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GUACAMOLE-623: Send typed data to Kubernetes via the STDIN channel.

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This commit is contained in:
Michael Jumper 2018-09-10 02:16:36 -07:00
parent f35517b3ff
commit b7c938c239
2 changed files with 164 additions and 13 deletions
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151
src/protocols/kubernetes/kubernetes.c
View File

@ -77,6 +77,127 @@ static void guac_kubernetes_receive_data(guac_client* client,
}
/**
* Requests that the given data be sent along the given channel to the
* Kubernetes server when the WebSocket connection is next available for
* writing. If the WebSocket connection has not been available for writing for
* long enough that the outbound message buffer is full, the request to send
* this particular message will be dropped.
*
* @param client
* The guac_client associated with the Kubernetes connection.
*
* @param channel
* The Kubernetes channel on which to send the message,
* such as GUAC_KUBERNETES_CHANNEL_STDIN.
*
* @param data
* A buffer containing the data to send.
*
* @param length
* The number of bytes to send.
*/
static void guac_kubernetes_send_message(guac_client* client,
int channel, const char* data, int length) {
guac_kubernetes_client* kubernetes_client =
(guac_kubernetes_client*) client->data;
pthread_mutex_lock(&(kubernetes_client->outbound_message_lock));
/* Add message to buffer if space is available */
if (kubernetes_client->outbound_messages_waiting
< GUAC_KUBERNETES_MAX_OUTBOUND_MESSAGES) {
/* Calculate storage position of next message */
int index = (kubernetes_client->outbound_messages_top
+ kubernetes_client->outbound_messages_waiting)
% GUAC_KUBERNETES_MAX_OUTBOUND_MESSAGES;
/* Obtain pointer to message slot at calculated position */
guac_kubernetes_message* message =
&(kubernetes_client->outbound_messages[index]);
/* Copy details of message into buffer */
message->channel = channel;
memcpy(message->data, data, length);
message->length = length;
/* One more message is now waiting */
kubernetes_client->outbound_messages_waiting++;
/* Notify libwebsockets that we need a callback to send pending
* messages */
lws_callback_on_writable(kubernetes_client->wsi);
lws_cancel_service(kubernetes_client->context);
}
/* Warn if data has to be dropped */
else
guac_client_log(client, GUAC_LOG_WARNING, "Send buffer could not be "
"flushed in time to handle additional data. Outbound "
"message dropped.");
pthread_mutex_unlock(&(kubernetes_client->outbound_message_lock));
}
/**
* Writes the oldest pending message within the outbound message queue,
* as scheduled with guac_kubernetes_send_message(), removing that message
* from the queue. This function MAY NOT be invoked outside the libwebsockets
* event callback and MUST only be invoked in the context of a
* LWS_CALLBACK_CLIENT_WRITEABLE event. If no messages are pending, this
* function has no effect.
*
* @param client
* The guac_client associated with the Kubernetes connection.
*
* @return
* true if messages still remain to be written within the outbound message
* queue, false otherwise.
*/
static bool guac_kubernetes_write_pending_message(guac_client* client) {
bool messages_remain;
guac_kubernetes_client* kubernetes_client =
(guac_kubernetes_client*) client->data;
pthread_mutex_lock(&(kubernetes_client->outbound_message_lock));
/* Send one message from top of buffer */
if (kubernetes_client->outbound_messages_waiting > 0) {
/* Obtain pointer to message at top */
int top = kubernetes_client->outbound_messages_top;
guac_kubernetes_message* message =
&(kubernetes_client->outbound_messages[top]);
/* Write message including channel index */
lws_write(kubernetes_client->wsi,
((unsigned char*) message) + LWS_PRE,
message->length + 1, LWS_WRITE_BINARY);
/* Advance top to next message */
kubernetes_client->outbound_messages_top++;
kubernetes_client->outbound_messages_top %=
GUAC_KUBERNETES_MAX_OUTBOUND_MESSAGES;
/* One less message is waiting */
kubernetes_client->outbound_messages_waiting--;
}
/* Record whether messages remained at time of completion */
messages_remain = (kubernetes_client->outbound_messages_waiting > 0);
pthread_mutex_unlock(&(kubernetes_client->outbound_message_lock));
return messages_remain;
}
/**
* Callback invoked by libwebsockets for events related to a WebSocket being
* used for communicating with an attached Kubernetes pod.
@ -132,8 +253,14 @@ static int guac_kubernetes_lws_callback(struct lws* wsi,
guac_kubernetes_receive_data(client, (const char*) in, length);
break;
/* TODO: Only send data here. Request callback for writing via lws_callback_on_writable(some struct lws*) */
/* WebSocket is ready for writing */
case LWS_CALLBACK_CLIENT_WRITEABLE:
/* Send any pending messages, requesting another callback if
* yet more messages remain */
if (guac_kubernetes_write_pending_message(client))
lws_callback_on_writable(wsi);
break;
/* TODO: Add configure test */
@ -189,14 +316,15 @@ static void* guac_kubernetes_input_thread(void* data) {
guac_kubernetes_client* kubernetes_client =
(guac_kubernetes_client*) client->data;
char buffer[8192];
char buffer[GUAC_KUBERNETES_MAX_MESSAGE_SIZE];
int bytes_read;
/* Write all data read */
while ((bytes_read = guac_terminal_read_stdin(kubernetes_client->term, buffer, sizeof(buffer))) > 0) {
/* TODO: Send to Kubernetes */
guac_terminal_write(kubernetes_client->term, buffer, bytes_read);
/* Send received data to Kubernetes along STDIN channel */
guac_kubernetes_send_message(client, GUAC_KUBERNETES_CHANNEL_STDIN,
buffer, bytes_read);
}
@ -206,8 +334,6 @@ static void* guac_kubernetes_input_thread(void* data) {
void* guac_kubernetes_client_thread(void* data) {
struct lws_context* context = NULL;
guac_client* client = (guac_client*) data;
guac_kubernetes_client* kubernetes_client =
(guac_kubernetes_client*) client->data;
@ -297,15 +423,15 @@ void* guac_kubernetes_client_thread(void* data) {
}
/* Create libwebsockets context */
context = lws_create_context(&context_info);
if (!context) {
kubernetes_client->context = lws_create_context(&context_info);
if (!kubernetes_client->context) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
"Initialization of libwebsockets failed");
goto fail;
}
/* FIXME: Generate path dynamically */
connection_info.context = context;
connection_info.context = kubernetes_client->context;
connection_info.path = "/api/v1/namespaces/default/pods/my-shell-68974bb7f7-rpjgr/attach?container=my-shell&stdin=true&stdout=true&tty=true";
/* Open WebSocket connection to Kubernetes */
@ -329,7 +455,8 @@ void* guac_kubernetes_client_thread(void* data) {
while (client->state == GUAC_CLIENT_RUNNING) {
/* Cease polling libwebsockets if an error condition is signalled */
if (lws_service(context, 1000) < 0)
if (lws_service(kubernetes_client->context,
GUAC_KUBERNETES_SERVICE_INTERVAL) < 0)
break;
}
@ -350,8 +477,8 @@ fail:
guac_common_recording_free(kubernetes_client->recording);
/* Free WebSocket context if successfully allocated */
if (context != NULL)
lws_context_destroy(context);
if (kubernetes_client->context != NULL)
lws_context_destroy(kubernetes_client->context);
guac_client_log(client, GUAC_LOG_INFO, "Kubernetes connection ended.");
return NULL;

