better handling of connection failure in nginx

Author: joelwurtz

nginx-test.conf.in

@@ -9,7 +9,7 @@ events {
     worker_connections 1024;
 }
 
-error_log  /proc/self/fd/2 debug;
+error_log  /proc/self/fd/2;
 
 http {
     default_type application/octet-stream;

src/ngx_http_redirectionio_module.h

@@ -92,7 +92,7 @@ void ngx_http_redirectionio_release_resource(ngx_reslist_t *reslist, ngx_http_re
 void ngx_http_redirectionio_read_handler(ngx_event_t *rev);
 
 void ngx_http_redirectionio_protocol_send_match(ngx_connection_t *c, ngx_http_request_t *r, ngx_http_redirectionio_ctx_t *ctx, ngx_str_t *project_key);
-void ngx_http_redirectionio_protocol_send_log(ngx_connection_t *c, ngx_http_redirectionio_log_t *log);
+ngx_int_t ngx_http_redirectionio_protocol_send_log(ngx_connection_t *c, ngx_http_redirectionio_log_t *log);
 ngx_http_redirectionio_log_t* ngx_http_redirectionio_protocol_create_log(ngx_http_request_t *r, ngx_http_redirectionio_ctx_t *ctx, ngx_str_t *project_key);
 void ngx_http_redirectionio_protocol_free_log(ngx_http_redirectionio_log_t *log);
 void ngx_http_redirectionio_protocol_send_filter_header(ngx_connection_t *c, ngx_http_request_t *r, ngx_str_t *project_key, ngx_str_t *rule_id);

src/ngx_http_redirectionio_module_filter.c

@@ -37,7 +37,7 @@ ngx_int_t ngx_http_redirectionio_match_on_response_status_header_filter(ngx_http
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http redirectionio status code update %d (on response status code)", redirect_status_code);
 
     r->headers_out.status = redirect_status_code;
-    r->headers_out.status_line.len = 0;
+    r->headers_out.status_line = (ngx_str_t)ngx_null_string;
 
     return ngx_http_redirectionio_headers_filter(r);
 }

src/ngx_http_redirectionio_module_pool.c

@@ -111,16 +111,22 @@ ngx_int_t ngx_http_redirectionio_pool_available(ngx_reslist_t *reslist, void *re
 ngx_int_t ngx_http_redirectionio_pool_available_log_handler(ngx_reslist_t *reslist, void *resource, void *data, ngx_int_t deferred) {
     ngx_http_redirectionio_log_t       *log = (ngx_http_redirectionio_log_t *)data;
     ngx_http_redirectionio_resource_t  *rr = (ngx_http_redirectionio_resource_t *)resource;
+    ngx_int_t                          rv;
 
     if (rr == NULL) {
         ngx_http_redirectionio_protocol_free_log(log);
 
         return NGX_ERROR;
     }
 
-    ngx_http_redirectionio_protocol_send_log(rr->peer.connection, log);
+    rv = ngx_http_redirectionio_protocol_send_log(rr->peer.connection, log);
     ngx_http_redirectionio_protocol_free_log(log);
-    ngx_reslist_release(reslist, rr);
+
+    if (rv != NGX_OK) {
+        ngx_reslist_invalidate(reslist, rr);
+    } else {
+        ngx_reslist_release(reslist, rr);
+    }
 
     return NGX_OK;
 }

src/ngx_http_redirectionio_protocol.c

@@ -97,13 +97,17 @@ void ngx_http_redirectionio_protocol_send_match(ngx_connection_t *c, ngx_http_re
     rv = ngx_http_redirectionio_send_protocol_header(c, project_key, REDIRECTIONIO_PROTOCOL_COMMAND_MATCH_ACTION);
 
     if (rv != NGX_OK) {
+        ctx->connection_error = 1;
+
         return;
     }
 
     // Send serialized request length
     rv = ngx_http_redirectionio_send_uint32(c, strlen(request_serialized));
 
     if (rv != NGX_OK) {
+        ctx->connection_error = 1;
+
         return;
     }
 
@@ -113,33 +117,31 @@ void ngx_http_redirectionio_protocol_send_match(ngx_connection_t *c, ngx_http_re
     free((void *)request_serialized);
 
     if (rv != NGX_OK) {
+        ctx->connection_error = 1;
+
         return;
     }
 }
 
-void ngx_http_redirectionio_protocol_send_log(ngx_connection_t *c, ngx_http_redirectionio_log_t *log) {
+ngx_int_t ngx_http_redirectionio_protocol_send_log(ngx_connection_t *c, ngx_http_redirectionio_log_t *log) {
     ssize_t     wlen = strlen(log->log_serialized);
     ngx_int_t   rv;
 
     // Send protocol header
     rv = ngx_http_redirectionio_send_protocol_header(c, &log->project_key, REDIRECTIONIO_PROTOCOL_COMMAND_LOG);
 
     if (rv != NGX_OK) {
-        return;
+        return rv;
     }
 
     // Send log length
     rv = ngx_http_redirectionio_send_uint32(c, wlen);
 
     if (rv != NGX_OK) {
-        return;
+        return rv;
     }
 
-    rv = ngx_http_redirectionio_send_string(c, log->log_serialized, wlen);
-
-    if (rv != NGX_OK) {
-        return;
-    }
+    return ngx_http_redirectionio_send_string(c, log->log_serialized, wlen);
 }
 
 ngx_http_redirectionio_log_t* ngx_http_redirectionio_protocol_create_log(ngx_http_request_t *r, ngx_http_redirectionio_ctx_t *ctx, ngx_str_t *project_key) {