Adds tcp_keepalive options.

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.6
+FROM alpine:3.7
 MAINTAINER Peter Boothe <pboothe@google.com>
 # Install all the standard packages we need
 RUN apk update && apk add python python-dev py2-pip gcc g++ libc-dev bash rsync tar
@@ -7,21 +7,25 @@ ADD requirements.txt /requirements.txt
 RUN pip install -r requirements.txt -U
 # Install scraper
 ADD scraper.py /scraper.py
-RUN chmod +x /scraper.py
 ADD run_scraper.py /run_scraper.py
 RUN chmod +x run_scraper.py
 # The monitoring port
 EXPOSE 9090
+# Set the default values for TCP keepalive before starting the scraper.
+#
 # The :- syntax specifies a default value for the variable, so the deployment
 # need not set it unless you want to specify something other than that default.
-CMD /run_scraper.py \
-    --rsync_host=$RSYNC_HOST \
-    --rsync_port=${RSYNC_PORT:-7999} \
-    --rsync_module=$RSYNC_MODULE \
-    --bucket=$GCS_BUCKET \
-    --data_dir=scraper_data \
-    --datastore_namespace=$DATASTORE_NAMESPACE \
-    --metrics_port=${METRICS_PORT:-9090} \
-    --expected_wait_time=${EXPECTED_WAIT_TIME:-1800} \
-    --max_uncompressed_size=${MAX_UNCOMPRESSED_SIZE:-1000000000} \
-    --tarfile_directory=${TARFILE_DIRECTORY:-/tmp}
+CMD echo 60 > /proc/sys/net/ipv4/tcp_keepalive_time ; \
+    echo 30 > /proc/sys/net/ipv4/tcp_keepalive_intvl ; \
+    echo 20 > /proc/sys/net/ipv4/tcp_keepalive_probes ; \
+    /run_scraper.py \
+        --rsync_host=$RSYNC_HOST \
+        --rsync_port=${RSYNC_PORT:-7999} \
+        --rsync_module=$RSYNC_MODULE \
+        --bucket=$GCS_BUCKET \
+        --data_dir=scraper_data \
+        --datastore_namespace=$DATASTORE_NAMESPACE \
+        --metrics_port=${METRICS_PORT:-9090} \
+        --expected_wait_time=${EXPECTED_WAIT_TIME:-1800} \
+        --max_uncompressed_size=${MAX_UNCOMPRESSED_SIZE:-1000000000} \
+        --tarfile_directory=${TARFILE_DIRECTORY:-/tmp}

scraper.py

@@ -135,10 +135,11 @@ def has_one_bit_set_or_is_zero(i):
 
 
 # Use IPv4, archive mode, compression, limit total bandwidth usage to 10 Mbps,
-# don't wait too long before bailing out, and make sure to chmod the files to
-# have sensible permissions.
+# don't wait too long before bailing out, make sure to chmod the files to
+# have sensible permissions, and set SO_KEEPALIVE to ensure that long-lived
+# connections don't disappear from any NAT boxes in the middle.
 RSYNC_ARGS = ['-4', '-az', '--bwlimit=10000', '--timeout=300',
-              '--contimeout=300', '--chmod=u=rwX']
+              '--contimeout=300', '--chmod=u=rwX', '--sockopts=SO_KEEPALIVE=1']
 
 
 RemoteFile = collections.namedtuple('RemoteFile', ['filename', 'mtime'])