!doc.md

File Dropper Service

This service is intended to be ran across a fleet of servers (bare metal or virtualized) to keep configuration files up to date. The clients connect to a centralized server who's implementation is out of scope for this assignment.

Your client should initiate a server-side streaming Watch request that will emit events on source updates. It's up to the client to consume this event stream and keep the requested files up to date. After connecting and making the watch request, OpSync will be the first message received. Additionally, the OpSync event may be received at any point in the stream for various upstream reasons. OpUpdate and OpRemove are called when files must be updated or removed from the destination system.

Resources:

• https://grpc.io/docs/languages/

dropper.proto

syntax = "proto3";

package dropperv1;

/// A struct describing a file item to be updated on the target.
message FileItem {
    /// File destination path
    string path = 1;
    /// File contents (bytes)
    bytes contents = 2;
    /// File Permissions
    uint32 permissions = 3;
    /// File owner (user id)
    string user = 4;
    /// File group (group id)
    string group = 5;
    /// Shell command to run on file change
    string command = 6;
}

/// A watch request, parameters are derived from client identity.
message WatchRequest {}

/// A message sent from the watch stream.
message WatchResponse {
    /// Sent when the client has reconnected or fallen behind.
    /// Contains the whole list of files.
    message OpSync {
        repeated FileItem items = 1;
    }

    /// Sent when a single file entry has been updated.
    message OpUpdate {
        FileItem item = 1;
    }

    /// Sent when a single file entry has been removed.
    message OpRemove {
        string path = 1;
    }

    /// The possible message types sent during a watch session.
    oneof op {
        OpSync sync = 1;
        OpUpdate update = 2;
        OpRemove remove = 3;
    }
}

/// Dropper service provides an op stream.
service DropperService {
    rpc Watch(WatchRequest) returns (stream WatchResponse);
}