Merge #3467

3467: Identify builds git tagged with `prototype-...` in CLI and analytics r=curquiza a=dureuill

# Pull Request

## What does this PR do?

- Parses the last git tag to extract a prototype name if:
  - Current build uses the prototype tag (not after the tag) precisely
  - The prototype tag name respects the following conditions:
    1. starts with `prototype-`
    2. ends with a number
    3. the hyphen-separated segment right before the number is not a number (required to reject commits after the tag).
- Display the prototype name in the launch summary in the CLI
- Send the prototype name to analytics if any
- Update prototypes instructions in CONTRIBUTING.md

|`VERGEN_GIT_SEMVER_LIGHTWEIGHT` value | Prototype |
|---|---|
| `Some("prototype-geo-bounding-box-0-139-gcde89018")` | `None` (does not end with a number) |
| `Some("prototype-geo-bounding-box-0-139-89018")` | `None` (before the last segment is a number) |
| `Some("prototype-geo-bounding-box-0")` | `Some("prototype-geo-bounding-box-0")` |
| `Some("prototype-geo-bounding-box")` | `None` (does not end with a number") |
| `Some("geo-bounding-box-0")` | `None` (does not start with "prototype") |
| `None` | `None` | 

Co-authored-by: Louis Dureuil <louis@meilisearch.com>

meilisearch/build.rs

@@ -1,7 +1,14 @@
-use vergen::{vergen, Config};
+use vergen::{vergen, Config, SemverKind};
 
 fn main() {
-    if let Err(e) = vergen(Config::default()) {
+    // Note: any code that needs VERGEN_ environment variables should take care to define them manually in the Dockerfile and pass them
+    // in the corresponding GitHub workflow (publish_docker.yml).
+    // This is due to the Dockerfile building the binary outside of the git directory.
+    let mut config = Config::default();
+    // allow using non-annotated tags
+    *config.git_mut().semver_kind_mut() = SemverKind::Lightweight;
+
+    if let Err(e) = vergen(config) {
         println!("cargo:warning=vergen: {}", e);
     }
 

meilisearch/src/analytics/segment_analytics.rs

@@ -401,12 +401,19 @@ impl Segment {
         if let Ok(stats) =
             create_all_stats(index_scheduler.into(), auth_controller, &SearchRules::default())
         {
+            // Replace the version number with the prototype name if any.
+            let version = if let Some(prototype) = crate::prototype_name() {
+                prototype
+            } else {
+                env!("CARGO_PKG_VERSION")
+            };
+
             let _ = self
                 .batcher
                 .push(Identify {
                     context: Some(json!({
                         "app": {
-                            "version": env!("CARGO_PKG_VERSION").to_string(),
+                            "version": version.to_string(),
                         },
                     })),
                     user: self.user.clone(),

meilisearch/src/lib.rs

@@ -427,3 +427,30 @@ pub fn configure_metrics_route(config: &mut web::ServiceConfig, enable_metrics_r
         );
     }
 }
+
+/// Parses the output of
+/// [`VERGEN_GIT_SEMVER_LIGHTWEIGHT`](https://docs.rs/vergen/latest/vergen/struct.Git.html#instructions)
+///  as a prototype name.
+///
+/// Returns `Some(prototype_name)` if the following conditions are met on this value:
+///
+/// 1. starts with `prototype-`,
+/// 2. ends with `-<some_number>`,
+/// 3. does not end with `<some_number>-<some_number>`.
+///
+/// Otherwise, returns `None`.
+pub fn prototype_name() -> Option<&'static str> {
+    let prototype: &'static str = option_env!("VERGEN_GIT_SEMVER_LIGHTWEIGHT")?;
+
+    if !prototype.starts_with("prototype-") {
+        return None;
+    }
+
+    let mut rsplit_prototype = prototype.rsplit('-');
+    // last component MUST be a number
+    rsplit_prototype.next()?.parse::<u64>().ok()?;
+    // before than last component SHALL NOT be a number
+    rsplit_prototype.next()?.parse::<u64>().err()?;
+
+    Some(prototype)
+}

meilisearch/src/main.rs

@@ -8,7 +8,7 @@ use actix_web::web::Data;
 use actix_web::HttpServer;
 use index_scheduler::IndexScheduler;
 use meilisearch::analytics::Analytics;
-use meilisearch::{analytics, create_app, setup_meilisearch, Opt};
+use meilisearch::{analytics, create_app, prototype_name, setup_meilisearch, Opt};
 use meilisearch_auth::{generate_master_key, AuthController, MASTER_KEY_MIN_SIZE};
 use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
@@ -137,6 +137,9 @@ pub fn print_launch_resume(
     eprintln!("Commit SHA:\t\t{:?}", commit_sha.to_string());
     eprintln!("Commit date:\t\t{:?}", commit_date.to_string());
     eprintln!("Package version:\t{:?}", env!("CARGO_PKG_VERSION").to_string());
+    if let Some(prototype) = prototype_name() {
+        eprintln!("Prototype:\t\t{:?}", prototype);
+    }
 
     #[cfg(all(not(debug_assertions), feature = "analytics"))]
     {