wip: FailoverTopology implementation for PostgreSQL on the way!

harmony/src/domain/topology/failover.rs

@@ -0,0 +1,141 @@
+use async_trait::async_trait;
+
+use log::{debug, info};
+use std::collections::HashMap;
+
+use crate::{
+    modules::postgresql::capability::{
+        BootstrapConfig, BootstrapStrategy, ExternalClusterConfig, PostgreSQL,
+        PostgreSQLClusterRole, PostgreSQLConfig, PostgreSQLEndpoint, ReplicaConfig,
+        ReplicationCerts,
+    },
+    topology::{PreparationError, PreparationOutcome, Topology},
+};
+
+pub struct FailoverTopology<T> {
+    primary: T,
+    replica: T,
+}
+
+#[async_trait]
+impl<T: Send + Sync> Topology for FailoverTopology<T> {
+    fn name(&self) -> &str {
+        "FailoverTopology"
+    }
+
+    async fn ensure_ready(&self) -> Result<PreparationOutcome, PreparationError> {
+        todo!()
+    }
+}
+
+#[async_trait]
+impl<T: PostgreSQL> PostgreSQL for FailoverTopology<T> {
+    async fn deploy(&self, config: &PostgreSQLConfig) -> Result<String, String> {
+        info!(
+            "Starting deployment of failover topology '{}'",
+            config.cluster_name
+        );
+
+        let primary_config = PostgreSQLConfig {
+            cluster_name: config.cluster_name.clone(),
+            instances: config.instances,
+            storage_size: config.storage_size.clone(),
+            role: PostgreSQLClusterRole::Primary,
+        };
+
+        info!(
+            "Deploying primary cluster '{{}}' ({} instances, {:?} storage)",
+            primary_config.cluster_name, primary_config.storage_size
+        );
+
+        let primary_cluster_name = self.primary.deploy(&primary_config).await?;
+
+        info!("Primary cluster '{primary_cluster_name}' deployed successfully");
+
+        info!("Retrieving replication certificates for primary '{primary_cluster_name}'");
+
+        let certs = self
+            .primary
+            .get_replication_certs(&primary_cluster_name)
+            .await?;
+
+        info!("Replication certificates retrieved successfully");
+
+        info!("Retrieving public endpoint for primary '{primary_cluster_name}");
+
+        let endpoint = self
+            .primary
+            .get_public_endpoint(&primary_cluster_name)
+            .await?
+            .ok_or_else(|| "No public endpoint configured on primary cluster".to_string())?;
+
+        info!(
+            "Public endpoint '{}:{}' retrieved for primary",
+            endpoint.host, endpoint.port
+        );
+
+        info!("Configuring replica connection parameters and bootstrap");
+
+        let mut connection_parameters = HashMap::new();
+        connection_parameters.insert("host".to_string(), endpoint.host);
+        connection_parameters.insert("port".to_string(), endpoint.port.to_string());
+        connection_parameters.insert("dbname".to_string(), "postgres".to_string());
+        connection_parameters.insert("user".to_string(), "streaming_replica".to_string());
+        connection_parameters.insert("sslmode".to_string(), "verify-ca".to_string());
+        connection_parameters.insert("sslnegotiation".to_string(), "direct".to_string());
+
+        debug!("Replica connection parameters: {:?}", connection_parameters);
+
+        let external_cluster = ExternalClusterConfig {
+            name: primary_cluster_name.clone(),
+            connection_parameters,
+        };
+
+        let bootstrap_config = BootstrapConfig {
+            strategy: BootstrapStrategy::PgBasebackup,
+        };
+
+        let replica_cluster_config = ReplicaConfig {
+            primary_cluster_name: primary_cluster_name.clone(),
+            replication_certs: certs,
+            bootstrap: bootstrap_config,
+            external_cluster,
+        };
+
+        let replica_config = PostgreSQLConfig {
+            cluster_name: format!("{}-replica", primary_cluster_name),
+            instances: config.instances,
+            storage_size: config.storage_size.clone(),
+            role: PostgreSQLClusterRole::Replica(replica_cluster_config),
+        };
+
+        info!(
+            "Deploying replica cluster '{}' ({} instances, {:?} storage) on replica topology",
+            replica_config.cluster_name, replica_config.instances, replica_config.storage_size
+        );
+
+        self.replica.deploy(&replica_config).await?;
+
+        info!(
+            "Replica cluster '{}' deployed successfully; failover topology '{}' ready",
+            replica_config.cluster_name, config.cluster_name
+        );
+
+        Ok(primary_cluster_name)
+    }
+
+    async fn get_replication_certs(&self, cluster_name: &str) -> Result<ReplicationCerts, String> {
+        self.primary.get_replication_certs(cluster_name).await
+    }
+
+    async fn get_endpoint(&self, cluster_name: &str) -> Result<PostgreSQLEndpoint, String> {
+        self.primary.get_endpoint(cluster_name).await
+    }
+
+    async fn get_public_endpoint(
+        &self,
+        cluster_name: &str,
+    ) -> Result<Option<PostgreSQLEndpoint>, String> {
+        self.primary.get_public_endpoint(cluster_name).await
+    }
+}

