Golang Database.ListLogChunksInArtifact方法代碼示例

func GetArtifactContent(r render.Render, req *http.Request, res http.ResponseWriter, db database.Database, params martini.Params, s3bucket *s3.Bucket, artifact *model.Artifact) {
	if artifact == nil {
		JsonErrorf(r, http.StatusBadRequest, "Error: no artifact specified")
		return
	}

	switch artifact.State {
	case model.UPLOADED:
		// Fetch from S3
		reader, err := s3bucket.GetReader(artifact.S3URL)
		if err != nil {
			JsonErrorf(r, http.StatusInternalServerError, err.Error())
			return
		}
		// Ideally, we'll use a Hijacker to take over the conn so that we can employ an io.Writer
		// instead of loading the entire file into memory before writing it back out. But, for now, we
		// will run the risk of OOM if large files need to be served.
		var buf bytes.Buffer
		_, err = buf.ReadFrom(reader)
		if err != nil {
			JsonErrorf(r, http.StatusInternalServerError, "Error reading upload buffer: %s", err.Error())
			return
		}
		res.Write(buf.Bytes())
		return
	case model.UPLOADING:
		// Not done uploading to S3 yet. Error.
		r.JSON(http.StatusNotFound, map[string]string{"error": "Waiting for content to complete uploading"})
		return
	case model.APPENDING:
		fallthrough
	case model.APPEND_COMPLETE:
		// Pick from log chunks
		logChunks, err := db.ListLogChunksInArtifact(artifact.Id)
		if err != nil {
			JsonErrorf(r, http.StatusInternalServerError, err.Error())
			return
		}
		var buf bytes.Buffer
		for _, logChunk := range logChunks {
			buf.WriteString(logChunk.Content)
		}
		res.Write(buf.Bytes())
		return
	case model.WAITING_FOR_UPLOAD:
		// Not started yet. Error
		JsonErrorf(r, http.StatusNotFound, "Waiting for content to get uploaded")
		return
	}
}

// Merges all of the individual chunks into a single object and stores it on s3.
// The log chunks are stored in the database, while the object is uploaded to s3.
func MergeLogChunks(artifact *model.Artifact, db database.Database, s3bucket *s3.Bucket) error {
	switch artifact.State {
	case model.APPEND_COMPLETE:
		// TODO: Reimplement using GorpDatabase
		// If the file is empty, don't bother creating an object on S3.
		if artifact.Size == 0 {
			artifact.State = model.CLOSED_WITHOUT_DATA
			artifact.S3URL = ""

			// Conversion between *DatabaseEror and error is tricky. If we don't do this, a nil
			// *DatabaseError can become a non-nil error.
			return db.UpdateArtifact(artifact).GetError()
		}

		// XXX Do we need to commit here or is this handled transparently?
		artifact.State = model.UPLOADING
		if err := db.UpdateArtifact(artifact); err != nil {
			return err
		}

		logChunks, err := db.ListLogChunksInArtifact(artifact.Id)
		if err != nil {
			return err
		}

		r, w := io.Pipe()
		errChan := make(chan error)
		uploadCompleteChan := make(chan bool)
		fileName := artifact.DefaultS3URL()

		// Asynchronously upload the object to s3 while reading from the r, w
		// pipe. Thus anything written to "w" will be sent to S3.
		go func() {
			defer close(errChan)
			defer close(uploadCompleteChan)
			defer r.Close()
			if err := s3bucket.PutReader(fileName, r, artifact.Size, "binary/octet-stream", s3.PublicRead); err != nil {
				errChan <- fmt.Errorf("Error uploading to S3: %s", err)
				return
			}

			uploadCompleteChan <- true
		}()

		for _, logChunk := range logChunks {
			w.Write([]byte(logChunk.Content))
		}

		w.Close()

		// Wait either for S3 upload to complete or for it to fail with an error.
		// XXX This is a long operation and should probably be asynchronous from the
		// actual HTTP request, and the client should poll to check when its uploaded.
		select {
		case _ = <-uploadCompleteChan:
			artifact.State = model.UPLOADED
			artifact.S3URL = fileName
			if err := db.UpdateArtifact(artifact); err != nil {
				return err
			}

			// From this point onwards, we will not send back any errors back to the user. If we are
			// unable to delete logchunks, we log it to Sentry instead.
			if n, err := db.DeleteLogChunksForArtifact(artifact.Id); err != nil {
				// TODO: Send this error to Sentry
				log.Printf("Error deleting logchunks for artifact %d: %v\n", artifact.Id, err)
				return nil
			} else if n != int64(len(logChunks)) {
				// TODO: Send this error to Sentry
				log.Printf("Mismatch in number of logchunks while deleting logchunks for artifact %d:"+
					"Expected: %d Actual: %d\n", artifact.Id, len(logChunks), n)
			}

			return nil
		case err := <-errChan:
			return err
		}

	case model.WAITING_FOR_UPLOAD:
		fallthrough
	case model.ERROR:
		fallthrough
	case model.APPENDING:
		fallthrough
	case model.UPLOADED:
		fallthrough
	case model.UPLOADING:
		return fmt.Errorf("Artifact can only be merged when in APPEND_COMPLETE state, but state is %s", artifact.State)
	default:
		return fmt.Errorf("Illegal artifact state! State code is %d", artifact.State)
	}
}