v0.0.14 - lazy dependencies

README.md

@@ -7,7 +7,23 @@ Command line app to query an NTP server, to verify your OS clock setting.
 - [on Codeberg](https://codeberg.org/FObersteiner/ntp_client)
 - [on github](https://github.com/FObersteiner/ntp-client)
 
-```text
+## Usage
+
+### Building the binary
+
+```sh
+zig build -Dexe [--release=[safe|small|fast]]
+# build and run, debug: zig build -Dexe run
+# library tests: zig build test
+```
+
+### NTP library
+
+NTP library (`src/ntp.zig`) can be used independently in other projects; it is exposed via this project's `build.zig` and `build.zig.zon` files. Other dependencies of the binary are lazy, i.e. they won't be fetched if you use only the library in another project.
+
+### Usage of the binary
+
+```sh
 Usage: ntp_client [options]
 
 Options:
@@ -24,7 +40,7 @@ Options:
 
 ## Demo output
 
-```shell
+```sh
 zig build run -- -z Europe/Berlin
 ```
 
@@ -51,7 +67,7 @@ Round-trip delay:    0.077 s (76970 us)
 
 ## Compatibility and Requirements
 
-Developed & tested on Linux (Debian, on an x86 machine). Windows should work (build.zig links libc for this), Mac OS might work (can't test this).
+Developed & tested on Linux (Debian, on an x86 machine). Windows worked last time I tested (build.zig links libc for this), Mac OS might work (can't test this).
 
 ## Zig version
 

build.zig

@@ -1,59 +1,73 @@
 const std = @import("std");
 const log = std.log.scoped(.ntp_client_build);
-const client_version = std.SemanticVersion{ .major = 0, .minor = 0, .patch = 13 };
+const client_version = std.SemanticVersion{ .major = 0, .minor = 0, .patch = 14 };
 
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
+    // -Dexe option is required to build the executable.
+    // This avoids leaking dependencies, if another project wants to use
+    // ntp.zig as a library.
+    const build_exe = b.option(bool, "exe", "build executable");
+
     // expose ntp.zig as a library
     _ = b.addModule("ntp_client", .{
         .root_source_file = b.path("src/ntp.zig"),
     });
 
-    const flags = b.dependency("flags", .{});
-    const flags_module = flags.module("flags");
-
-    const zdt = b.dependency("zdt", .{
-        // use system zoneinfo:
-        //        .prefix_tzdb = @as([]const u8, "/usr/share/zoneinfo"),
-    });
-    const zdt_module = zdt.module("zdt");
-
-    const exe = b.addExecutable(.{
-        .name = "ntp_client",
-        .root_source_file = b.path("src/main.zig"),
-        .target = target,
-        .optimize = optimize,
-        .version = client_version,
-    });
+    if (build_exe) |_| {
+        const exe = b.addExecutable(.{
+            .name = "ntp_client",
+            .root_source_file = b.path("src/main.zig"),
+            .target = target,
+            .optimize = optimize,
+            .version = client_version,
+        });
 
-    b.installArtifact(exe);
+        b.installArtifact(exe);
 
-    // for Windows compatibility, required by sockets functionality
-    exe.linkLibC();
+        // for Windows compatibility, required by sockets functionality
+        exe.linkLibC();
 
-    exe.root_module.addImport("flags", flags_module);
-    exe.root_module.addImport("zdt", zdt_module);
+        // using lazy dependencies here so that another project can
+        // use the NTP lib without having to fetch flags and zdt
+        if (b.lazyDependency("flags", .{
+            .optimize = optimize,
+            .target = target,
+        })) |dep| {
+            exe.root_module.addImport("flags", dep.module("flags"));
+        }
+        if (b.lazyDependency("zdt", .{
+            .optimize = optimize,
+            .target = target,
+            // use system zoneinfo:
+            // .prefix_tzdb = @as([]const u8, "/usr/share/zoneinfo"),
+        })) |dep| {
+            exe.root_module.addImport("zdt", dep.module("zdt"));
+        }
 
-    const run_cmd = b.addRunArtifact(exe);
-    run_cmd.step.dependOn(b.getInstallStep());
+        const run_cmd = b.addRunArtifact(exe);
+        run_cmd.step.dependOn(b.getInstallStep());
 
-    if (b.args) |args| run_cmd.addArgs(args);
+        if (b.args) |args| run_cmd.addArgs(args);
 
-    const run_step = b.step("run", "Run the app");
-    run_step.dependOn(&run_cmd.step);
+        const run_step = b.step("run", "Run the app");
+        run_step.dependOn(&run_cmd.step);
+    }
 
+    // run unit tests from ntp.zig, which on its own has no dependencies
     const unit_tests = b.addTest(.{
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
     });
     const run_unit_tests = b.addRunArtifact(unit_tests);
-    //    run_unit_tests.has_side_effects = true;
     const test_step = b.step("test", "Run unit tests");
     test_step.dependOn(&run_unit_tests.step);
 
+    // autodocs step excluded since not really useful as NTP lib is currently
+    // pretty small.
     // const docs_step = b.step("docs", "auto-generate documentation");
     // {
     //     const install_docs = b.addInstallDirectory(.{

build.zig.zon

@@ -1,14 +1,16 @@
 .{
     .name = "ntp_client",
-    .version = "0.0.13",
+    .version = "0.0.14",
     .dependencies = .{
         .zdt = .{
             .url = "https://codeberg.org/FObersteiner/zdt/archive/v0.1.4.tar.gz",
             .hash = "122061d2677118a50e5692507e61e3a72189eb6ad08d7e90f699876f561627066677",
+            .lazy = true,
         },
         .flags = .{
             .url = "https://github.com/n0s4/flags/archive/refs/tags/v0.5.0.tar.gz",
             .hash = "12202e9d5de187569b77064c66a4972e8a824488295fab2f5c8cb48331eab9877257",
+            .lazy = true,
         },
     },
 

docs/change.log

@@ -1,5 +1,9 @@
 # Changelog
 
+## 2024-06-26, v0.0.14
+
+- use lazy dependencies so that another project can use ntp.zig without having to fetch the dependencies of this project
+
 ## 2024-06-24, v0.0.13
 
 - use parseIp instead of resolveIp, avoids "std.net.if_nametoindex unimplemented for this OS" error on specific OS (thanks @part1zano on codeberg)