Configuration: allow custom health check endpoint

resolves apollographql#2938 Adds a configuration option for custom health check endpoints, using `/health` as default
aaronArinder · Nov 6, 2023 · 4ff6c68 · 4ff6c68
1 parent 65f97e1
commit 4ff6c68
Show file tree

Hide file tree

Showing 7 changed files with 108 additions and 11 deletions.
diff --git a/.changesets/config_aaron_allow_custom_healthcheck_endpoint.md b/.changesets/config_aaron_allow_custom_healthcheck_endpoint.md
@@ -0,0 +1,9 @@
+### Configuration: allow custom health check endpoint ([Issue #2938](https://github.com/apollographql/router/issues/2938))
+
+Adds a configuration option for custom health check endpoints, using `/health` as default
+
+
+<!-- start metadata -->
+---
+
+By [@aaronArinder](https://github.com/aaronArinder) in https://github.com/apollographql/router/pull/4145
diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
@@ -76,6 +76,9 @@ The CI checks require `cargo-deny` and `cargo-about` which can both be installed
 - `cargo install cargo-deny`
 - `cargo install cargo-about`
 
+Updating the snapshots used during testing requires installing `cargo-insta`:
+- `cargo install cargo-insta`
+
 They also need you to have the federation-demo project up and running,
 as explained in the Getting started section above.
 

diff --git a/apollo-router/src/axum_factory/axum_http_server_factory.rs b/apollo-router/src/axum_factory/axum_http_server_factory.rs
@@ -103,13 +103,14 @@ where
 
     if configuration.health_check.enabled {
         tracing::info!(
-            "Health check endpoint exposed at {}/health",
-            configuration.health_check.listen
+            "Health check exposed at {}/{}",
+            configuration.health_check.listen,
+            configuration.health_check.path
         );
         endpoints.insert(
             configuration.health_check.listen.clone(),
             Endpoint::from_router_service(
-                "/health".to_string(),
+                configuration.health_check.path.clone(),
                 service_fn(move |req: router::Request| {
                     let mut status_code = StatusCode::OK;
                     let health = if let Some(query) = req.router_request.uri().query() {

diff --git a/apollo-router/src/configuration/mod.rs b/apollo-router/src/configuration/mod.rs
@@ -1161,25 +1161,43 @@ pub(crate) struct HealthCheck {
     /// Defaults to 127.0.0.1:8088
     pub(crate) listen: ListenAddr,
 
-    /// Set to false to disable the health check endpoint
+    /// Set to false to disable the health check
     pub(crate) enabled: bool,
+
+    /// Optionally set a custom healthcheck path
+    /// Defaults to /health
+    pub(crate) path: String,
 }
 
 fn default_health_check_listen() -> ListenAddr {
     SocketAddr::from_str("127.0.0.1:8088").unwrap().into()
 }
 
-fn default_health_check() -> bool {
+fn default_health_check_enabled() -> bool {
     true
 }
 
+fn default_health_check_path() -> String {
+    "/health".to_string()
+}
+
 #[buildstructor::buildstructor]
 impl HealthCheck {
     #[builder]
-    pub(crate) fn new(listen: Option<ListenAddr>, enabled: Option<bool>) -> Self {
+    pub(crate) fn new(
+        listen: Option<ListenAddr>,
+        enabled: Option<bool>,
+        path: Option<String>,
+    ) -> Self {
+        let mut path = path.unwrap_or_else(default_health_check_path);
+        if !path.starts_with('/') {
+            path = format!("/{path}").to_string();
+        }
+
         Self {
             listen: listen.unwrap_or_else(default_health_check_listen),
-            enabled: enabled.unwrap_or_else(default_health_check),
+            enabled: enabled.unwrap_or_else(default_health_check_enabled),
+            path,
         }
     }
 }
@@ -1188,10 +1206,20 @@ impl HealthCheck {
 #[buildstructor::buildstructor]
 impl HealthCheck {
     #[builder]
-    pub(crate) fn fake_new(listen: Option<ListenAddr>, enabled: Option<bool>) -> Self {
+    pub(crate) fn fake_new(
+        listen: Option<ListenAddr>,
+        enabled: Option<bool>,
+        path: Option<String>,
+    ) -> Self {
+        let mut path = path.unwrap_or_else(default_health_check_path);
+        if !path.starts_with('/') {
+            path = format!("/{path}").to_string();
+        }
+
         Self {
             listen: listen.unwrap_or_else(test_listen),
-            enabled: enabled.unwrap_or_else(default_health_check),
+            enabled: enabled.unwrap_or_else(default_health_check_enabled),
+            path,
         }
     }
 }