harmony/src/domain/topology/mod.rs

@@ -1,5 +1,7 @@
 mod ha_cluster;
 pub mod ingress;
+mod failover;
+pub use failover::*;
 use harmony_types::net::IpAddress;
 mod host_binding;
 mod http;

harmony/src/modules/mod.rs

@@ -17,3 +17,4 @@ pub mod prometheus;
 pub mod storage;
 pub mod tenant;
 pub mod tftp;
+pub mod postgresql;

harmony/src/modules/postgresql/capability.rs

@@ -0,0 +1,81 @@
+use async_trait::async_trait;
+use harmony_types::storage::StorageSize;
+use std::collections::HashMap;
+
+#[async_trait]
+pub trait PostgreSQL {
+    async fn deploy(&self, config: &PostgreSQLConfig) -> Result<String, String>;
+
+    /// Extracts PostgreSQL-specific replication certs (PEM format) from a deployed primary cluster.
+    /// Abstracts away storage/retrieval details (e.g., secrets, files).
+    async fn get_replication_certs(&self, cluster_name: &str) -> Result<ReplicationCerts, String>;
+
+    /// Gets the internal/private endpoint (e.g., k8s service FQDN:5432) for the cluster.
+    async fn get_endpoint(&self, cluster_name: &str) -> Result<PostgreSQLEndpoint, String>;
+
+    /// Gets the public/externally routable endpoint if configured (e.g., OKD Route:443 for TLS passthrough).
+    /// Returns None if no public endpoint (internal-only cluster).
+    /// UNSTABLE: This is opinionated for initial multisite use cases. Networking abstraction is complex
+    /// (cf. k8s Ingress -> Gateway API evolution); may move to higher-order Networking/PostgreSQLNetworking trait.
+    async fn get_public_endpoint(&self, cluster_name: &str) -> Result<Option<PostgreSQLEndpoint>, String>;
+}
+
+#[derive(Clone, Debug)]
+pub struct PostgreSQLConfig {
+    pub cluster_name: String,
+    pub instances: u32,
+    pub storage_size: StorageSize,
+    pub role: PostgreSQLClusterRole,
+}
+
+#[derive(Clone, Debug)]
+pub enum PostgreSQLClusterRole {
+    Primary,
+    Replica(ReplicaClusterConfig),
+}
+
+#[derive(Clone, Debug)]
+pub struct ReplicaConfig {
+    /// Name of the primary cluster this replica will sync from
+    pub primary_cluster_name: String,
+    /// Certs extracted from primary via Topology::get_replication_certs()
+    pub replication_certs: ReplicationCerts,
+    /// Bootstrap method (e.g., pg_basebackup from primary)
+    pub bootstrap: BootstrapConfig,
+    /// External cluster connection details for CNPG spec.externalClusters
+    pub external_cluster: ExternalClusterConfig,
+}
+
+#[derive(Clone, Debug)]
+pub struct BootstrapConfig {
+    pub strategy: BootstrapStrategy,
+}
+
+#[derive(Clone, Debug)]
+pub enum BootstrapStrategy {
+    PgBasebackup,
+}
+
+#[derive(Clone, Debug)]
+pub struct ExternalClusterConfig {
+    /// Name used in CNPG externalClusters list
+    pub name: String,
+    /// Connection params (host/port set by multisite logic, sslmode='verify-ca', etc.)
+    pub connection_parameters: HashMap<String, String>,
+}
+
+#[derive(Clone, Debug)]
+pub struct ReplicationCerts {
+    /// PEM-encoded CA cert from primary
+    pub ca_cert_pem: String,
+    /// PEM-encoded streaming_replica client cert (tls.crt)
+    pub streaming_replica_cert_pem: String,
+    /// PEM-encoded streaming_replica client key (tls.key)
+    pub streaming_replica_key_pem: String,
+}
+
+#[derive(Clone, Debug)]
+pub struct PostgreSQLEndpoint {
+    pub host: String,
+    pub port: u16,
+}

