Retry ssl connection errors (#27)

* Retry ssl connection errors and do not raise unknown errors

* Adapt test

* Review comments and changelog

* Bump minor version

* Re-raise unknown errors

* Document single concurrency

* Format changelog

CHANGELOG.md

@@ -1,6 +1,11 @@
+## 0.4.0
+
+- Add` OpenSSL::SSL::SSLError` to the list of retried exception
+- Change concurrency mode to `:single`
+
 ## 0.3.2
 
-- Add Net::OpenTimeout to the list of retried exceptions
+- Add `Net::OpenTimeout` to the list of retried exceptions
 
 ## 0.3.1
 

lib/logstash/outputs/dynatrace.rb

@@ -17,9 +17,10 @@
 require 'logstash/namespace'
 require 'logstash/outputs/base'
 require 'logstash/json'
+require 'openssl'
 
 MAX_RETRIES = 5
-PLUGIN_VERSION = '0.3.2'
+PLUGIN_VERSION = '0.4.0'
 
 module LogStash
   module Outputs
@@ -30,6 +31,8 @@ class RetryableError < StandardError;
     class Dynatrace < LogStash::Outputs::Base
       config_name 'dynatrace'
 
+      concurrency :single
+
       # The full URL of the Dynatrace log ingestion endpoint:
       # - on SaaS:    https://{your-environment-id}.live.dynatrace.com/api/v2/logs/ingest
       # - on Managed: https://{your-domain}/e/{your-environment-id}/api/v2/logs/ingest
@@ -93,9 +96,10 @@ def multi_receive(events)
 
           raise RetryableError.new "code #{response.code}" if retryable(response)
 
-        rescue Net::OpenTimeout, Net::HTTPBadResponse, RetryableError => e
+        rescue Net::OpenTimeout, Net::HTTPBadResponse, OpenSSL::SSL::SSLError, RetryableError => e
           # Net::OpenTimeout indicates a connection could not be established within the timeout period
           # Net::HTTPBadResponse indicates a protocol error
+          # OpenSSL::SSL::SSLErrorWaitReadable indicates an error establishing the ssl connection
           if retries < MAX_RETRIES
             sleep_seconds = 2 ** retries
             @logger.warn("Failed to contact dynatrace: #{e.message}. Trying again after #{sleep_seconds} seconds.")

version.rb

@@ -16,5 +16,5 @@
 
 module DynatraceConstants
   # Also required to change the version in lib/logstash/outputs/dynatrace.rb
-  VERSION = '0.3.2'
+  VERSION = '0.4.0'
 end