Use enum-typed PG versions (#12317)

This makes it possible for the compiler to validate that a match block
matched all PostgreSQL versions we support.

## Problem
We did not have a complete picture about which places we had to test
against PG versions, and what format these versions were: The full PG
version ID format (Major/minor/bugfix `MMmmbb`) as transfered in
protocol messages, or only the Major release version (`MM`). This meant
type confusion was rampant.

With this change, it becomes easier to develop new version-dependent
features, by making type and niche confusion impossible.

## Summary of changes
Every use of `pg_version` is now typed as either `PgVersionId` (u32,
valued in decimal `MMmmbb`) or PgMajorVersion (an enum, with a value for
every major version we support, serialized and stored like a u32 with
the value of that major version)

---------

Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>

control_plane/src/bin/neon_local.rs

@@ -48,7 +48,7 @@ use postgres_connection::parse_host_port;
 use safekeeper_api::membership::{SafekeeperGeneration, SafekeeperId};
 use safekeeper_api::{
     DEFAULT_HTTP_LISTEN_PORT as DEFAULT_SAFEKEEPER_HTTP_PORT,
-    DEFAULT_PG_LISTEN_PORT as DEFAULT_SAFEKEEPER_PG_PORT,
+    DEFAULT_PG_LISTEN_PORT as DEFAULT_SAFEKEEPER_PG_PORT, PgMajorVersion, PgVersionId,
 };
 use storage_broker::DEFAULT_LISTEN_ADDR as DEFAULT_BROKER_ADDR;
 use tokio::task::JoinSet;
@@ -64,7 +64,7 @@ const DEFAULT_PAGESERVER_ID: NodeId = NodeId(1);
 const DEFAULT_BRANCH_NAME: &str = "main";
 project_git_version!(GIT_VERSION);
 
-const DEFAULT_PG_VERSION: u32 = 17;
+const DEFAULT_PG_VERSION: PgMajorVersion = PgMajorVersion::PG17;
 
 const DEFAULT_PAGESERVER_CONTROL_PLANE_API: &str = "http://127.0.0.1:1234/upcall/v1/";
 
@@ -169,7 +169,7 @@ struct TenantCreateCmdArgs {
 
     #[arg(default_value_t = DEFAULT_PG_VERSION)]
     #[clap(long, help = "Postgres version to use for the initial timeline")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 
     #[clap(
         long,
@@ -292,7 +292,7 @@ struct TimelineCreateCmdArgs {
 
     #[arg(default_value_t = DEFAULT_PG_VERSION)]
     #[clap(long, help = "Postgres version")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 }
 
 #[derive(clap::Args)]
@@ -324,7 +324,7 @@ struct TimelineImportCmdArgs {
 
     #[arg(default_value_t = DEFAULT_PG_VERSION)]
     #[clap(long, help = "Postgres version of the backup being imported")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 }
 
 #[derive(clap::Subcommand)]
@@ -603,7 +603,7 @@ struct EndpointCreateCmdArgs {
 
     #[arg(default_value_t = DEFAULT_PG_VERSION)]
     #[clap(long, help = "Postgres version")]
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 
     /// Use gRPC to communicate with Pageservers, by generating grpc:// connstrings.
     ///
@@ -1295,7 +1295,7 @@ async fn handle_timeline(cmd: &TimelineCmd, env: &mut local_env::LocalEnv) -> Re
                     },
                     new_members: None,
                 };
-                let pg_version = args.pg_version * 10000;
+                let pg_version = PgVersionId::from(args.pg_version);
                 let req = safekeeper_api::models::TimelineCreateRequest {
                     tenant_id,
                     timeline_id,

control_plane/src/endpoint.rs

@@ -67,6 +67,7 @@ use nix::sys::signal::{Signal, kill};
 use pageserver_api::shard::ShardStripeSize;
 use pem::Pem;
 use reqwest::header::CONTENT_TYPE;
+use safekeeper_api::PgMajorVersion;
 use safekeeper_api::membership::SafekeeperGeneration;
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
@@ -89,7 +90,7 @@ pub struct EndpointConf {
     pg_port: u16,
     external_http_port: u16,
     internal_http_port: u16,
-    pg_version: u32,
+    pg_version: PgMajorVersion,
     grpc: bool,
     skip_pg_catalog_updates: bool,
     reconfigure_concurrency: usize,
@@ -192,7 +193,7 @@ impl ComputeControlPlane {
         pg_port: Option<u16>,
         external_http_port: Option<u16>,
         internal_http_port: Option<u16>,
-        pg_version: u32,
+        pg_version: PgMajorVersion,
         mode: ComputeMode,
         grpc: bool,
         skip_pg_catalog_updates: bool,
@@ -312,7 +313,7 @@ pub struct Endpoint {
     pub internal_http_address: SocketAddr,
 
     // postgres major version in the format: 14, 15, etc.
-    pg_version: u32,
+    pg_version: PgMajorVersion,
 
