Enable GIT_TRACE/GIT_TRACE_PACKET/GIT_TRACE_PERFORMANCE by providing the git_trace_log_file config key59-git-tracing

The value of the variable if present must be a writable absolute path. If it’s
not the case we log a proper message and not enable tracing to not throw output to the users.

2 files changed, 30 insertions, 0 deletions

diff --git a/lib/gitlab_config.rb b/lib/gitlab_config.rb
index beaf173..781c706 100644
--- a/lib/gitlab_config.rb
+++ b/lib/gitlab_config.rb
@@ -50,4 +50,8 @@ class GitlabConfig
   def git_annex_enabled?
     @config['git_annex_enabled'] ||= false
   end
+
+  def git_trace_log_file
+    @config['git_trace_log_file']
+  end
 end
diff --git a/lib/gitlab_shell.rb b/lib/gitlab_shell.rb
index 971b22f..f72ce74 100644
--- a/lib/gitlab_shell.rb
+++ b/lib/gitlab_shell.rb
@@ -1,4 +1,5 @@
 require 'shellwords'
+require 'pathname'
 
 require_relative 'gitlab_net'
 
@@ -150,6 +151,14 @@ class GitlabShell
       env.merge!({ 'GIT_ANNEX_SHELL_LIMITED' => '1' })
     end
 
+    if git_trace_available?
+      env.merge!({
+        'GIT_TRACE' => @config.git_trace_log_file,
+        'GIT_TRACE_PACKET' => @config.git_trace_log_file,
+        'GIT_TRACE_PERFORMANCE' => @config.git_trace_log_file,
+      })
+    end
+
     Kernel::exec(env, *args, unsetenv_others: true)
   end
 
@@ -232,6 +241,23 @@ class GitlabShell
     end
   end
 
+  def git_trace_available?
+    return false unless @config.git_trace_log_file
+
+    if Pathname(@config.git_trace_log_file).relative?
+      $logger.warn "gitlab-shell: is configured to trace git commands with #{@config.git_trace_log_file.inspect} but an absolute path needs to be provided"
+      return false
+    end
+
+    begin
+      File.open(@config.git_trace_log_file, 'a') { nil }
+      return true
+    rescue => ex
+      $logger.warn "gitlab-shell: is configured to trace git commands with #{@config.git_trace_log_file.inspect} but it's not possible to write in that path #{ex.message}"
+      return false
+    end
+  end
+
   def repo_path=(repo_path)
     raise ArgumentError, "Repository path not provided. Please make sure you're using GitLab v8.10 or later." unless repo_path
     raise InvalidRepositoryPathError if File.absolute_path(repo_path) != repo_path