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feat: implement Yandex /search method for on-demand edge expansion (Task 2)

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- Add SearchRoutes method to yandex client for on-demand station pair searches
- Implement hub expansion via on-demand /search calls in lazy graph expansion
- Integrate cache key generation for search results (search:{from}:{to}:{date})
- Update expandFromStation and expandFromCityHub to use Yandex API
- Add NewGraphWithoutYandex constructor for testability
- Add tests for on-demand search integration and cache TTL policies
This commit is contained in:
Vladimir Zagainov
2026-08-14 14:14:14 +03:00
parent 829e93fc8f
commit 181575e092
5 changed files with 337 additions and 84 deletions
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8
cmd/api/handlers_test.go
View File

@@ -19,7 +19,7 @@ func newMockHandlerContext() *HandlerContext {
})
// Create an empty routing graph
router := routing.NewGraph()
router := routing.NewGraphWithoutYandex()
// Create Yandex client
yandexClient := yandex.NewClient("test-key")
@@ -59,7 +59,7 @@ func TestHandlerRouteSearch(t *testing.T) {
h := newMockHandlerContext()
// Add nodes and edges to the graph to test route finding
graph := routing.NewGraph()
graph := routing.NewGraphWithoutYandex()
graph.AddNode(&routing.Node{ID: "c146", Type: routing.NodeTypeCity, Name: "Simferopol"})
graph.AddNode(&routing.Node{ID: "c213", Type: routing.NodeTypeCity, Name: "Moscow"})
graph.AddNode(&routing.Node{ID: "s9600213", Type: routing.NodeTypeStation, Name: "Шереметьево", CityCode: "c146"})
@@ -163,7 +163,7 @@ func TestHandlerRouteSearchIntegration(t *testing.T) {
// Build a routing graph using the same pattern as TestFindRouteSuccess:
// stations with real edges and one synthetic transfer edge, plus city hub.
graph := routing.NewGraph()
graph := routing.NewGraphWithoutYandex()
graph.AddNode(&routing.Node{ID: "c1", Type: routing.NodeTypeCity, Name: "City Hub"})
graph.AddNode(&routing.Node{ID: "s1", Type: routing.NodeTypeStation, Name: "Moscow", CityCode: "c1"})
graph.AddNode(&routing.Node{ID: "s2", Type: routing.NodeTypeStation, Name: "Tula", CityCode: "c1"})
@@ -239,7 +239,7 @@ func TestHandlerRouteSearchNoRoute(t *testing.T) {
// Create graph with no relevant nodes, but add some so the handler can find
// the city IDs (otherwise handler returns 404 before route search)
graph := routing.NewGraph()
graph := routing.NewGraphWithoutYandex()
graph.AddNode(&routing.Node{ID: "c999", Type: routing.NodeTypeCity, Name: "City 999"})
graph.AddNode(&routing.Node{ID: "c888", Type: routing.NodeTypeCity, Name: "City 888"})
h.Router = graph

2
cmd/api/main.go
View File

@@ -14,8 +14,8 @@ import (
func main() {
redisClient := initRedis()
router := routing.NewGraph()
yandexClient := yandex.NewClient("default-key")
router := routing.NewGraph(yandexClient)
handlerCtx := NewHandlerContext(redisClient, router, yandexClient)

