Implement Phase 1 of KAT (#1)
**Phase 1: State Management & Leader Election**
* **Goal**: A functional embedded etcd and leader election mechanism.
* **Tasks**:
1. Implement the `StateStore` interface (RFC 5.1) with an etcd backend (`internal/store/etcd.go`).
2. Integrate embedded etcd server into `kat-agent` (RFC 2.2, 5.2), configurable via `cluster.kat` parameters.
3. Implement leader election using `go.etcd.io/etcd/client/v3/concurrency` (RFC 5.3).
4. Basic `kat-agent init` functionality:
* Parse `cluster.kat`.
* Start single-node embedded etcd.
* Campaign for and become leader.
* Store initial cluster configuration (UID, CIDRs from `cluster.kat`) in etcd.
* **Milestone**:
* A single `kat-agent init --config cluster.kat` process starts, initializes etcd, and logs that it has become the leader.
* The cluster configuration from `cluster.kat` can be verified in etcd using an etcd client.
* `StateStore` interface methods (`Put`, `Get`, `Delete`, `List`) are testable against the embedded etcd.
Reviewed-on: #1
This commit is contained in:
395
internal/store/etcd_test.go
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395
internal/store/etcd_test.go
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package store
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import (
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"context"
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"fmt"
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"os"
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"sync"
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"testing"
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"time"
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"github.com/google/uuid"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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// TestEtcdStore tests the basic operations of the EtcdStore implementation
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// This is an integration test that requires starting an embedded etcd server
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func TestEtcdStore(t *testing.T) {
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// Create a temporary directory for etcd data
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tempDir, err := os.MkdirTemp("", "etcd-test-*")
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require.NoError(t, err)
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defer os.RemoveAll(tempDir)
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// Configure and start embedded etcd
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etcdConfig := EtcdEmbedConfig{
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Name: "test-node",
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DataDir: tempDir,
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ClientURLs: []string{"http://localhost:0"}, // Use port 0 to get a random available port
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PeerURLs: []string{"http://localhost:0"},
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}
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etcdServer, err := StartEmbeddedEtcd(etcdConfig)
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require.NoError(t, err)
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// Use a cleanup function instead of defer to avoid double-close
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var once sync.Once
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t.Cleanup(func() {
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once.Do(func() {
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if etcdServer != nil {
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// Wrap in a recover to handle potential "close of closed channel" panic
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func() {
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defer func() {
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if r := recover(); r != nil {
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// Log the panic but continue - the server was likely already closed
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t.Logf("Recovered from panic while closing etcd server: %v", r)
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}
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}()
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etcdServer.Close()
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}()
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}
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})
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})
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// Get the actual client URL that was assigned
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clientURL := etcdServer.Clients[0].Addr().String()
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// Create the store
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store, err := NewEtcdStore([]string{clientURL}, etcdServer)
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require.NoError(t, err)
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defer store.Close()
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// Test context with timeout
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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// Test Put and Get
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t.Run("PutAndGet", func(t *testing.T) {
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key := "/test/key1"
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value := []byte("test-value-1")
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err := store.Put(ctx, key, value)
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require.NoError(t, err)
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kv, err := store.Get(ctx, key)
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require.NoError(t, err)
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assert.Equal(t, key, kv.Key)
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assert.Equal(t, value, kv.Value)
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assert.Greater(t, kv.Version, int64(0))
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})
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// Test List
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t.Run("List", func(t *testing.T) {
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// Put multiple keys with same prefix
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prefix := "/test/list/"
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for i := 0; i < 3; i++ {
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key := fmt.Sprintf("%s%d", prefix, i)
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value := []byte(fmt.Sprintf("value-%d", i))
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err := store.Put(ctx, key, value)
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require.NoError(t, err)
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}
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// List keys with prefix
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kvs, err := store.List(ctx, prefix)
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require.NoError(t, err)
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assert.Len(t, kvs, 3)
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// Verify each key starts with prefix
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for _, kv := range kvs {
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assert.True(t, len(kv.Key) > len(prefix))
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assert.Equal(t, prefix, kv.Key[:len(prefix)])
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}
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})
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// Test Delete
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t.Run("Delete", func(t *testing.T) {
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key := "/test/delete-key"
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value := []byte("delete-me")
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// Put a key
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err := store.Put(ctx, key, value)
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require.NoError(t, err)
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// Verify it exists
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_, err = store.Get(ctx, key)
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require.NoError(t, err)
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// Delete it
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err = store.Delete(ctx, key)
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require.NoError(t, err)
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// Verify it's gone
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_, err = store.Get(ctx, key)
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require.Error(t, err)
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})
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// Test Watch
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t.Run("Watch", func(t *testing.T) {
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prefix := "/test/watch/"
