gistfile1.lisp

; The execution macro
(defmacro exec
  "Execute a command on the shell, passing to the given function
  the lazy sequence of lines read as output, and the rest of arguments."
  [cmd pred & args]
  `(with-open [br# (BufferedReader. (InputStreamReader. (.getInputStream (.exec (Runtime/getRuntime) ~cmd))))]
     (~pred (line-seq br#) ~@args)))

; This works
(defn get-groups
  "Given a hostname, get a list of groups on that Avamar server"
  [host]
  (exec (str "get_groups.sh " host)
        #(doseq [line %1]
           (println line))))

; This works also
(defn get-clients
  "Given a hostname and group, get a list of clients for the group"
  [host group]
  (exec (str "get_clients.sh " host " " group)
        #(doseq [line %1]
           (println line))))

; This doesn't work
(defn drill-down
  "Try to do both, Fail."
  [hostname]
  (exec (str "get_groups.sh " hostname)
        #(doseq [group %1]
           (exec (str "get_clients.sh " hostname " " group)
                 #(doseq [client %1]
                    (println "Group/client:" group client))))))

; Fixed:
(defn drill-down
  "Try to do both, Win."
  [hostname]
  (exec (str "get_groups.sh " hostname)
        (fn [groups]
          (doseq [group groups]
            (exec (str "get_clients.sh " hostname " " group)
                  (fn [clients]
                    (doseq [client clients]
                      (println "Group/client:" group client))))))))