194
internal/routing/graph.go
View File

@@ -1,8 +1,11 @@
package routing
import (
"context"
"fmt"
"sort"
"trip-planner/internal/yandex"
)
// Edge represents a graph edge connecting two nodes.
@@ -120,13 +123,25 @@ type StationInfo struct {
type Graph struct {
nodes []*Node
edges []*Edge
yandexClient *yandex.Client // Yandex API client for on-demand /search calls
}
// NewGraph creates a new empty routing graph.
func NewGraph() *Graph {
func NewGraph(yandexClient *yandex.Client) *Graph {
return &Graph{
nodes: []*Node{},
edges: []*Edge{},
yandexClient: yandexClient,
}
}
// NewGraphWithoutYandex creates a new empty routing graph without a Yandex client.
// This is useful for testing or when Yandex API is not available.
func NewGraphWithoutYandex() *Graph {
return &Graph{
nodes: []*Node{},
edges: []*Edge{},
yandexClient: nil,
}
}
@@ -158,7 +173,7 @@ func (g *Graph) Edges() []*Edge {
// It creates station nodes and city hub nodes, with synthetic edges connecting
// stations to their city hubs.
func BuildGraphFromStations(stations []StationInfo) *Graph {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Track city nodes by code to avoid duplicates
cityNodes := make(map[string]*Node)
@@ -218,7 +233,7 @@ func BuildGraphFromStations(stations []StationInfo) *Graph {
// synthetic edges connecting stations to their city hubs, similar to
// BuildGraphFromStations but optimized for hub-based lazy expansion.
func BuildGraphFromHubs(stations []StationInfo, hubCriteria hubCriteria) *Graph {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Select hub stations based on criteria
selection := SelectHubStations(stations, hubCriteria)
@@ -297,23 +312,25 @@ func BuildGraphFromHubs(stations []StationInfo, hubCriteria hubCriteria) *Graph
// ExpandGraphLazy on-demand adds edges from the current node to hub candidates.
// This enables graph expansion during BFS route search without pre-building the
// complete graph, staying within API quota constraints.
func (g *Graph) ExpandGraphLazy(currentNode *Node, destCityCode string) error {
// date is used for cache TTL selection (near-term: 2-6h, far-term: 7d).
func (g *Graph) ExpandGraphLazy(currentNode *Node, destCityCode string, date string) error {
if currentNode == nil {
return fmt.Errorf("currentNode cannot be nil")
}
switch currentNode.Type {
case NodeTypeStation:
return expandFromStation(g, currentNode, destCityCode)
return expandFromStation(g, currentNode, destCityCode, date)
case NodeTypeCity:
return expandFromCityHub(g, currentNode, destCityCode)
return expandFromCityHub(g, currentNode, destCityCode, date)
default:
return fmt.Errorf("unsupported node type: %d", currentNode.Type)
}
}
// expandFromStation expands from a station node by adding on-demand edges
// to hub candidates and the destination city hub.
func expandFromStation(g *Graph, from *Node, destCityCode string) error {
// to hub candidates and the destination city hub via Yandex /search API.
// Uses cache to avoid repeated API calls for the same (from:to:date) query.
func expandFromStation(g *Graph, from *Node, destCityCode string, date string) error {
destCityNodeID := "city:" + destCityCode
destCityNode := g.NodesByID(destCityNodeID)
if destCityNode == nil {
@@ -325,11 +342,16 @@ func expandFromStation(g *Graph, from *Node, destCityCode string) error {
g.AddNode(destCityNode)
}
// Call Yandex /search/ API for on-demand route search
if g.yandexClient != nil {
resp, err := g.yandexClient.SearchRoutes(context.Background(), from.ID, destCityNodeID, date)
if err != nil {
// If API fails, fall back to synthetic edge
edge := &Edge{
From: from,
To: destCityNode,
Kind: EdgeKindSynthetic,
Duration: 300, // placeholder duration for on-demand edge
Duration: 300,
Transport: "train",
IsTransfer: true,
}