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key := prefix + "key1"
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// Start watching before any changes
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watchCh, err := store.Watch(ctx, prefix, 0)
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require.NoError(t, err)
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// Make changes in a goroutine
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go func() {
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time.Sleep(100 * time.Millisecond)
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store.Put(ctx, key, []byte("watch-value-1"))
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time.Sleep(100 * time.Millisecond)
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store.Put(ctx, key, []byte("watch-value-2"))
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time.Sleep(100 * time.Millisecond)
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store.Delete(ctx, key)
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}()
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// Collect events
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var events []WatchEvent
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timeout := time.After(2 * time.Second)
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eventLoop:
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for {
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select {
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case event, ok := <-watchCh:
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if !ok {
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break eventLoop
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}
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events = append(events, event)
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if len(events) >= 3 {
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break eventLoop
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}
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case <-timeout:
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t.Fatal("Timed out waiting for watch events")
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break eventLoop
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}
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}
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// Verify events
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require.Len(t, events, 3)
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// First event: Put watch-value-1
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assert.Equal(t, EventTypePut, events[0].Type)
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assert.Equal(t, key, events[0].KV.Key)
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assert.Equal(t, []byte("watch-value-1"), events[0].KV.Value)
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// Second event: Put watch-value-2
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assert.Equal(t, EventTypePut, events[1].Type)
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assert.Equal(t, key, events[1].KV.Key)
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assert.Equal(t, []byte("watch-value-2"), events[1].KV.Value)
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// Third event: Delete
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assert.Equal(t, EventTypeDelete, events[2].Type)
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assert.Equal(t, key, events[2].KV.Key)
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})
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// Test DoTransaction
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t.Run("DoTransaction", func(t *testing.T) {
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key1 := "/test/txn/key1"
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key2 := "/test/txn/key2"
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// Put key1 first
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err := store.Put(ctx, key1, []byte("txn-value-1"))
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require.NoError(t, err)
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// Get key1 to get its version
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kv, err := store.Get(ctx, key1)
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require.NoError(t, err)
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version := kv.Version
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// Transaction: If key1 has expected version, put key2
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checks := []Compare{
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{Key: key1, ExpectedVersion: version},
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}
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onSuccess := []Op{
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{Type: OpPut, Key: key2, Value: []byte("txn-value-2")},
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}
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onFailure := []Op{} // Empty for this test
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committed, err := store.DoTransaction(ctx, checks, onSuccess, onFailure)
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require.NoError(t, err)
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assert.True(t, committed)
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// Verify key2 was created
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kv2, err := store.Get(ctx, key2)
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require.NoError(t, err)
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assert.Equal(t, []byte("txn-value-2"), kv2.Value)
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// Now try a transaction that should fail
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checks = []Compare{
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{Key: key1, ExpectedVersion: version + 100}, // Wrong version
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}
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committed, err = store.DoTransaction(ctx, checks, onSuccess, onFailure)
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require.NoError(t, err)
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assert.False(t, committed)
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})
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}
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// TestLeaderElection tests the Campaign, Resign, and GetLeader methods
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func TestLeaderElection(t *testing.T) {
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// Create a temporary directory for etcd data
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tempDir, err := os.MkdirTemp("", "etcd-election-test-*")
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require.NoError(t, err)
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defer os.RemoveAll(tempDir)
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// Configure and start embedded etcd
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etcdConfig := EtcdEmbedConfig{
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Name: "election-test-node",
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DataDir: tempDir,
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ClientURLs: []string{"http://localhost:0"},
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PeerURLs: []string{"http://localhost:0"},
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}
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etcdServer, err := StartEmbeddedEtcd(etcdConfig)
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require.NoError(t, err)
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// Use a cleanup function instead of defer to avoid double-close
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var once sync.Once
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t.Cleanup(func() {
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once.Do(func() {
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if etcdServer != nil {
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// Wrap in a recover to handle potential "close of closed channel" panic
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func() {
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defer func() {
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if r := recover(); r != nil {
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// Log the panic but continue - the server was likely already closed
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t.Logf("Recovered from panic while closing etcd server: %v", r)
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}
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}()
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etcdServer.Close()
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}()
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}
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})
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})
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// Get the actual client URL that was assigned