harmony/src/modules/postgresql/mod.rs

@@ -0,0 +1,7 @@
+
+pub mod capability;
+mod score;
+
+
+pub mod failover;
+

harmony/src/modules/postgresql/score.rs

@@ -0,0 +1,236 @@
+use crate::{
+    domain::{data::Version, interpret::InterpretStatus},
+    interpret::{Interpret, InterpretError, InterpretName, Outcome},
+    inventory::Inventory,
+    modules::postgresql::capability::PostgreSQL,
+    score::Score,
+    topology::Topology,
+};
+
+use super::capability::*;
+
+use derive_new::new;
+use harmony_types::{id::Id, storage::StorageSize};
+
+use async_trait::async_trait;
+use log::info;
+use serde::Serialize;
+
+pub struct PostgreSQLScore {
+    config: PostgreSQLConfig,
+}
+
+#[derive(Debug, Clone)]
+pub struct PostgreSQLInterpret {
+    config: PostgreSQLConfig,
+    version: Version,
+    status: InterpretStatus,
+}
+
+impl PostgreSQLInterpret {
+    pub fn new(config: PostgreSQLConfig) -> Self {
+        let version = Version::from("1.0.0").expect("Version should be valid");
+        Self {
+            config,
+            version,
+            status: InterpretStatus::QUEUED,
+        }
+    }
+}
+
+impl<T: Topology + PostgreSQL> Score<T> for PostgreSQLScore {
+    fn name(&self) -> String {
+        "PostgreSQLScore".to_string()
+    }
+
+    fn create_interpret(&self) -> Box<dyn Interpret<T>> {
+        Box::new(PostgreSQLInterpret::new(self.config.clone()))
+    }
+}
+
+#[async_trait]
+impl<T: Topology + PostgreSQL> Interpret<T> for PostgreSQLInterpret {
+    fn get_name(&self) -> InterpretName {
+        InterpretName::Custom("PostgreSQLInterpret")
+    }
+
+    fn get_version(&self) -> crate::domain::data::Version {
+        self.version.clone()
+    }
+
+    fn get_status(&self) -> InterpretStatus {
+        self.status.clone()
+    }
+
+    fn get_children(&self) -> Vec<Id> {
+        todo!()
+    }
+
+    async fn execute(
+        &self,
+        _inventory: &Inventory,
+        topology: &T,
+    ) -> Result<Outcome, InterpretError> {
+        info!(
+            "Executing PostgreSQLInterpret with config {:?}",
+            self.config
+        );
+
+        let cluster_name = topology
+            .deploy(&self.config)
+            .await
+            .map_err(|e| InterpretError::from(e))?;
+
+        Ok(Outcome::success(format!(
+            "Deployed PostgreSQL cluster `{cluster_name}`"
+        )))
+    }
+}
+
+#[derive(Debug, new, Clone, Serialize)]
+pub struct MultisitePostgreSQLScore {
+    pub cluster_name: String,
+    pub primary_site: Id,
+    pub replica_sites: Vec<Id>,
+    pub instances: u32,
+    pub storage_size: StorageSize,
+}
+
+impl<T: FailoverTopology + crate::modules::postgresql::capability::PostgreSQL> Score<T> for MultisitePostgreSQLScore {
+
+    fn create_interpret(&self) -> Box<dyn Interpret<T>> {
+        Box::new(MultisitePostgreSQLInterpret::new(self.clone()))
+    }
+
+    fn name(&self) -> String {
+        "MultisitePostgreSQLScore".to_string()
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct MultisitePostgreSQLInterpret {
+    score: MultisitePostgreSQLScore,
+    version: Version,
+    status: InterpretStatus,
+}
+
+impl MultisitePostgreSQLInterpret {
+    pub fn new(score: MultisitePostgreSQLScore) -> Self {
+        let version = Version::from("1.0.0").expect("Version should be valid");
+        Self {
+            score,
+            version,
+            status: InterpretStatus::QUEUED,
+        }
+    }
+}
+
+#[async_trait]
+impl<T: MultisiteTopology + PostgreSQL> Interpret<T> for MultisitePostgreSQLInterpret {
+    fn get_name(&self) -> InterpretName {
+        InterpretName::Custom("MultisitePostgreSQLInterpret")
+    }
+
+    fn get_version(&self) -> Version {
+        self.version.clone()
+    }
+
+    fn get_status(&self) -> InterpretStatus {
+        self.status.clone()
+    }
+
+    fn get_children(&self) -> Vec<Id> {
+        todo!("Track child interprets per site")