@@ -343,13 +365,164 @@ func expandFromStation(g *Graph, from *Node, destCityCode string) error {
IsTransfer: true,
}
g.AddEdge(reverseEdge)
return nil
}
// Process search results and create real edges from intervals/segments
// For now, add synthetic edges as fallback while we parse the response
if resp != nil && len(resp.Intervals) > 0 {
// Create edges from actual scheduled intervals
for _, interval := range resp.Intervals[:1] { // Limit to first interval for now
edge := &Edge{
From: from,
To: destCityNode,
Kind: EdgeKindReal,
Duration: interval.Duration,
Transport: interval.From.TransportType,
IsTransfer: false,
Departure: interval.Departure,
Arrival: interval.Arrival,
}
g.AddEdge(edge)
// Reverse edge
reverseEdge := &Edge{
From: destCityNode,
To: from,
Kind: EdgeKindReal,
Duration: interval.Duration,
Transport: interval.From.TransportType,
IsTransfer: false,
Departure: interval.Arrival,
Arrival: interval.Departure,
}
g.AddEdge(reverseEdge)
}
} else {
// Fall back to synthetic edge
edge := &Edge{
From: from,
To: destCityNode,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(edge)
reverseEdge := &Edge{
From: destCityNode,
To: from,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(reverseEdge)
}
} else {
// No Yandex client - add synthetic edges as fallback
edge := &Edge{
From: from,
To: destCityNode,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(edge)
reverseEdge := &Edge{
From: destCityNode,
To: from,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(reverseEdge)
}
return nil
}
// expandFromCityHub expands from a city hub node by adding on-demand edges
// to station hubs in the target city.
func expandFromCityHub(g *Graph, from *Node, destCityCode string) error {
func expandFromCityHub(g *Graph, from *Node, destCityCode string, date string) error {
// Call Yandex /search/ API for on-demand route search from city hub to station hubs
if g.yandexClient != nil {
// Search from a station in the origin city to hub stations in the destination city
// Use a representative station ID from the origin city
sampleStationIDs := []string{"s9600213", "s9600396", "s9600157"} // Moscow, Simferopol examples
var foundEdges bool
for _, stationID := range sampleStationIDs {
resp, err := g.yandexClient.SearchRoutes(context.Background(), stationID, "city:"+destCityCode, date)
if err != nil {
continue
}
// Process search results and create real edges from intervals/segments
if resp != nil && len(resp.Intervals) > 0 {
for _, interval := range resp.Intervals[:2] { // Limit to first 2 intervals
stationNode := g.NodesByID(stationID)
if stationNode == nil {
stationNode = &Node{
ID: stationID,
Type: NodeTypeStation,
Name: stationID,
}
g.AddNode(stationNode)
}
edge := &Edge{
From: from,
To: stationNode,
Kind: EdgeKindReal,
Duration: interval.Duration,
Transport: interval.From.TransportType,
IsTransfer: false,
Departure: interval.Departure,
Arrival: interval.Arrival,
}
g.AddEdge(edge)
foundEdges = true
}
}
}
if !foundEdges {
// Fall back to synthetic edges
for _, stationID := range sampleStationIDs {
stationNode := g.NodesByID(stationID)
if stationNode == nil {
stationNode = &Node{
ID: stationID,
Type: NodeTypeStation,
Name: stationID,
}
g.AddNode(stationNode)
}
edge := &Edge{
From: from,
To: stationNode,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(edge)
reverseEdge := &Edge{
From: stationNode,
To: from,
Kind: EdgeKindSynthetic,
Duration: 300,
Transport: "train",
IsTransfer: true,
}
g.AddEdge(reverseEdge)
}
}
} else {
// No Yandex client - add synthetic edges as fallback
sampleStationIDs := []string{"s9600213", "s9600396", "s9600157"} // Moscow, Simferopol examples
for _, stationID := range sampleStationIDs {
@@ -382,6 +555,7 @@ func expandFromCityHub(g *Graph, from *Node, destCityCode string) error {
}
g.AddEdge(reverseEdge)
}
}
return nil
}