26
src/protocols/kubernetes/kubernetes.h
View File

@ -55,6 +55,13 @@
*/
#define GUAC_KUBERNETES_CHANNEL_RESIZE 4
/**
* The maximum amount of data to include in any particular WebSocket message
* to Kubernetes. This excludes the storage space required for the channel
* index.
*/
#define GUAC_KUBERNETES_MAX_MESSAGE_SIZE 1024
/**
* The maximum number of messages to allow within the outbound message buffer.
* If messages are sent despite the buffer being full, those messages will be
@ -62,11 +69,23 @@
*/
#define GUAC_KUBERNETES_MAX_OUTBOUND_MESSAGES 8
/**
* The maximum number of milliseconds to wait for a libwebsockets event to
* occur before entering another iteration of the libwebsockets event loop.
*/
#define GUAC_KUBERNETES_SERVICE_INTERVAL 1000
/**
* An outbound message to be received by Kubernetes over WebSocket.
*/
typedef struct guac_kubernetes_message {
/**
* lws_write() requires leading padding of LWS_PRE bytes to provide
* scratch space for WebSocket framing.
*/
uint8_t _padding[LWS_PRE];
/**
* The index of the channel receiving the data, such as
* GUAC_KUBERNETES_CHANNEL_STDIN.
@ -77,7 +96,7 @@ typedef struct guac_kubernetes_message {
* The data that should be sent to Kubernetes (along with the channel
* index).
*/
char data[1024];
char data[GUAC_KUBERNETES_MAX_MESSAGE_SIZE];
/**
* The length of the data to be sent, excluding the channel index.
@ -96,6 +115,11 @@ typedef struct guac_kubernetes_client {
*/
guac_kubernetes_settings* settings;
/**
* The libwebsockets context associated with the connected WebSocket.
*/
struct lws_context* context;
/**
* The connected WebSocket.
*/