add undeploy_between feature

README.md

@@ -12,7 +12,7 @@ pip install deploycron
 
 # Usage
 
-There's only one function in the package now,
+There are two functions in the package now,
 
 ```python
 def deploycron(filename="", content="", override=False):
@@ -43,6 +43,123 @@ deploycron(content="* * * * * echo hello > /tmp/hello")
 deploycron(content="* * * * * echo hello > /tmp/hello", override=True)
 ```
 
+and 
+
+```python
+def undeploycron_between(start_line, stop_line, occur_start, occur_stop):
+```
+
+> Uninstall crontab parts between two lines (included).
+> If the start_line or the stop_line is not found into the installed crontab,
+> it won't be modified.
+> Returns `True` if the operation succeded and `False` if the operation failed.
+>
+>
+> `start_line` - start crontab line (the actual line, not the line number) to delimit the crontab block to remove  
+> `stop_line` - stop crontab line (the actual line, not the line number) to delimit the crontab block to remove  
+> `occur_start` - number of the occurrence of `start_line` at which the uninstall will start (1 => first occurrence)  
+> `occur_start` - number of the occurrence of `stop_line` at which the uninstall will stop  
+
+Example 1:
+```python
+from deploycron import deploycron
+
+# Crontab sample
+deploycron(content="* * * * * echo Good > /tmp/buffer")
+deploycron(content="* * * * * echo day > /tmp/buffer")
+deploycron(content="* * * * * echo to > /tmp/buffer")
+deploycron(content="* * * * * echo you > /tmp/buffer")
+deploycron(content="* * * * * echo mate > /tmp/buffer")
+
+# We want to remove from line 2 to line 4 included
+undeploycron_between("* * * * * echo day > /tmp/buffer",
+                     "* * * * * echo mate > /tmp/buffer")
+```
+
+With this script, we first get a crontab like this one :
+
+    * * * * * echo Good > /tmp/buffer
+    * * * * * echo day > /tmp/buffer
+    * * * * * echo to > /tmp/buffer
+    * * * * * echo you > /tmp/buffer
+    * * * * * echo mate > /tmp/buffer
+
+And then, after the undeploycron_between(), we get :
+
+    * * * * * echo Good > /tmp/buffer
+    * * * * * echo mate > /tmp/buffer
+
+Example 2:
+```python
+from deploycron import deploycron
+
+# Crontab sample
+deploycron(content="* * * * * echo Good > /tmp/buffer")
+deploycron(content="* * * * * echo day > /tmp/buffer")
+deploycron(content="* * * * * echo to > /tmp/buffer")
+deploycron(content="* * * * * echo you > /tmp/buffer")
+deploycron(content="* * * * * echo mate > /tmp/buffer")
+deploycron(content="* * * * * echo Good > /tmp/buffer")
+deploycron(content="* * * * * echo to > /tmp/buffer")
+deploycron(content="* * * * * echo see > /tmp/buffer")
+deploycron(content="* * * * * echo you > /tmp/buffer")
+
+# We want to remove from line 6 to line 9 included
+undeploycron_between("* * * * * echo Good > /tmp/buffer",
+                     "* * * * * echo you > /tmp/buffer",
+                     2,
+                     2)
+```
+
+This script allows us to go from this crontab :
+
+    * * * * * echo Good > /tmp/buffer
+    * * * * * echo day > /tmp/buffer
+    * * * * * echo to > /tmp/buffer
+    * * * * * echo you > /tmp/buffer
+    * * * * * echo mate > /tmp/buffer
+    * * * * * echo Good > /tmp/buffer
+    * * * * * echo to > /tmp/buffer
+    * * * * * echo see > /tmp/buffer
+    * * * * * echo you > /tmp/buffer
+
+To this one :
+
+    * * * * * echo Good > /tmp/buffer
+    * * * * * echo day > /tmp/buffer
+    * * * * * echo to > /tmp/buffer
+    * * * * * echo you > /tmp/buffer
+    * * * * * echo mate > /tmp/buffer
+
+The undeploy doesn't trigger at the first occurrence of the lines here. Instead, it triggers at the second occurrence of both `start_line` and `stop_line` as precised in the parameters.
+
+## CLI scripts
+
+The package also provides two helpers CLI scripts mapped to corresponding functions:
+
+```
+usage: deploycron_file [-h] filepath
+
+positional arguments:
+  filepath    Complete file path of the cron to deploy
+
+optional arguments:
+  -h, --help  show this help message and exit
+```
+
+and
+
+```
+usage: undeploycron_between [-h] start_line stop_line
+
+positional arguments:
+  start_line  start line to delimit the crontab block to remove
+  stop_line   stop line to delimit the crontab block to remove
+
+optional arguments:
+  -h, --help  show this help message and exit
+```
+
 ## Note
 
