Setup ssh agent to remember private key passwords

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

.config/fish/config.fish

@@ -3,3 +3,4 @@ if status is-interactive
 end
 
 fish_add_path ~/.cargo/bin/
+fish_ssh_agent

.config/fish/functions/fish_ssh_agent.fish

@@ -0,0 +1,32 @@
+function __ssh_agent_is_started -d "check if ssh agent is already started"
+   if begin; test -f $SSH_ENV; and test -z "$SSH_AGENT_PID"; end
+      source $SSH_ENV > /dev/null
+   end
+
+   if test -z "$SSH_AGENT_PID"
+      return 1
+   end
+
+   ps -ef | grep $SSH_AGENT_PID | grep -v grep | grep -q ssh-agent
+   #pgrep ssh-agent
+   return $status
+end
+
+
+function __ssh_agent_start -d "start a new ssh agent"
+   ssh-agent -c | sed 's/^echo/#echo/' > $SSH_ENV
+   chmod 600 $SSH_ENV
+   source $SSH_ENV > /dev/null
+   true  # suppress errors from setenv, i.e. set -gx
+end
+
+
+function fish_ssh_agent --description "Start ssh-agent if not started yet, or uses already started ssh-agent."
+   if test -z "$SSH_ENV"
+      set -xg SSH_ENV $HOME/.ssh/environment
+   end
+
+   if not __ssh_agent_is_started
+      __ssh_agent_start
+   end
+end