PuppetDB 1.5 » Debugging with the Remote REPL
Included in Puppet Enterprise 3.2. A newer version is available; see the version menu above for details.
PuppetDB includes a remote REPL interface, which is disabled by default.
This is mostly of use to developers who know Clojure and are familiar with PuppetDB’s code base. It allows you to modify PuppetDB’s code on the fly. Most users should never need to use the REPL, and it should usually be left disabled for security reasons.
Enabling the REPL
To enable the REPL, you must edit PuppetDB’s config file to enable it, configure the REPL type, and choose a port:
# /etc/puppetdb/conf.d/repl.ini [repl] enabled = true type = telnet port = 8082
After configuring it, you should restart the PuppetDB service.
Connecting to a Remote REPL
Once PuppetDB is accepting remote REPL connections, you can connect to it and begin issuing low-level debugging commands and Clojure code.
For example, with a telnet type REPL configured on port 8082:
$ telnet localhost 8082 Connected to localhost. Escape character is '^]'. ;; Clojure 1.4.0 user=> (+ 1 2 3) 6
Within the REPL, you can interactively execute PuppetDB’s functions. For example, to manually compact the database:
user=> (use 'com.puppetlabs.puppetdb.cli.services) nil user=> (use 'com.puppetlabs.puppetdb.scf.storage) nil user=> (use 'clojure.java.jdbc) nil user=> (with-connection (:database configuration) (garbage-collect!)) (0)
You can also manipulate the running PuppetDB instance by redefining functions on the fly. Let’s say that for debugging purposes, you’d like to log every time a catalog is deleted. You can just redefine the existing
delete-catalog! function dynamically:
user=> (ns com.puppetlabs.puppetdb.scf.storage) nil com.puppetlabs.puppetdb.scf.storage=> (def original-delete-catalog! delete-catalog!) #'com.puppetlabs.puppetdb.scf.storage/original-delete-catalog! com.puppetlabs.puppetdb.scf.storage=> (defn delete-catalog! [catalog-hash] (log/info (str "Deleting catalog " catalog-hash)) (original-delete-catalog! catalog-hash)) #'com.puppetlabs.puppetdb.scf.storage/delete-catalog!
Now any time that function is called, you’ll see a message logged.
Note that any changes you make to the running system are transient; they don’t persist between restarts of the service. If you wish to make longer-lived changes to the code, consider running PuppetDB directly from source.