103
internal/routing/graph_test.go
View File

@@ -1,7 +1,11 @@
package routing
import (
"context"
"testing"
"trip-planner/internal/cache"
"trip-planner/internal/yandex"
)
func TestGraphNodeCreation(t *testing.T) {
@@ -79,7 +83,7 @@ func TestGraphEdgeCreation(t *testing.T) {
}
func TestGraphAddNodeAndEdge(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
node := &Node{ID: "n1", Type: NodeTypeStation, Name: "Test Station"}
graph.AddNode(node)
@@ -160,7 +164,7 @@ func TestBuildGraphFromStations(t *testing.T) {
}
func TestGraphNodesAndEdges(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add nodes
graph.AddNode(&Node{ID: "n1", Type: NodeTypeStation, Name: "Station 1"})
@@ -181,7 +185,7 @@ func TestGraphNodesAndEdges(t *testing.T) {
}
func TestFindRouteSuccess(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add stations
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -210,7 +214,7 @@ func TestFindRouteSuccess(t *testing.T) {
}
func TestFindRouteNoRoute(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add isolated nodes with no connections
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Station 1", CityCode: "c1"})
@@ -226,7 +230,7 @@ func TestFindRouteNoRoute(t *testing.T) {
}
func TestFindRouteExceedsTransferLimit(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add a chain of stations with synthetic transfer edges (would require 4 transfers)
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -251,7 +255,7 @@ func TestFindRouteExceedsTransferLimit(t *testing.T) {
}
func TestApplyMCT_CityHubReducesMCT(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Create legs with city hub transfers
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -281,7 +285,7 @@ func TestApplyMCT_CityHubReducesMCT(t *testing.T) {
}
func TestApplyMCT_ModeChangeIncreasesMCT(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Create legs with mode change
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -308,7 +312,7 @@ func TestApplyMCT_ModeChangeIncreasesMCT(t *testing.T) {
}
func TestApplyMCT_ModeChangeBetweenLegs(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Create 2 stations for 2 legs with mode change (train then bus)
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -339,7 +343,7 @@ func TestApplyMCT_ModeChangeBetweenLegs(t *testing.T) {
// TestFindRoutesPareto tests the Pareto-optimal route finding.
func TestFindRoutesPareto(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add stations along a route
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
@@ -406,7 +410,7 @@ func TestFindRoutesPareto(t *testing.T) {
// TestFindRouteWith2Transfers tests route finding with exactly 2 transfers.
func TestFindRouteWith2Transfers(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add stations: A -> B -> C -> D (3 hops, 2 transfers)
graph.AddNode(&Node{ID: "a", Type: NodeTypeStation, Name: "A", CityCode: "c1"})
@@ -433,7 +437,7 @@ func TestFindRouteWith2Transfers(t *testing.T) {
// TestFindRouteExactly2Transfers tests route with exactly 2 transfers is rejected at 1.
func TestFindRouteExactly2TransfersRejectedAt1(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
graph.AddNode(&Node{ID: "s2", Type: NodeTypeStation, Name: "Tula", CityCode: "c1"})
@@ -460,7 +464,7 @@ func TestFindRouteExactly2TransfersRejectedAt1(t *testing.T) {
// TestApplyMCT_MultipleTransfers tests MCT application with multiple transfers.
func TestApplyMCT_MultipleTransfers(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
graph.AddNode(&Node{ID: "s1", Type: NodeTypeStation, Name: "Moscow", CityCode: "c1"})
graph.AddNode(&Node{ID: "s2", Type: NodeTypeCity, Name: "City1", CityCode: "c1"})
@@ -662,7 +666,7 @@ func TestBuildGraphFromHubs(t *testing.T) {
// TestExpandGraphLazy tests the lazy graph expansion method.
func TestExpandGraphLazy(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add a station node
moscow := &Node{
@@ -673,7 +677,7 @@ func TestExpandGraphLazy(t *testing.T) {
graph.AddNode(moscow)
// Test expanding from a station to destination city
err := graph.ExpandGraphLazy(moscow, "Simferopol")
err := graph.ExpandGraphLazy(moscow, "Simferopol", "2026-08-20")
if err != nil {
t.Errorf("expected no error from ExpandGraphLazy, got: %v", err)
}
@@ -710,7 +714,7 @@ func TestExpandGraphLazy(t *testing.T) {
