From 5be4c31726a9973cbd102d7d9643ffdd247b9bd3 Mon Sep 17 00:00:00 2001
From: Phil Crump <phil@philcrump.co.uk>
Date: Sun, 6 May 2018 16:16:00 +0000
Subject: [PATCH] Habitat queue: Requeue after network issue.

---
 habitat.c     | 44 ++++++++++++++++++++++++++++++++++---------
 lifo_buffer.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 lifo_buffer.h |  2 ++
 3 files changed, 88 insertions(+), 10 deletions(-)

diff --git a/habitat.c b/habitat.c
index 10951df..830f390 100644
--- a/habitat.c
+++ b/habitat.c
@@ -49,7 +49,7 @@ void hash_to_hex( unsigned char *hash, char *line )
     line[64] = '\0';
 }
 
-void UploadTelemetryPacket( received_t * t )
+bool UploadTelemetryPacket( received_t * t )
 {
     CURL *curl;
     CURLcode res;
@@ -59,6 +59,7 @@ void UploadTelemetryPacket( received_t * t )
     curl = curl_easy_init(  );
     if ( curl )
     {
+        bool result;
         char url[200];
         char base64_data[1000];
         size_t base64_length;
@@ -142,7 +143,13 @@ void UploadTelemetryPacket( received_t * t )
 				if (http_resp != 201 && http_resp != 403 && http_resp != 409)
 				{
 					LogMessage("Unexpected HTTP response %ld for URL '%s'\n", http_resp, url);
+                    result = false;
 				}
+                else
+                {
+                    /* Everything performing nominally (even if we didn't successfully insert this time) */
+                    result = true;
+                }
 			}
 			else
 			{
@@ -150,6 +157,8 @@ void UploadTelemetryPacket( received_t * t )
 				LogMessage("Failed for URL '%s'\n", url);
 				LogMessage("curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
 				LogMessage("error: %s\n", curl_error);
+                /* Likely a network error, so return false to requeue */
+                result = false;
 			}
 			
 			if (http_resp == 409)
@@ -163,6 +172,13 @@ void UploadTelemetryPacket( received_t * t )
         // always cleanup
         curl_slist_free_all( headers );
         curl_easy_cleanup( curl );
+
+        return result;
+    }
+    else
+    {
+        /* CURL error, return false so we requeue */
+        return false;
     }
 }
 
@@ -180,23 +196,33 @@ void *HabitatLoop( void *vars )
 
             if(dequeued_telemetry_ptr != NULL)
             {
-                ChannelPrintf( dequeued_telemetry_ptr->Metadata.Channel, 6, 1, "Habitat" );
+                ChannelPrintf( dequeued_telemetry_ptr->Metadata.Channel, 6, 1, "Habitat (%d queued)", lifo_buffer_queued(&Habitat_Upload_Buffer) );
 
-                UploadTelemetryPacket( dequeued_telemetry_ptr );
+                if(UploadTelemetryPacket( dequeued_telemetry_ptr ))
+                {
+                    ChannelPrintf( dequeued_telemetry_ptr->Metadata.Channel, 6, 1, "                   " );
+                    free(dequeued_telemetry_ptr);
+                }
+                else
+                {
+                    /* Network / CURL Error, requeue packet */
+                    ChannelPrintf( dequeued_telemetry_ptr->Metadata.Channel, 6, 1, "Habitat Net Error! " );
 
-                ChannelPrintf( dequeued_telemetry_ptr->Metadata.Channel, 6, 1, "       " );
-
-                free(dequeued_telemetry_ptr);
+                    if(!lifo_buffer_requeue(&Habitat_Upload_Buffer, dequeued_telemetry_ptr))
+                    {
+                        /* Requeue failed, drop packet */
+                        free(dequeued_telemetry_ptr);
+                    }
+                }
             }
             else
             {
-                /* We've been asked to quit */
+                /* NULL returned: We've been asked to quit */
+                /* Don't bother free()ing stuff, as application is quitting */
                 break;
             }
         }
     }
 
-    LogMessage( "Habitat thread closing\n" );
-
     return NULL;
 }
diff --git a/lifo_buffer.c b/lifo_buffer.c
index 0fc3315..fe6236d 100644
--- a/lifo_buffer.c
+++ b/lifo_buffer.c
@@ -20,6 +20,26 @@ void lifo_buffer_init(lifo_buffer_t *buf, uint32_t length)
     pthread_mutex_unlock(&buf->Mutex);
 }
 
+uint32_t lifo_buffer_queued(lifo_buffer_t *buf)
+{
+    uint32_t result;
+
+    pthread_mutex_lock(&buf->Mutex);
+
+    if(buf->Head >= buf->Tail)
+    {
+        result = buf->Head - buf->Tail;
+    }
+    else
+    {
+        result = buf->Head + (buf->Length - buf->Tail);
+    }
+
+    pthread_mutex_unlock(&buf->Mutex);
+
+    return result;
+}
+
 /* Lossy when buffer is full */
 void lifo_buffer_push(lifo_buffer_t *buf, void *data_ptr)
 {
@@ -112,4 +132,34 @@ void lifo_buffer_quitwait(lifo_buffer_t *buf)
     pthread_cond_signal(&buf->Signal);
 
     pthread_mutex_unlock(&buf->Mutex);
-}
\ No newline at end of file
+}
+/* Puts it on the bottom to avoid clogging by packet data problems, lossy when buffer is full */
+bool lifo_buffer_requeue(lifo_buffer_t *buf, void *data_ptr)
+{
+    bool result;
+
+    pthread_mutex_lock(&buf->Mutex);
+
+    /* If no space, ignore */
+    if(buf->Head!=(buf->Tail-1) && !(buf->Head==(buf->Length-1) && buf->Tail==0))
+    {
+        buf->Data[buf->Tail] = data_ptr;
+
+        if(buf->Tail==0)
+            buf->Tail=(buf->Length-1);
+        else
+            buf->Tail--;
+    
+        pthread_cond_signal(&buf->Signal);
+
+        result = true;
+    }
+    else
+    {
+        result = false;
+    }
+
+    pthread_mutex_unlock(&buf->Mutex);
+
+    return result;
+}
diff --git a/lifo_buffer.h b/lifo_buffer.h
index c4c58a7..82ff646 100644
--- a/lifo_buffer.h
+++ b/lifo_buffer.h
@@ -22,9 +22,11 @@ typedef struct
 
 /** Common functions **/
 void lifo_buffer_init(lifo_buffer_t *buf, uint32_t length);
+uint32_t lifo_buffer_queued(lifo_buffer_t *buf);
 void lifo_buffer_push(lifo_buffer_t *buf, void *data_ptr);
 void *lifo_buffer_pop(lifo_buffer_t *buf);
 void *lifo_buffer_waitpop(lifo_buffer_t *buf);
 void lifo_buffer_quitwait(lifo_buffer_t *buf);
+bool lifo_buffer_requeue(lifo_buffer_t *buf, void *data_ptr);
 
 #endif /* __LIFO_BUFFER_H__*/
\ No newline at end of file