     // These are not part of the endpoint as such, but the environment
     // the endpoint runs in.
@@ -557,7 +558,7 @@ impl Endpoint {
                 conf.append("hot_standby", "on");
                 // prefetching of blocks referenced in WAL doesn't make sense for us
                 // Neon hot standby ignores pages that are not in the shared_buffers
-                if self.pg_version >= 15 {
+                if self.pg_version >= PgMajorVersion::PG15 {
                     conf.append("recovery_prefetch", "off");
                 }
             }

control_plane/src/local_env.rs

@@ -15,6 +15,7 @@ use clap::ValueEnum;
 use pem::Pem;
 use postgres_backend::AuthType;
 use reqwest::{Certificate, Url};
+use safekeeper_api::PgMajorVersion;
 use serde::{Deserialize, Serialize};
 use utils::auth::encode_from_key_file;
 use utils::id::{NodeId, TenantId, TenantTimelineId, TimelineId};
@@ -424,25 +425,21 @@ impl LocalEnv {
         self.pg_distrib_dir.clone()
     }
 
-    pub fn pg_distrib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_distrib_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
         let path = self.pg_distrib_dir.clone();
 
-        #[allow(clippy::manual_range_patterns)]
-        match pg_version {
-            14 | 15 | 16 | 17 => Ok(path.join(format!("v{pg_version}"))),
-            _ => bail!("Unsupported postgres version: {}", pg_version),
-        }
+        Ok(path.join(pg_version.v_str()))
     }
 
-    pub fn pg_dir(&self, pg_version: u32, dir_name: &str) -> anyhow::Result<PathBuf> {
+    pub fn pg_dir(&self, pg_version: PgMajorVersion, dir_name: &str) -> anyhow::Result<PathBuf> {
         Ok(self.pg_distrib_dir(pg_version)?.join(dir_name))
     }
 
-    pub fn pg_bin_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_bin_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
         self.pg_dir(pg_version, "bin")
     }
 
-    pub fn pg_lib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_lib_dir(&self, pg_version: PgMajorVersion) -> anyhow::Result<PathBuf> {
         self.pg_dir(pg_version, "lib")
     }
 

control_plane/src/pageserver.rs

@@ -22,6 +22,7 @@ use pageserver_api::shard::TenantShardId;
 use pageserver_client::mgmt_api;
 use postgres_backend::AuthType;
 use postgres_connection::{PgConnectionConfig, parse_host_port};
+use safekeeper_api::PgMajorVersion;
 use utils::auth::{Claims, Scope};
 use utils::id::{NodeId, TenantId, TimelineId};
 use utils::lsn::Lsn;
@@ -607,7 +608,7 @@ impl PageServerNode {
         timeline_id: TimelineId,
         base: (Lsn, PathBuf),
         pg_wal: Option<(Lsn, PathBuf)>,
-        pg_version: u32,
+        pg_version: PgMajorVersion,
     ) -> anyhow::Result<()> {
         // Init base reader
         let (start_lsn, base_tarfile_path) = base;

control_plane/src/storage_controller.rs

@@ -6,6 +6,8 @@ use std::str::FromStr;
 use std::sync::OnceLock;
 use std::time::{Duration, Instant};
 
+use crate::background_process;
+use crate::local_env::{LocalEnv, NeonStorageControllerConf};
 use camino::{Utf8Path, Utf8PathBuf};
 use hyper0::Uri;
 use nix::unistd::Pid;
@@ -22,6 +24,7 @@ use pageserver_client::mgmt_api::ResponseErrorMessageExt;
 use pem::Pem;
 use postgres_backend::AuthType;
 use reqwest::{Method, Response};
+use safekeeper_api::PgMajorVersion;
 use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use tokio::process::Command;
@@ -31,9 +34,6 @@ use utils::auth::{Claims, Scope, encode_from_key_file};
 use utils::id::{NodeId, TenantId};
 use whoami::username;
 
-use crate::background_process;
-use crate::local_env::{LocalEnv, NeonStorageControllerConf};
-
 pub struct StorageController {
     env: LocalEnv,
     private_key: Option<Pem>,
@@ -48,7 +48,7 @@ pub struct StorageController {
 
 const COMMAND: &str = "storage_controller";
 
-const STORAGE_CONTROLLER_POSTGRES_VERSION: u32 = 16;
+const STORAGE_CONTROLLER_POSTGRES_VERSION: PgMajorVersion = PgMajorVersion::PG16;
 
 const DB_NAME: &str = "storage_controller";
 
@@ -184,9 +184,15 @@ impl StorageController {
     /// to other versions if that one isn't found.  Some automated tests create circumstances
     /// where only one version is available in pg_distrib_dir, such as `test_remote_extensions`.
     async fn get_pg_dir(&self, dir_name: &str) -> anyhow::Result<Utf8PathBuf> {
-        let prefer_versions = [STORAGE_CONTROLLER_POSTGRES_VERSION, 16, 15, 14];
+        const PREFER_VERSIONS: [PgMajorVersion; 5] = [
+            STORAGE_CONTROLLER_POSTGRES_VERSION,
+            PgMajorVersion::PG16,
+            PgMajorVersion::PG15,
+            PgMajorVersion::PG14,
+            PgMajorVersion::PG17,
+        ];
 
-        for v in prefer_versions {
+        for v in PREFER_VERSIONS {
             let path = Utf8PathBuf::from_path_buf(self.env.pg_dir(v, dir_name)?).unwrap();
             if tokio::fs::try_exists(&path).await? {
                 return Ok(path);