Fixes #5669 - Enable chatCompletions experimental feature via CLI and ENV

https://www.meilisearch.com/docs/reference/api/chats#chat-completions-workspace-object
Currently the new `chatCompletions` feature could be enabled only via
```
curl \
  -X PATCH 'MEILISEARCH_URL/experimental-features/' \
  -H 'Content-Type: application/json' \
  --data-binary '{
    "chatCompletions": true
  }'
```

Now it will be possible to use
1) command line argument: `--experimental_chat_completions`
2) or environment variable:
   `export MEILI_EXPERIMENTAL_CHAT_COMPLETIONS=true`

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>

crates/meilisearch/src/analytics/segment_analytics.rs

@@ -279,6 +279,7 @@ impl Infos {
             indexer_options,
             config_file_path,
             no_analytics: _,
+            experimental_chat_completions: _,
         } = options;
 
         let schedule_snapshot = match schedule_snapshot {

crates/meilisearch/src/lib.rs

@@ -237,6 +237,7 @@ pub fn setup_meilisearch(opt: &Opt) -> anyhow::Result<(Arc<IndexScheduler>, Arc<
         auto_upgrade: opt.experimental_dumpless_upgrade,
         embedding_cache_cap: opt.experimental_embedding_cache_entries,
         experimental_no_snapshot_compaction: opt.experimental_no_snapshot_compaction,
+        experimental_chat_completions: opt.experimental_chat_completions,
     };
     let binary_version = (VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH);
 

crates/meilisearch/src/option.rs

@@ -66,6 +66,7 @@ const MEILI_EXPERIMENTAL_LIMIT_BATCHED_TASKS_TOTAL_SIZE: &str =
 const MEILI_EXPERIMENTAL_EMBEDDING_CACHE_ENTRIES: &str =
     "MEILI_EXPERIMENTAL_EMBEDDING_CACHE_ENTRIES";
 const MEILI_EXPERIMENTAL_NO_SNAPSHOT_COMPACTION: &str = "MEILI_EXPERIMENTAL_NO_SNAPSHOT_COMPACTION";
+const MEILI_EXPERIMENTAL_CHAT_COMPLETIONS: &str = "MEILI_EXPERIMENTAL_CHAT_COMPLETIONS";
 const DEFAULT_CONFIG_FILE_PATH: &str = "./config.toml";
 const DEFAULT_DB_PATH: &str = "./data.ms";
 const DEFAULT_HTTP_ADDR: &str = "localhost:7700";
@@ -473,6 +474,11 @@ pub struct Opt {
     /// Format must be TOML.
     #[clap(long)]
     pub config_file_path: Option<PathBuf>,
+
+    /// Enables the chat completions functionality.
+    #[serde(default)]
+    #[clap(long, env = MEILI_EXPERIMENTAL_CHAT_COMPLETIONS, default_value_t = false)]
+    pub experimental_chat_completions: bool,
 }
 
 impl Opt {
@@ -498,25 +504,21 @@ impl Opt {
             Ok(config) => {
                 // If the file is successfully read, we deserialize it with `toml`.
                 let opt_from_config = toml::from_str::<Opt>(&config)?;
-                // Return an error if config file contains 'config_file_path'
+                // Return an error if the config file contains 'config_file_path'
                 // Using that key in the config file doesn't make sense bc it creates a logical loop (config file referencing itself)
                 if opt_from_config.config_file_path.is_some() {
                     anyhow::bail!("`config_file_path` is not supported in the configuration file")
                 }
                 // We inject the values from the toml in the corresponding env vars if needs be. Doing so, we respect the priority toml < env vars < cli args.
                 opt_from_config.export_to_env();
-                // Once injected we parse the cli args once again to take the new env vars into scope.
+                // Once injected, we parse the cli args once again to take the new env vars into scope.
                 opts = Opt::parse();
                 config_read_from = Some(config_file_path);
             }
             Err(e) => {
                 if let Some(path) = user_specified_config_file_path {
                     // If we have an error while reading the file defined by the user.
-                    anyhow::bail!(
-                        "unable to open or read the {:?} configuration file: {}.",
-                        path,
-                        e,
-                    )
+                    anyhow::bail!("unable to open or read the {path:?} configuration file: {e}.")
                 }
             }
         }
@@ -570,6 +572,7 @@ impl Opt {
             experimental_limit_batched_tasks_total_size,
             experimental_embedding_cache_entries,
             experimental_no_snapshot_compaction,
+            experimental_chat_completions,
         } = self;
         export_to_env_if_not_present(MEILI_DB_PATH, db_path);
         export_to_env_if_not_present(MEILI_HTTP_ADDR, http_addr);
@@ -670,6 +673,10 @@ impl Opt {
             MEILI_EXPERIMENTAL_NO_SNAPSHOT_COMPACTION,
             experimental_no_snapshot_compaction.to_string(),
         );
+        export_to_env_if_not_present(
+            MEILI_EXPERIMENTAL_CHAT_COMPLETIONS,
+            experimental_chat_completions.to_string(),
+        );
         indexer_options.export_to_env();
     }