Implement a /self/v1/health simple healthcheck endpoint

docs/api.md

@@ -26,6 +26,25 @@ endpoints.
 
 ## General
 
+### Health
+
+*This endpoint can be used as a health check for infrastructure integration
+such as Docker
+[`HEALTHCHECK`](https://docs.docker.com/reference/dockerfile/#healthcheck) or
+load balancer probes.*
+
+```
+GET /self/v1/health
+```
+
+=== "200"
+
+    Empty response body.
+
+=== "405"
+
+    The HTTP method is not `GET` or `HEAD`.
+
 ### List
 
 *This endpoint lists the contents of a directory at the specified `{path}`

src/index/index.cc

@@ -540,6 +540,7 @@ static auto index_main(const std::string_view &program,
              sourcemeta::one::HANDLER_SELF_V1_API_SCHEMAS_TRACE);
   router.add("/self/v1/api/schemas/search",
              sourcemeta::one::HANDLER_SELF_V1_API_SCHEMAS_SEARCH);
+  router.add("/self/v1/health", sourcemeta::one::HANDLER_SELF_V1_HEALTH);
   router.add("/self/v1/api/{+any}",
              sourcemeta::one::HANDLER_SELF_V1_API_DEFAULT);
 

src/server/server.cc

@@ -168,6 +168,23 @@ static auto handle_self_api_not_found(const std::filesystem::path &,
              "There is nothing at this URL");
 }
 
+static auto handle_self_v1_health(const std::filesystem::path &,
+                                  const std::span<std::string_view>,
+                                  sourcemeta::one::HTTPRequest &request,
+                                  sourcemeta::one::HTTPResponse &response)
+    -> void {
+  if (request.method() != "get" && request.method() != "head") {
+    json_error(request, response, sourcemeta::one::STATUS_METHOD_NOT_ALLOWED,
+               "method-not-allowed",
+               "This HTTP method is invalid for this URL");
+    return;
+  }
+
+  response.write_status(sourcemeta::one::STATUS_OK);
+  response.write_header("Access-Control-Allow-Origin", "*");
+  send_response(sourcemeta::one::STATUS_OK, request, response);
+}
+
 static auto handle_self_static(const std::filesystem::path &,
                                const std::span<std::string_view> matches,
                                sourcemeta::one::HTTPRequest &request,
@@ -261,7 +278,8 @@ static const Handler HANDLERS[] = {handle_default,
                                    handle_self_v1_api_schemas_trace,
                                    handle_self_v1_api_schemas_search,
                                    handle_self_api_not_found,
-                                   handle_self_static};
+                                   handle_self_static,
+                                   handle_self_v1_health};
 
 static auto dispatch(const sourcemeta::core::URITemplateRouterView &router,
                      const std::filesystem::path &base,

src/shared/include/sourcemeta/one/shared.h

@@ -24,6 +24,7 @@ constexpr auto HANDLER_SELF_V1_API_SCHEMAS_TRACE = 11;
 constexpr auto HANDLER_SELF_V1_API_SCHEMAS_SEARCH = 12;
 constexpr auto HANDLER_SELF_V1_API_DEFAULT = 13;
 constexpr auto HANDLER_SELF_STATIC = 14;
+constexpr auto HANDLER_SELF_V1_HEALTH = 15;
 
 } // namespace sourcemeta::one
 

test/e2e/populated/api/common/health.hurl

@@ -0,0 +1,52 @@
+GET {{base}}/self/v1/health
+HTTP 200
+Access-Control-Allow-Origin: *
+[Asserts]
+body == ""
+header "Link" not exists
+
+HEAD {{base}}/self/v1/health
+HTTP 200
+Access-Control-Allow-Origin: *
+[Asserts]
+header "Link" not exists
+
+POST {{base}}/self/v1/health
+HTTP 405
+Content-Type: application/problem+json
+Access-Control-Allow-Origin: *
+[Asserts]
+jsonpath "$.status" == 405
+jsonpath "$.title" == "sourcemeta:one/method-not-allowed"
+
+PUT {{base}}/self/v1/health
+HTTP 405
+Content-Type: application/problem+json
+Access-Control-Allow-Origin: *
+[Asserts]
+jsonpath "$.status" == 405
+jsonpath "$.title" == "sourcemeta:one/method-not-allowed"
+
+DELETE {{base}}/self/v1/health
+HTTP 405
+Content-Type: application/problem+json
+Access-Control-Allow-Origin: *
+[Asserts]
+jsonpath "$.status" == 405
+jsonpath "$.title" == "sourcemeta:one/method-not-allowed"
+
+PATCH {{base}}/self/v1/health
+HTTP 405
+Content-Type: application/problem+json
+Access-Control-Allow-Origin: *
+[Asserts]
+jsonpath "$.status" == 405
+jsonpath "$.title" == "sourcemeta:one/method-not-allowed"
+
+OPTIONS {{base}}/self/v1/health
+HTTP 405
+Content-Type: application/problem+json
+Access-Control-Allow-Origin: *
+[Asserts]
+jsonpath "$.status" == 405
+jsonpath "$.title" == "sourcemeta:one/method-not-allowed"