We use New Relic RPM to monitor our apps. We also love the new Rails 3.1 asset pipeline, and have been slowly migrating our Heroku apps to the new(ish) Cedar stack.
Unfortunately, when I combined all three for the first time today, I got a nasty surprise:
-----> Preparing app for Rails asset pipeline Running: rake assets:precompile rake aborted! could not connect to server: Connection refused Is the server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432? Tasks: TOP => environment (See full trace by running task with --trace) Precompiling assets failed, enabling runtime asset compilation Injecting rails31_enable_runtime_asset_compilation Please see this article for troubleshooting help...
Sad robin! Worse, in my case, runtime asset compilation failed as well, yielding a broken app -- not that I would want it doing runtime compilation in production even if it had worked.
The troubleshooting article linked in the log output yields the clue that the environment is disabled and stubbed out during asset precompilation. New Relic RPM attempts to initialize during precompilation, and fails when it initializes ActiveRecord against the invalid stub database supplied.
Amazingly, I didn't find a fix for this when I Googled around! So here's my solution. I wrapped the newrelic.yml in some ERB to disable New Relic when the environment it depends on is missing:
<%unless ENV["NEW_RELIC_LICENSE_KEY"].nil? %> --- production: error_collector: capture_source: true enabled: true ignore_errors: ActionController::RoutingError apdex_t: 0.5 ssl: false monitor_mode: true license_key: <%= ENV["NEW_RELIC_LICENSE_KEY"] %> developer_mode: false app_name: <%= ENV["NEW_RELIC_APP_NAME"] %> transaction_tracer: record_sql: obfuscated enabled: true stack_trace_threshold: 0.5 transaction_threshold: apdex_f capture_params: false log_level: info <%end%>
In addition to fixing the problem during precompilation, this makes my local system happier when I need to check something under -e production.
Any better solutions? Leave me a tweet.