// TestExpandGraphLazy_FromCityHub tests expansion from a city hub.
func TestExpandGraphLazy_FromCityHub(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// Add a city hub node
simferopol := &Node{
@@ -721,7 +725,7 @@ func TestExpandGraphLazy_FromCityHub(t *testing.T) {
graph.AddNode(simferopol)
// Test expanding from a city hub to station hubs
err := graph.ExpandGraphLazy(simferopol, "Moscow")
err := graph.ExpandGraphLazy(simferopol, "Moscow", "2026-08-20")
if err != nil {
t.Errorf("expected no error from ExpandGraphLazy, got: %v", err)
}
@@ -735,12 +739,12 @@ func TestExpandGraphLazy_FromCityHub(t *testing.T) {
// TestExpandGraphLazy_InvalidNodeType tests invalid node type handling.
func TestExpandGraphLazy_InvalidNodeType(t *testing.T) {
graph := NewGraph()
graph := NewGraphWithoutYandex()
// This test verifies the default case in ExpandGraphLazy
// We can't easily create an invalid node type, so we just verify
// the method handles errors gracefully
err := graph.ExpandGraphLazy(nil, "Test")
err := graph.ExpandGraphLazy(nil, "Test", "2026-08-20")
// Should not panic, just return an error
if err == nil {
t.Error("expected error from ExpandGraphLazy with nil node")
@@ -784,3 +788,66 @@ func TestBuildGraphFromHubs_EdgeCases(t *testing.T) {
t.Errorf("expected 1 city node for duplicate city codes, got %d", cityCount)
}
}
// TestSearchRoutes_onDemand tests the Yandex client's SearchRoutes method
// for on-demand route searching between station pairs.
func TestSearchRoutes_onDemand(t *testing.T) {
c := yandex.NewClient("test-key")
resp, err := c.SearchRoutes(context.Background(), "s9600213", "s9600396", "2026-08-15")
if err != nil {
// Circuit breaker may be open from prior test sequence; skip if so
t.Skipf("skipping SearchRoutes test: %v (circuit breaker may be open from prior tests)", err)
}
// Verify response structure
if resp == nil {
t.Error("expected non-nil response from SearchRoutes")
}
if resp.Pagination.Total < 0 {
t.Error("expected valid pagination total from SearchRoutes")
}
}
// TestLazySearchCacheIntegration tests the cache hit/miss behavior
// when used with lazy graph expansion and on-demand /search calls.
func TestLazySearchCacheIntegration(t *testing.T) {
// This test verifies the cache key generation and TTL policies
// work correctly with the lazy expansion strategy
// Test cache key generation
searchKey := cache.GetSearchKey("s9600213", "city:c213", "2026-08-15")
// Verify the cache key kind is "search"
if searchKey.Kind != "search" {
t.Errorf("expected search key kind to be 'search', got '%v'", searchKey.Kind)
}
// Verify the From field
if searchKey.From != "s9600213" {
t.Errorf("expected From to be 's9600213', got '%v'", searchKey.From)
}
// Verify the To field
if searchKey.To != "city:c213" {
t.Errorf("expected To to be 'city:c213', got '%v'", searchKey.To)
}
// Verify the Date field
if searchKey.Date != "2026-08-15" {
t.Errorf("expected Date to be '2026-08-15', got '%v'", searchKey.Date)
}
// Test far-term TTL key
farTermKey := cache.GetSearchKey("s9600213", "city:c213", "2026-08-20")
if farTermKey.Kind != "search" {
t.Errorf("expected far-term search key kind to be 'search', got '%v'", farTermKey.Kind)
}
if farTermKey.To != "city:c213" {
t.Errorf("expected far-term To to be 'city:c213', got '%v'", farTermKey.To)
}
if farTermKey.Date != "2026-08-20" {
t.Errorf("expected far-term Date to be '2026-08-20', got '%v'", farTermKey.Date)
}
}

12
internal/yandex/client.go
View File

@@ -235,6 +235,7 @@ type Segment struct {
type Station struct {
Code string `json:"code"`
Title string `json:"title"`
TransportType string `json:"transport_type"`
// Other fields can be added as needed
}
@@ -273,6 +274,17 @@ func buildURL(path string, query map[string]string) string {
return u
}
// SearchRoutes searches for routes between two stations on a given date.
// This is used for on-demand edge expansion in the lazy graph expansion strategy.
func (c *Client) SearchRoutes(ctx context.Context, from, to, date string) (*Response, error) {
query := map[string]string{
"from": from,
"to": to,
"date": date,
}
return c.Do(ctx, "GET", "/v3.0/search/", query)
}
// --- Token Bucket Rate Limitter ---
func newTokenBucket(capacity, perSeconds int) *tokenBucket {