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Merge pull request #88 from krancour/add-redis-adapter
feat(storage): Add redis storage adapter
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,83 @@ | ||
| package redis | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "log" | ||
|
|
||
| r "gopkg.in/redis.v3" | ||
| ) | ||
|
|
||
| type adapter struct { | ||
| bufferSize int | ||
| redisClient *r.Client | ||
| } | ||
|
|
||
| // NewStorageAdapter returns a pointer to a new instance of a redis-based storage.Adapter. | ||
| func NewStorageAdapter(bufferSize int) (*adapter, error) { | ||
| if bufferSize <= 0 { | ||
| return nil, fmt.Errorf("Invalid buffer size: %d", bufferSize) | ||
| } | ||
| cfg, err := parseConfig(appName) | ||
| if err != nil { | ||
| log.Fatalf("config error: %s: ", err) | ||
| } | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| return &adapter{ | ||
| bufferSize: bufferSize, | ||
| redisClient: r.NewClient(&r.Options{ | ||
| Addr: fmt.Sprintf("%s:%d", cfg.RedisHost, cfg.RedisPort), | ||
| Password: cfg.RedisPassword, // "" == no password | ||
| DB: int64(cfg.RedisDB), | ||
| }), | ||
| }, nil | ||
| } | ||
|
|
||
| // Write adds a log message to to an app-specific list in redis using ring-buffer-like semantics | ||
| func (a *adapter) Write(app string, message string) error { | ||
| // Note: Deliberately NOT using MULTI / transactions here since in this implementation of the | ||
| // redis client, MULTI is not safe for concurrent use by multiple goroutines. It's been advised | ||
| // by the authors of the gopkg.in/redis.v3 package to just use pipelining when possible... | ||
| // and here that is technically possible. In the WORST case scenario, not having transactions | ||
| // means we may momentarily have more than the desired number of log entries in the list / | ||
| // buffer, but an LTRIM will eventually correct that, bringing the list / buffer back down to | ||
| // its desired max size. | ||
| pipeline := a.redisClient.Pipeline() | ||
| if err := pipeline.RPush(app, message).Err(); err != nil { | ||
| return err | ||
| } | ||
| if err := pipeline.LTrim(app, int64(-1*a.bufferSize), -1).Err(); err != nil { | ||
| return err | ||
| } | ||
| if _, err := pipeline.Exec(); err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
|
|
||
| // Read retrieves a specified number of log lines from an app-specific list in redis | ||
| func (a *adapter) Read(app string, lines int) ([]string, error) { | ||
| stringSliceCmd := a.redisClient.LRange(app, int64(-1*lines), -1) | ||
| result, err := stringSliceCmd.Result() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| if len(result) > 0 { | ||
| return result, nil | ||
| } | ||
| return nil, fmt.Errorf("Could not find logs for '%s'", app) | ||
| } | ||
|
|
||
| // Destroy deletes an app-specific list from redis | ||
| func (a *adapter) Destroy(app string) error { | ||
| if err := a.redisClient.Del(app).Err(); err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
|
|
||
| func (a *adapter) Reopen() error { | ||
| // No-op | ||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,128 @@ | ||
| package redis | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "testing" | ||
| ) | ||
|
|
||
| const app string = "test-app" | ||
|
|
||
| func TestReadFromNonExistingApp(t *testing.T) { | ||
| // Initialize a new storage adapter | ||
| a, err := NewStorageAdapter(10) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // No logs have been written; there should be no redis list for app | ||
| messages, err := a.Read(app, 10) | ||
| if messages != nil { | ||
| t.Error("Expected no messages, but got some") | ||
| } | ||
| if err == nil || err.Error() != fmt.Sprintf("Could not find logs for '%s'", app) { | ||
| t.Error("Did not receive expected error message") | ||
| } | ||
| } | ||
|
|
||
| func TestWithBadBufferSizes(t *testing.T) { | ||
| // Initialize with invalid buffer sizes | ||