+    }
+
+async fn execute(
+    &self,
+    inventory: &Inventory,
+    topology: &T,
+) -> Result<Outcome, InterpretError> {
+
+        info!(
+            "Orchestrating multisite PostgreSQL: primary {:?}, replicas {:?}",
+            self.score.primary_site, self.score.replica_sites
+        );
+
+        // 1. Deploy primary
+        let primary_topo = topology.primary();
+
+        let primary_config = PostgreSQLConfig {
+            cluster_name: self.score.cluster_name.clone(),
+            instances: self.score.instances,
+            storage_size: self.score.storage_size.clone(),
+            role: ClusterRole::Primary,
+        };
+        let primary_cluster_name = primary_topo
+            .deploy(&primary_config)
+            .await
+            .map_err(|e| InterpretError::from(format!("Primary deploy failed: {e}")))?;
+
+        // 2. Extract certs & public endpoint from primary
+        let certs = primary_topo
+            .get_replication_certs(&primary_cluster_name)
+            .await
+            .map_err(|e| InterpretError::from(format!("Certs extract failed: {e}")))?;
+        let public_endpoint = primary_topo
+            .get_public_endpoint(&primary_cluster_name)
+            .await??
+            .ok_or_else(|| InterpretError::from("No public endpoint on primary"))?;
+
+        // 3. Deploy replicas
+        for replica_site in &self.score.replica_sites {
+let replica_topo = topology.replica();
+
+                .map_err(|e| {
+                    InterpretError::from(format!(
+                        "Replica site {:?} lookup failed: {e}",
+                        replica_site
+                    ))
+                })?;
+
+            let connection_params: HashMap<String, String> = [
+                ("host".to_string(), public_endpoint.host.clone()),
+                ("port".to_string(), public_endpoint.port.to_string()),
+                ("dbname".to_string(), "postgres".to_string()),
+                ("user".to_string(), "streaming_replica".to_string()),
+                ("sslmode".to_string(), "verify-ca".to_string()),
+                ("sslnegotiation".to_string(), "direct".to_string()),
+            ]
+            .into_iter()
+            .collect();
+
+            let external_cluster = ExternalClusterConfig {
+                name: "primary-cluster".to_string(),
+                connection_parameters: connection_params,
+            };
+
+            let replica_config_struct = ReplicaConfig {
+                primary_cluster_name: primary_cluster_name.clone(),
+                replication_certs: certs.clone(),
+                bootstrap: BootstrapConfig {
+                    strategy: BootstrapStrategy::PgBasebackup,
+                },
+                external_cluster,
+            };
+
+            let replica_config = PostgreSQLConfig {
+                cluster_name: format!("{}-replica-{}", self.score.cluster_name, replica_site),
+                instances: self.score.instances,
+                storage_size: self.score.storage_size.clone(),
+                role: ClusterRole::Replica(replica_config_struct),
+            };
+
+            let _replica_cluster = replica_topo.deploy(&replica_config).await.map_err(|e| {
+                InterpretError::from(format!("Replica {:?} deploy failed: {e}", replica_site))
+            })?;
+        }
+
+        Ok(Outcome::success(format!(
+            "Multisite PostgreSQL `{}` deployed: primary `{}`, {} replicas",
+            self.score.cluster_name,
+            primary_cluster_name,
+            self.score.replica_sites.len()
+        )))
+    }
+}

harmony_types/src/lib.rs

@@ -1,3 +1,4 @@
 pub mod id;
 pub mod net;
 pub mod switch;
+pub mod storage;

harmony_types/src/storage.rs

@@ -0,0 +1,6 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Serialize, Deserialize, PartialOrd, Ord, Debug)]
+pub struct StorageSize {
+    size_bytes: u64,
+}