Merge lp:~cboylan/boots/boots_pager into lp:boots

[Clark Boylan]

[Clark Boylan (cboylan)]

First implementation of pager integration. I half expect this to require more work, but I am looking for comments on what the desired behaviors should be and if I should be doing this with a threaded model, etc.

A decent first step though.

[lp:~cboylan/boots/boots_pager]

97. By Clark Boylan on 2010-02-28

generate tablized output in a generator for the PlainUI.

98. By Clark Boylan on 2010-03-01

Much better version of pager integration.

99. By Clark Boylan on 2010-03-01

More pager tweaks, with auto interpretation in PlainUI.

100. By Clark Boylan on 2010-03-01

Merged in chromakode's pager auto config work and better error checking for pager integration.

[Max Goodhart (chromakode)]

Nice work!

<chromakode> in a perfect world, we could spool output to the pager immediately
 but for now, this is a decent first implementation
<clarkb> indeed

review: Approve

=== modified file 'boots/app/client_config.py'
--- boots/app/client_config.py	2010-02-27 05:40:10 +0000
+++ boots/app/client_config.py	2010-03-01 08:32:17 +0000
@@ -26,9 +26,31 @@
 options/arguments."""
 
 import optparse
-import os
+import os, os.path
 import info
 
+def find_executable(name):
+    # Search algorithm adapted from os._execvpe 
+    head, tail = os.path.split(name)
+    if head and os.path.exists(name):
+        return name
+    else:
+        if 'PATH' in os.environ:
+            envpath = os.environ['PATH']
+        else:
+            envpath = os.defpath
+        PATH = envpath.split(os.pathsep)
+        for dir in PATH:
+            fullname = os.path.join(dir, name)
+            if os.path.exists(fullname):
+                return fullname
+
+def get_auto_pager():
+    if find_executable("less"):
+        return "less -XF"
+    elif find_executable("more"):
+        return "more"    
+
 class ClientConfig(object):
     """Class used to read client configuration from files and the cli."""
 
@@ -41,7 +63,7 @@
         self._defaults = {"command":            None,
                           "database":           None,
                           "script":             None,
-                          'lingo':              'sql',
+                          "lingo":              "sql",
                           "rcfile":             info.RCFILE,
                           "host":               "localhost",
                           "port":               9306,
@@ -49,6 +71,8 @@
                           "password":           False,
                           "prompt1":            "> ",
                           "prompt2":            "+ ",
+                          "pager":              None,
+                          "pager_command":      None,
                           "terminating_char":   ";",
                           "history_length":     100,
                           "history_file":       os.path.expanduser("~/.boots_history")}
@@ -109,6 +133,11 @@
                                     type = "string",
                                     dest = "password",
                                     help = "Connect using password. If none is given, query for password")
+        self._cli_parser.add_option("--pager",
+                                    action = "store",
+                                    type = "string",
+                                    dest = "pager",
+                                    help = "Pipe query results to the specified pager.")
         self._cli_parser.add_option("-t", "--terminatingchar",
                                     action = "store",
                                     type = "string",
@@ -154,6 +183,14 @@
         
         self._dict.update(from_file)
         self._dict.update(from_cli)
+        self._interpret_options()
+ 
+    def _interpret_options(self):
+        # Interpret options
+        if self["pager"] == "auto":
+            self["pager_command"] = get_auto_pager()
+        elif self["pager"]:
+            self["pager_command"] = self["pager"]
 
     def get_file_conf(self, filepath):
         """Read a configuration from the specified file. Return a dict."""

