Use tenacity for resolver retries

core/dovecot/Dockerfile

@@ -3,7 +3,8 @@ FROM alpine:3.7
 RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
  && apk add --no-cache \
      dovecot dovecot-sqlite dovecot-pigeonhole-plugin dovecot-pigeonhole-plugin-extdata \
-     dovecot-fts-lucene rspamd-client@testing python py-jinja2
+     dovecot-fts-lucene rspamd-client@testing python py-jinja2 py-pip \
+ && pip install tenacity
 
 COPY conf /conf
 COPY sieve /var/lib/dovecot

core/dovecot/start.py

@@ -4,27 +4,19 @@ import jinja2
 import os
 import socket
 import glob
-import time
+from tenacity import retry
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
-# Actual startup script
-i = 0
-t = 10
-while True:
-	i += 1
-	try:
-		os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-		os.environ["REDIS_ADDRESS"] = socket.gethostbyname(os.environ.get("REDIS_ADDRESS", "redis"))
-		if os.environ["WEBMAIL"] != "none":
-			os.environ["WEBMAIL_ADDRESS"] = socket.gethostbyname(os.environ.get("WEBMAIL_ADDRESS", "webmail"))
-	except socket.gaierror as err:
-		if i >= t:
-			raise
-		time.sleep(10)
-		continue
-	break
+@retry(stop=stop_after_attempt(10), wait=wait_random(min=2, max=5))
+def resolve():
+	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
+	os.environ["REDIS_ADDRESS"] = socket.gethostbyname(os.environ.get("REDIS_ADDRESS", "redis"))
+	if os.environ["WEBMAIL"] != "none":
+		os.environ["WEBMAIL_ADDRESS"] = socket.gethostbyname(os.environ.get("WEBMAIL_ADDRESS", "webmail"))
 
+# Actual startup script
+resolve()
 for dovecot_file in glob.glob("/conf/*"):
     convert(dovecot_file, os.path.join("/etc/dovecot", os.path.basename(dovecot_file)))
 

core/postfix/Dockerfile

@@ -1,6 +1,7 @@
 FROM alpine:3.7
 
-RUN apk add --no-cache postfix postfix-sqlite postfix-pcre rsyslog python py-jinja2
+RUN apk add --no-cache postfix postfix-sqlite postfix-pcre rsyslog python py-jinja2 py-pip \
+ && pip install tenacity
 
 COPY conf /conf
 COPY start.py /start.py

core/postfix/start.py

@@ -5,23 +5,16 @@ import os
 import socket
 import glob
 import shutil
-import time
+from tenacity import retry
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
+@retry(stop=stop_after_attempt(10), wait=wait_random(min=2, max=5))
+def resolve():
+	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
+
 # Actual startup script
-i = 0
-t = 10
-while True:
-	i += 1
-	try:
-		os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-	except socket.gaierror as err:
-		if i >= t:
-			raise
-		time.sleep(10)
-		continue
-	break
+resolve()
 os.environ["HOST_ANTISPAM"] = os.environ.get("HOST_ANTISPAM", "antispam:11332")
 os.environ["HOST_LMTP"] = os.environ.get("HOST_LMTP", "imap:2525")
 

services/rspamd/Dockerfile

@@ -1,6 +1,7 @@
 FROM alpine:edge
 
-RUN apk add --no-cache python py-jinja2 rspamd rspamd-controller rspamd-proxy ca-certificates
+RUN apk add --no-cache python py-jinja2 rspamd rspamd-controller rspamd-proxy ca-certificates py-pip \
+ && pip install tenacity
 
 RUN mkdir /run/rspamd
 

services/rspamd/start.py

@@ -4,23 +4,16 @@ import jinja2
 import os
 import socket
 import glob
-import time
+from tenacity import retry
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
+@retry(stop=stop_after_attempt(10), wait=wait_random(min=2, max=5))
+def resolve():
+	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
+
 # Actual startup script
-i = 0
-t = 10
-while True:
-	i += 1
-	try:
-		os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-	except socket.gaierror as err:
-		if i >= t:
-			raise
-		time.sleep(10)
-		continue
-	break
+resolve()
 if "HOST_REDIS" not in os.environ: os.environ["HOST_REDIS"] = "redis"
 
 for rspamd_file in glob.glob("/conf/*"):