| for _, size := range []int{-1, 0} { | ||
| a, err := NewStorageAdapter(size) | ||
| if a != nil { | ||
| t.Error("Expected no storage adapter, but got one") | ||
| } | ||
| if err == nil || err.Error() != fmt.Sprintf("Invalid buffer size: %d", size) { | ||
| t.Error("Did not receive expected error message") | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func TestLogs(t *testing.T) { | ||
| // Initialize with small buffers | ||
| a, err := NewStorageAdapter(10) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // And write a few logs to it, but do NOT fill it up | ||
| for i := 0; i < 5; i++ { | ||
| if err := a.Write(app, fmt.Sprintf("message %d", i)); err != nil { | ||
| t.Error(err) | ||
| } | ||
| } | ||
| // Read more logs than there are | ||
| messages, err := a.Read(app, 8) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // Should only get as many messages as we actually have | ||
| if len(messages) != 5 { | ||
| t.Errorf("only expected 5 log messages, got %d", len(messages)) | ||
| } | ||
| // Read fewer logs than there are | ||
| messages, err = a.Read(app, 3) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // Should get the 3 MOST RECENT logs | ||
| if len(messages) != 3 { | ||
| t.Errorf("only expected 5 log messages, got %d", len(messages)) | ||
| } | ||
| for i := 0; i < 3; i++ { | ||
| expectedMessage := fmt.Sprintf("message %d", i+2) | ||
| if messages[i] != expectedMessage { | ||
| t.Errorf("expected: \"%s\", got \"%s\"", expectedMessage, messages[i]) | ||
| } | ||
| } | ||
| // Overfill the buffer | ||
| for i := 5; i < 11; i++ { | ||
| if err := a.Write(app, fmt.Sprintf("message %d", i)); err != nil { | ||
| t.Error(err) | ||
| } | ||
| } | ||
| // Read more logs than the buffer can hold | ||
| messages, err = a.Read(app, 20) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // Should only get as many messages as the buffer can hold | ||
| if len(messages) != 10 { | ||
| t.Errorf("only expected 10 log messages, got %d", len(messages)) | ||
| } | ||
| // And they should only be the 10 MOST RECENT logs | ||
| for i := 0; i < 10; i++ { | ||
| expectedMessage := fmt.Sprintf("message %d", i+1) | ||
| if messages[i] != expectedMessage { | ||
| t.Errorf("expected: \"%s\", got \"%s\"", expectedMessage, messages[i]) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func TestDestroy(t *testing.T) { | ||
| a, err := NewStorageAdapter(10) | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| // Write a log to create the file | ||
| if err := a.Write(app, "Hello, log!"); err != nil { | ||
| t.Error(err) | ||
| } | ||
| // A redis list should exist for the app | ||
| exists, err := a.redisClient.Exists(app).Result() | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| if !exists { | ||
| t.Error("Log redis list was expected to exist, but doesn't.") | ||
| } | ||
| // Now destroy it | ||
| if err := a.Destroy(app); err != nil { | ||
| t.Error(err) | ||
| } | ||
| // Now check that the redis list no longer exists | ||
| exists, err = a.redisClient.Exists(app).Result() | ||
| if err != nil { | ||
| t.Error(err) | ||
| } | ||
| if exists { | ||
| t.Error("Log redis list still exist, but was expected not to.") | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,24 @@ | ||
| package redis | ||
|
|
||
| import ( | ||
| "github.com/kelseyhightower/envconfig" | ||
| ) | ||
|
|
||
| const ( | ||
| appName = "logger" | ||
| ) | ||
|
|
||
| type config struct { | ||
| RedisHost string `envconfig:"DEIS_LOGGER_REDIS_SERVICE_HOST" default:""` | ||
| RedisPort int `envconfig:"DEIS_LOGGER_REDIS_SERVICE_PORT" default:"6379"` | ||
| RedisPassword string `envconfig:"DEIS_LOGGER_REDIS_PASSWORD" default:""` | ||
| RedisDB int `envconfig:"DEIS_LOGGER_REDIS_DB" default:"0"` | ||
| } | ||
|
|
||
| func parseConfig(appName string) (*config, error) { | ||
| ret := new(config) | ||
| if err := envconfig.Process(appName, ret); err != nil { | ||
| return nil, err | ||
| } | ||
| return ret, nil | ||
| } |