[pdm-devel] [PATCH datacenter-manager v2 09/14] config: add auto-installer configuration module

[Christoph Heiss]

Provides some primitives for the auto-installer integration to save
state about
- individual installations (as plain JSON, as these aren't
  configurations files) and
- prepared answer file configurations, as section config

The new files (including lock files) are placed under
`/etc/proxmox-datacenter-manager/autoinst`.

Signed-off-by: Christoph Heiss <c.heiss at proxmox.com>
---
Changes v1 -> v2:
  * no changes

 lib/pdm-config/Cargo.toml          |  2 +
 lib/pdm-config/src/auto_install.rs | 85 ++++++++++++++++++++++++++++++
 lib/pdm-config/src/lib.rs          |  1 +
 lib/pdm-config/src/setup.rs        |  7 +++
 4 files changed, 95 insertions(+)
 create mode 100644 lib/pdm-config/src/auto_install.rs

diff --git a/lib/pdm-config/Cargo.toml b/lib/pdm-config/Cargo.toml
index d39c2ad..c43579d 100644
--- a/lib/pdm-config/Cargo.toml
+++ b/lib/pdm-config/Cargo.toml
@@ -12,6 +12,7 @@ nix.workspace = true
 once_cell.workspace = true
 openssl.workspace = true
 serde.workspace = true
+serde_json.workspace = true
 
 proxmox-config-digest = { workspace = true, features = [ "openssl" ] }
 proxmox-http = { workspace = true, features = [ "http-helpers" ] }
@@ -23,5 +24,6 @@ proxmox-shared-memory.workspace = true
 proxmox-simple-config.workspace = true
 proxmox-sys = { workspace = true, features = [ "acl", "crypt", "timer" ] }
 proxmox-acme-api.workspace = true
+proxmox-serde.workspace = true
 pdm-api-types.workspace = true
 pdm-buildcfg.workspace = true
diff --git a/lib/pdm-config/src/auto_install.rs b/lib/pdm-config/src/auto_install.rs
new file mode 100644
index 0000000..0374a70
--- /dev/null
+++ b/lib/pdm-config/src/auto_install.rs
@@ -0,0 +1,85 @@
+//! Implements configuration for the auto-installer integration.
+
+use anyhow::Result;
+use proxmox_schema::ApiType;
+use proxmox_section_config::{SectionConfig, SectionConfigData, SectionConfigPlugin};
+use std::{fs::File, sync::LazyLock};
+
+use pdm_api_types::{
+    auto_installer::{Installation, PreparedInstallationConfig, PREPARED_INSTALL_CONFIG_ID_SCHEMA},
+    ConfigDigest,
+};
+use proxmox_product_config::{open_api_lockfile, replace_config, ApiLockGuard};
+use proxmox_sys::error::SysError;
+
+pub const CONFIG_PATH: &str = pdm_buildcfg::configdir!("/autoinst");
+
+static CONFIG: LazyLock<SectionConfig> = LazyLock::new(|| {
+    let mut config = SectionConfig::new(&PREPARED_INSTALL_CONFIG_ID_SCHEMA);
+
+    config.register_plugin(SectionConfigPlugin::new(
+        "prepared-answer".into(),
+        Some("id".into()),
+        PreparedInstallationConfig::API_SCHEMA.unwrap_object_schema(),
+    ));
+    config
+});
+
+const PREPARED_CONF_FILE: &str = pdm_buildcfg::configdir!("/autoinst/prepared.cfg");
+const PREPARED_LOCK_FILE: &str = pdm_buildcfg::configdir!("/autoinst/.prepared.lock");
+
+// Information about installations themselves are not configuration files and thus are saved
+// as JSON.
+const INSTALLATIONS_CONF_FILE: &str = pdm_buildcfg::configdir!("/autoinst/installations.json");
+const INSTALLATIONS_LOCK_FILE: &str = pdm_buildcfg::configdir!("/autoinst/.installations.lock");
+
+pub fn installations_read_lock() -> Result<ApiLockGuard> {
+    open_api_lockfile(INSTALLATIONS_LOCK_FILE, None, false)
+}
+
+pub fn installations_write_lock() -> Result<ApiLockGuard> {
+    open_api_lockfile(INSTALLATIONS_LOCK_FILE, None, true)
+}
+
+pub fn read_installations() -> Result<(Vec<Installation>, ConfigDigest)> {
+    let content: serde_json::Value = match File::open(INSTALLATIONS_CONF_FILE) {
+        Ok(file) => serde_json::from_reader(std::io::BufReader::new(file))?,
+        Err(ref err) if err.not_found() => serde_json::json!([]),
+        Err(err) => return Err(err.into()),
+    };
+
+    let digest = proxmox_serde::json::to_canonical_json(&content).map(ConfigDigest::from_slice)?;
+    let data = serde_json::from_value(content)?;
+
+    Ok((data, digest))
+}
+
+/// Write lock must be already held.
+pub fn save_installations(config: &[Installation]) -> Result<()> {
+    let raw = serde_json::to_string(&config)?;
+    replace_config(INSTALLATIONS_CONF_FILE, raw.as_bytes())
+}
+
+pub fn prepared_answers_read_lock() -> Result<ApiLockGuard> {
+    open_api_lockfile(PREPARED_LOCK_FILE, None, false)
+}
+
+pub fn prepared_answers_write_lock() -> Result<ApiLockGuard> {
+    open_api_lockfile(PREPARED_LOCK_FILE, None, true)
+}
+
+pub fn read_prepared_answers() -> Result<(SectionConfigData, ConfigDigest)> {
+    let content =
+        proxmox_sys::fs::file_read_optional_string(PREPARED_CONF_FILE)?.unwrap_or_default();
+
+    let digest = ConfigDigest::from_slice(content.as_bytes());
+    let data = CONFIG.parse(PREPARED_CONF_FILE, &content)?;
+
+    Ok((data, digest))
+}
+
+/// Write lock must be already held.
+pub fn save_prepared_answers(config: &SectionConfigData) -> Result<()> {
+    let raw = CONFIG.write(PREPARED_CONF_FILE, config)?;
+    replace_config(PREPARED_CONF_FILE, raw.as_bytes())
+}
diff --git a/lib/pdm-config/src/lib.rs b/lib/pdm-config/src/lib.rs
index 4c49054..5b9bcca 100644
--- a/lib/pdm-config/src/lib.rs
+++ b/lib/pdm-config/src/lib.rs
@@ -2,6 +2,7 @@ use anyhow::{format_err, Error};
 use nix::unistd::{Gid, Group, Uid, User};
 pub use pdm_buildcfg::{BACKUP_GROUP_NAME, BACKUP_USER_NAME};
 
+pub mod auto_install;
 pub mod certificate_config;
 pub mod domains;
 pub mod node;
diff --git a/lib/pdm-config/src/setup.rs b/lib/pdm-config/src/setup.rs
index 5f920c8..5adb05f 100644
--- a/lib/pdm-config/src/setup.rs
+++ b/lib/pdm-config/src/setup.rs
@@ -24,6 +24,13 @@ pub fn create_configdir() -> Result<(), Error> {
         0o750,
     )?;
 
+    mkdir_perms(
+        crate::auto_install::CONFIG_PATH,
+        api_user.uid,
+        api_user.gid,
+        0o750,
+    )?;
+
     Ok(())
 }
 
-- 
2.51.2