After a fresh install of logstash
# /usr/share/logstash/bin/logstash-plugin install --version 3.0.5 --no-verify logstash-input-salesforce
Installing logstash-input-salesforce
Plugin version conflict, aborting
ERROR: Installation Aborted, message: Bundler could not find compatible versions for gem "faraday":
In snapshot (Gemfile.lock):
faraday (= 0.15.4)
In Gemfile:
logstash-input-rss java was resolved to 3.0.5, which depends on
faraday java
logstash-input-salesforce (= 3.0.5) java was resolved to 3.0.5, which depends on
restforce (~> 2.4.2) java was resolved to 2.4.2, which depends on
faraday (~> 0.9.0) java
octokit (~> 4) java was resolved to 4.14.0, which depends on
sawyer (>= 0.5.3, ~> 0.8.0) java was resolved to 0.8.2, which depends on
faraday (> 0.8, < 2.0) java
Running `bundle update` will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.
I am not really sure what the conflict is here. It seems that logstash wants a version of faraday that is greater than 0.8, and less than 2.0; which 0.15 fulfills.
All I can find indicates this is a problem with the way logstash is built, that the devs must change. That information is almost 2 years old at this point.