=== modified file 'boots/lib/ui/plain.py'
--- boots/lib/ui/plain.py	2010-02-28 06:24:11 +0000
+++ boots/lib/ui/plain.py	2010-03-01 08:32:17 +0000
@@ -28,6 +28,8 @@
 import os
 import time
 import readline
+import subprocess
+import threading
  
 from boots.api.nodes.node import NodeGraph, SyncNode
 from boots.lib.ui.components.help import HelpTopic
@@ -59,6 +61,7 @@
         self.prompt2 = console.config["prompt2"]
         self.hist_file = console.config["history_file"]
         self.lingo = console.config["lingo"]
+        self.pager_command = console.config["pager_command"]
         self.last_desc = None
         self.buffer = []
         
@@ -123,6 +126,25 @@
             self.prompt1 = prompt1
             self.prompt2 = prompt2
 
+    def print_with_pager(self, text):
+        try:
+            pager = subprocess.Popen(self.pager_command.split(),
+                                     shell=False,
+                                     stdin=subprocess.PIPE)
+        except:
+            sys.stdout.write("Unable to run pager command \"{0}\". Pager disabled.\n"
+                             .format(self.pager_command))
+            self.pager_command = None
+            return False
+            
+        try:
+            pager.communicate(text)
+        except IOError:
+            # IOError is raised sometimes with large outputs
+            pass
+        
+        return True
+
     def present(self, result):
         """Print the result provided as an argument.
 
@@ -140,36 +162,46 @@
             to the string 'NULL'. This utility function performs that
             conversion."""
             return value if value is not None else "NULL"
-        
+
+        def _gen_table():
+            max_widths = map(max, [(len(column[0]), column[2]) for column in self.last_desc])
+            dashes = map(lambda x: "-"*(x+2), max_widths)
+            sep_line = "+" + "+".join(dashes) + "+\n"
+            names = (column[0] for column in self.last_desc)
+            yield sep_line
+            yield padded(names, max_widths)
+            yield sep_line
+            for row in self.buffer:
+                yield padded(map(show_NULL, row), max_widths)
+            current_time = time.time()
+            info_line = "{0} rows in set ({1:.2f} seconds).\n".format(len(self.buffer),
+                                                               current_time - result["begin_time"])
+            yield sep_line
+            yield info_line
+
         if type(result) is dict and "__server_execute_sql_query" in result:
             self.last_desc = result["info"]
             if result["result"]:
                 self.buffer.extend(result["result"])
-            else:
-                if self.buffer:
-                    max_widths = map(max, [(len(column[0]), column[2]) for column in self.last_desc])
-                    dashes = map(lambda x: "-"*(x+2), max_widths)
-                    sep_line = "+" + "+".join(dashes) + "+\n"
-                    current_time = time.time()
-                    info_line = "{0} rows in set ({1:.2f} seconds).\n".format(len(self.buffer),
-                                                                             current_time - result["begin_time"])
-                    names = (column[0] for column in self.last_desc)
-                    sys.stdout.write(sep_line)
-                    sys.stdout.write(padded(names, max_widths))
-                    sys.stdout.write(sep_line)
-                    for row in self.buffer:
-                        sys.stdout.write(padded(map(show_NULL, row), max_widths))
-                    sys.stdout.write(sep_line)
-                    sys.stdout.write(info_line)
-                    # Reset values for next result set.
-                    self.buffer = []
-        else:
-            if isinstance(result, Exception):
-                sys.stdout.write("ERROR ")
-                sys.stdout.write(" :: ".join(map(str, result.args)))
-            elif result is not None:
-                sys.stdout.write(str(result))
-                sys.stdout.write("\n")
+            elif self.buffer:
+                printed = False
+                if self.pager_command and self.console.driver.is_interactive:
+                    printed = self.print_with_pager("".join(_gen_table()))
+                
+                # Fallback if no pager set, or paging fails.
+                if not printed:
+                    for row in _gen_table():
+                        sys.stdout.write(row)
+                    
+                # Reset values for next result set.
+                self.buffer = []
+        elif isinstance(result, Exception):
+            sys.stdout.write("ERROR ")
+            sys.stdout.write(" :: ".join(map(str, result.args)))
+            sys.stdout.write("\n")
+        elif result is not None:
+            sys.stdout.write(str(result))
+            sys.stdout.write("\n")
 
     @property
     def is_interactive(self):