feat(wfe-core): add ServiceDefinition types and ServiceProvider trait

wfe-core/src/traits/mod.rs

@@ -1,5 +1,6 @@
 pub mod lifecycle;
 pub mod lock;
+pub mod service;
 pub mod log_sink;
 pub mod middleware;
 pub mod persistence;
@@ -19,4 +20,5 @@ pub use persistence::{
 pub use queue::QueueProvider;
 pub use registry::WorkflowRegistry;
 pub use search::{Page, SearchFilter, SearchIndex, WorkflowSearchResult};
+pub use service::ServiceProvider;
 pub use step::{HostContext, StepBody, StepExecutionContext, WorkflowData};

wfe-core/src/traits/service.rs

@@ -0,0 +1,31 @@
+use async_trait::async_trait;
+
+use crate::models::service::{ServiceDefinition, ServiceEndpoint};
+
+/// Provides infrastructure services (databases, caches, etc.) for workflows.
+///
+/// Implementations handle provisioning, readiness checking, and teardown
+/// of services on a specific platform (Kubernetes, containerd, etc.).
+#[async_trait]
+pub trait ServiceProvider: Send + Sync {
+    /// Check if this provider can provision the given services.
+    ///
+    /// Returns false if any service cannot be handled by this provider.
+    fn can_provision(&self, services: &[ServiceDefinition]) -> bool;
+
+    /// Provision all services for a workflow.
+    ///
+    /// Creates the service containers/pods, waits for them to be ready,
+    /// and returns endpoint information for each service.
+    async fn provision(
+        &self,
+        workflow_id: &str,
+        services: &[ServiceDefinition],
+    ) -> crate::Result<Vec<ServiceEndpoint>>;
+
+    /// Tear down all services for a workflow.
+    ///
+    /// Called on workflow completion, failure, or termination.
+    /// Should be idempotent -- safe to call multiple times.
+    async fn teardown(&self, workflow_id: &str) -> crate::Result<()>;
+}