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clientURL := etcdServer.Clients[0].Addr().String()
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// Create the store
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store, err := NewEtcdStore([]string{clientURL}, etcdServer)
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require.NoError(t, err)
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defer store.Close()
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// Test context with timeout
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ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
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defer cancel()
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// Test Campaign and GetLeader
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t.Run("CampaignAndGetLeader", func(t *testing.T) {
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leaderID := "test-leader-" + uuid.New().String()[:8]
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// Campaign for leadership
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leadershipCtx, err := store.Campaign(ctx, leaderID, 5)
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require.NoError(t, err)
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require.NotNil(t, leadershipCtx)
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// Wait a moment for leadership to be established
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time.Sleep(100 * time.Millisecond)
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// Verify we are the leader
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currentLeader, err := store.GetLeader(ctx)
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require.NoError(t, err)
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assert.Equal(t, leaderID, currentLeader)
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// Resign leadership
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err = store.Resign(ctx)
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require.NoError(t, err)
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// Wait a moment for resignation to take effect
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time.Sleep(500 * time.Millisecond)
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// Verify leadership context is cancelled
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select {
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case <-leadershipCtx.Done():
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// Expected
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default:
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t.Fatal("Leadership context should be cancelled after resign")
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}
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// Verify no leader or different leader
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currentLeader, err = store.GetLeader(ctx)
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require.NoError(t, err)
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assert.NotEqual(t, leaderID, currentLeader, "Should not still be leader after resigning")
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})
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// Test multiple candidates
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t.Run("MultipleLeaderCandidates", func(t *testing.T) {
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// Create a second store client
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store2, err := NewEtcdStore([]string{clientURL}, nil) // No embedded server for this one
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require.NoError(t, err)
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defer store2.Close()
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leaderID1 := "leader1-" + uuid.New().String()[:8]
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leaderID2 := "leader2-" + uuid.New().String()[:8]
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// First store campaigns
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leadershipCtx1, err := store.Campaign(ctx, leaderID1, 5)
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require.NoError(t, err)
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// Wait a moment for leadership to be established
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time.Sleep(100 * time.Millisecond)
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// Verify first store is leader
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currentLeader, err := store.GetLeader(ctx)
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require.NoError(t, err)
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assert.Equal(t, leaderID1, currentLeader)
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// Second store campaigns but shouldn't become leader yet
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leadershipCtx2, err := store2.Campaign(ctx, leaderID2, 5)
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require.NoError(t, err)
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// Wait a moment to ensure leadership state is stable
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time.Sleep(100 * time.Millisecond)
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// Verify first store is still leader
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currentLeader, err = store.GetLeader(ctx)
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require.NoError(t, err)
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assert.Equal(t, leaderID1, currentLeader)
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// First store resigns
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err = store.Resign(ctx)
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require.NoError(t, err)
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// Wait for second store to become leader
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deadline := time.Now().Add(3 * time.Second)
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var leaderFound bool
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for time.Now().Before(deadline) {
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currentLeader, err = store2.GetLeader(ctx)
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if err == nil && currentLeader == leaderID2 {
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leaderFound = true
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break
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}
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time.Sleep(100 * time.Millisecond)
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}
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// Verify second store is now leader
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assert.True(t, leaderFound, "Second candidate should have become leader")
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assert.Equal(t, leaderID2, currentLeader)
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// Verify first leadership context is cancelled
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select {
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case <-leadershipCtx1.Done():
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// Expected
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default:
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t.Fatal("First leadership context should be cancelled after resign")
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}
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// Second store resigns
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err = store2.Resign(ctx)
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require.NoError(t, err)
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// Verify second leadership context is cancelled
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select {
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case <-leadershipCtx2.Done():
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// Expected
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default:
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t.Fatal("Second leadership context should be cancelled after resign")
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}
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})
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}
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// TestEtcdStoreWithMockEmbeddedEtcd tests the EtcdStore with a mock embedded etcd
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// This is a unit test that doesn't require starting a real etcd server
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func TestEtcdStoreWithMockEmbeddedEtcd(t *testing.T) {
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// This test would use mocks to test the EtcdStore without starting a real etcd server
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// For brevity, we'll skip the implementation of this test
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t.Skip("Mock-based unit test not implemented")
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}
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Reference in New Issue
Block a user