Simple KV store testing HashMap in Zig

Author Mitja Felicijan <mitja.felicijan@gmail.com> 2024-09-18 07:57:02 +0200
Committer Mitja Felicijan <mitja.felicijan@gmail.com> 2024-09-18 07:57:02 +0200
Commit f07957d7e4a67792af5356ea3f8c09b318283cce (patch)
-rw-r--r-- README.md 4
-rw-r--r-- zig-kv-store/Makefile 2
-rw-r--r-- zig-kv-store/main.zig 94
3 files changed, 100 insertions, 0 deletions
diff --git a/README.md b/README.md
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> Check `shell.nix` to see the software and dependencies that are used
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> Check `shell.nix` to see the software and dependencies that are used
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> in these examples. If you use Nix just do `nix-shell shell.nix`.
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> in these examples. If you use Nix just do `nix-shell shell.nix`.
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Every test has it's own `Makefile` so please check that before you try
 
  
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running it.
 
  
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| Example                          | What does it do?                                               |
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| Example                          | What does it do?                                               |
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|----------------------------------|----------------------------------------------------------------|
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|----------------------------------|----------------------------------------------------------------|
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| [c-asm](./c-asm)                 | Calls a function written in ASM from C code.                   |
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| [c-asm](./c-asm)                 | Calls a function written in ASM from C code.                   |
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| [zig-x11](./zig-x11)             | Uses X11 to create a basic window without any bindings needed. |
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| [zig-x11](./zig-x11)             | Uses X11 to create a basic window without any bindings needed. |
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| [zig-http](./zig-http)           | Basic example of a HTTP 1.1 server without any routing etc.    |
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| [zig-http](./zig-http)           | Basic example of a HTTP 1.1 server without any routing etc.    |
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| [zig-x11-box](./zig-x11-box)     | Move a box around with arrow keys with Xlib and Zig.           |
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| [zig-x11-box](./zig-x11-box)     | Move a box around with arrow keys with Xlib and Zig.           |
 
  
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| [zig-kv-store](./zig-kv-store)   | Simple Key-value store that mimics memcached written in Zig.   |
diff --git a/zig-kv-store/Makefile b/zig-kv-store/Makefile 
  
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default:
 
  
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	zig run main.zig -freference-trace
diff --git a/zig-kv-store/main.zig b/zig-kv-store/main.zig 
  
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// https://github.com/memcached/memcached/wiki/Commands
 
  
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// https://ziglang.org/documentation/master/std/#std.hash_map.HashMap
 
  
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const std = @import("std");
 
  
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const Error = error{
 
  
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    Failed,
 
  
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    KeyNotFound,
 
  
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};
 
  
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const Store = struct {
 
  
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    data: std.StringHashMap([]const u8),
 
  
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    pub fn set(self: *Store, key: []const u8, value: []const u8) !void {
 
  
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        self.data.put(key, value) catch |err| {
 
  
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            std.log.err("Failed adding key `{s}` with error {}", .{ key, err });
 
  
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            return error.Failed;
 
  
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        };
 
  
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    }
 
  
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    pub fn get(self: *Store, key: []const u8) ![]const u8 {
 
  
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        if (self.data.get(key)) |value| {
 
  
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            return value;
 
  
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        }
 
  
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        return error.KeyNotFound;
 
  
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    }
 
  
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    pub fn del(self: *Store, key: []const u8) !void {
 
  
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        if (!self.data.remove(key)) {
 
  
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            std.log.err("Failed deleting key `{s}`", .{key});
 
  
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            return error.KeyNotFound;
 
  
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        }
 
  
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    }
 
  
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};
 
  
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pub fn main() !void {
 
  
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    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
 
  
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    defer arena.deinit();
 
  
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    var allocator = arena.allocator();
 
  
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    var store = Store{ .data = std.StringHashMap([]const u8).init(allocator) };
 
  
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    defer store.data.deinit();
 
  
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    // Setting new key.
 
  
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    {
 
  
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        const key = "johhny";
 
  
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        try store.set(key, "blaze");
 
  
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    }
 
  
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    // Retrieving back existing key if we know it will never return an error.
 
  
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    {
 
  
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        const key = "johhny";
 
  
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        const result = store.get(key) catch unreachable;
 
  
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        std.log.info("Value: {s}", .{result});
 
  
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    }
 
  
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    // Retrieving back the value and handling errors.
 
  
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    {
 
  
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        const key = "unknown";
 
  
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        if (store.get(key)) |val| {
 
  
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            std.log.info("Value: {s}", .{val});
 
  
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        } else |err| {
 
  
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            std.log.err("Error: {any}", .{err});
 
  
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        }
 
  
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    }
 
  
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    // Retrieving back key that does not exist and handling specific errors.
 
  
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    {
 
  
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        const key = "unknown";
 
  
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        if (store.get(key)) |val| {
 
  
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            std.log.info("Value: {s}", .{val});
 
  
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        } else |err| switch (err) {
 
  
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            error.KeyNotFound => {
 
  
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                std.log.err("Key `{s}` was not found", .{key});
 
  
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            },
 
  
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        }
 
  
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    }
 
  
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    // Deleting existing key.
 
  
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    {
 
  
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        const key = "johhny";
 
  
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        try store.del(key);
 
  
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    }
 
  
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    // Retrieving back the value and handling errors.
 
  
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    {
 
  
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        const key = "johnny";
 
  
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        if (store.get(key)) |val| {
 
  
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            std.log.info("Value: {s}", .{val});
 
  
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        } else |err| {
 
  
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            std.log.err("Error: {any}", .{err});
 
  
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        }
 
  
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    }
 
  
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}