diff --git a/...r/src/configuration/snapshots/apollo_router__configuration__tests__schema_generation.snap b/...r/src/configuration/snapshots/apollo_router__configuration__tests__schema_generation.snap
@@ -1557,12 +1557,13 @@ expression: "&schema"
       "description": "Health check configuration",
       "default": {
         "listen": "127.0.0.1:8088",
-        "enabled": true
+        "enabled": true,
+        "path": "/health"
       },
       "type": "object",
       "properties": {
         "enabled": {
-          "description": "Set to false to disable the health check endpoint",
+          "description": "Set to false to disable the health check",
           "default": true,
           "type": "boolean"
         },
@@ -1579,6 +1580,11 @@ expression: "&schema"
               "type": "string"
             }
           ]
+        },
+        "path": {
+          "description": "Optionally set a custom healthcheck path Defaults to /health",
+          "default": "/health",
+          "type": "string"
         }
       },
       "additionalProperties": false

diff --git a/apollo-router/src/configuration/tests.rs b/apollo-router/src/configuration/tests.rs
@@ -934,6 +934,39 @@ fn test_deserialize_derive_default() {
     }
 }
 
+#[test]
+fn it_defaults_health_check_configuration() {
+    let conf = Configuration::default();
+    let addr: ListenAddr = SocketAddr::from_str("127.0.0.1:8088").unwrap().into();
+
+    assert_eq!(conf.health_check.listen, addr);
+    assert_eq!(&conf.health_check.path, "/health");
+
+    // Defaults to enabled: true
+    assert!(conf.health_check.enabled);
+}
+
+#[test]
+fn it_sets_custom_health_check_path() {
+    let conf = Configuration::builder()
+        .health_check(HealthCheck::new(None, None, Some("/healthz".to_string())))
+        .build()
+        .unwrap();
+
+    assert_eq!(&conf.health_check.path, "/healthz");
+}
+
+#[test]
+fn it_adds_slash_to_custom_health_check_path_if_missing() {
+    let conf = Configuration::builder()
+        // NB the missing `/`
+        .health_check(HealthCheck::new(None, None, Some("healthz".to_string())))
+        .build()
+        .unwrap();
+
+    assert_eq!(&conf.health_check.path, "/healthz");
+}
+
 fn has_field_level_serde_defaults(lines: &[&str], line_number: usize) -> bool {
     let serde_field_default = Regex::new(
         r#"^\s*#[\s\n]*\[serde\s*\((.*,)?\s*default\s*=\s*"[a-zA-Z0-9_:]+"\s*(,.*)?\)\s*\]\s*$"#,

diff --git a/docs/source/configuration/health-checks.mdx b/docs/source/configuration/health-checks.mdx
@@ -11,6 +11,23 @@ You can change this by setting `health_check`:
 health_check:
   listen: 127.0.0.1:8088
   enabled: true
+  path: /health
+```
+
+Each option is configurable. For example, we might want to set our health check to `127.0.0.1:8090/healthz`:
+
+```yaml title="router.yaml"
+health_check:
+  listen: 127.0.0.1:8090
+  enabled: true
+  path: /healthz
+```
+
+We can also disable the health check:
+
+```yaml title="router.yaml"
+health_check:
+  enabled: false
 ```
 
 ## Testing with `curl`