <seconds>`	Seconds to wait for the whole call. Default 30.

http:// speaks HTTP/2 without TLS; https:// uses TLS. The well-known types (google.protobuf.Timestamp and the others) are built in, so a .proto file that imports them needs nothing beside it.

Exit codes

Code	When
`0`	`describe` found the services; `call` ended with status `OK`.
`1`	The server couldn't be reached or described, or the call's status wasn't `OK`.
`64`	A wrong option.

echolot grpc

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echolot grpc describe

echolot grpc call

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