 Only support in unix-like system, eg. Linux/Mac

deploycron/__init__.py

@@ -26,11 +26,7 @@ def deploycron(filename="", content="", override=False):
     if override:
         installed_content = ""
     else:
-        # currently installed crontabs
-        retcode, err, installed_content = _runcmd("crontab -l")
-        if retcode != 0 and 'no crontab for' not in err:
-            raise OSError("crontab not supported in your system")
-        # merge the new crontab with the old one
+        installed_content = _get_installed_content()
         installed_content = installed_content.rstrip("\n")
     installed_crontabs = installed_content.split("\n")
     for crontab in content.split("\n"):
@@ -42,9 +38,86 @@ def deploycron(filename="", content="", override=False):
     if installed_content:
         installed_content += "\n"
     # install back
-    retcode, err, out = _runcmd("crontab", installed_content)
+    _install_content(installed_content)
+
+
+def undeploycron_between(start_line, stop_line, occur_start=1, occur_stop=1):
+    """uninstall crontab parts between two lines (included).
+    If the start_line or the stop_line is not found into the installed crontab,
+    it won't be modified.
+    `start_line` - start crontab line (the actual line, not the line number)
+    to delimit the crontab block to remove
+    `stop_line` - stop crontab line (the actual line, not the line number)
+    to delimit the crontab block to remove
+    `occur_start` - nth occurence you want to consider as start_line (ex :
+    choose 2 if you want the 2nd occurence to be chosen as start_line)
+    `occur_stop` - nth occurence you want to consider as stop_line (ex :
+    choose 2 if you want the 2nd occurence to be chosen as stop_line)
+    """
+    lines_installed = [x.strip() for x in
+                       _get_installed_content().splitlines()]
+    start_line = start_line.strip()
+    stop_line = stop_line.strip()
+    if start_line not in lines_installed:
+        return False
+    if stop_line not in lines_installed:
+        return False
+    if occur_start is None or occur_start <= 0:
+        return False
+    if occur_stop is None or occur_stop <= 0:
+        return False
+
+    # Check if stop_line is before start_line by getting their indices
+    index_start = -1
+    index_stop = -1
+    try:
+        # Find the occurence we are interested in
+        for j in range(occur_start):
+            index_start = lines_installed.index(start_line, index_start + 1)
+    except ValueError:
+        # If the occurence number is too high (nth occurrence not found)
+        return False
+    try:
+        for j in range(occur_stop):
+            index_stop = lines_installed.index(stop_line, index_stop + 1)
+    except ValueError:
+        return False
+
+    # If stop is before start, we switch them
+    if index_stop < index_start:
+        buffer_var = index_start
+        index_start = index_stop
+        index_stop = buffer_var
+
+    lines_to_install = []
+    for i in range(len(lines_installed)):
+        if i < index_start or i > index_stop:
+            lines_to_install.append(lines_installed[i])
+
+    if len(lines_to_install) > 0:
+        lines_to_install.append("")
+    content_to_install = "\n".join(lines_to_install)
+    _install_content(content_to_install)
+    return True
+
+
+def _get_installed_content():
+    """get the current installed crontab.
+    """
+    retcode, err, installed_content = _runcmd("crontab -l")
+    if retcode != 0 and b'no crontab for' not in err:
+        raise OSError("crontab not supported in your system")
+    return installed_content.decode("utf-8")
+
+
+def _install_content(content):
+    """install (replace) the given (multilines) string as new crontab...
+    """
+    retcode, err, out = _runcmd("crontab", content)
     if retcode != 0:
-        raise ValueError("failed to install crontab, check if crontab is valid")
+        raise ValueError("failed to install crontab, check if crontab is "
+                         "valid")
+
 
 def _runcmd(cmd, input=None):
     '''run shell command and return the a tuple of the cmd's return code, std error and std out

deploycron/cli_deploycron_file.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from __future__ import print_function
+import argparse
+import os
+import sys
+import deploycron
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("filepath",
+                        help="Complete file path of the cron to deploy")
+    args = parser.parse_args()
+    filepath = args.filepath
+    if not os.path.isfile(filepath):
+        print("ERROR: filepath [%s] is not a file" % filepath, file=sys.stderr)
+        sys.exit(1)
+    deploycron.deploycron(filename=filepath)
+
+
+if __name__ == "__main__":
+    main()

deploycron/cli_undeploycron_between.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from __future__ import print_function
+import argparse
+import deploycron
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("start_line",
+                        help="start line to delimit the crontab block to "
+                             "remove")
+    parser.add_argument("stop_line",
+                        help="stop line to delimit the crontab block to "
+                             "remove")
+    args = parser.parse_args()
+    start_line = args.start_line
+    stop_line = args.stop_line
+    deploycron.undeploycron_between(start_line, stop_line)
+
+
+if __name__ == "__main__":
+    main()

setup.py

@@ -17,4 +17,10 @@
         "Topic :: Utilities",
         "License :: OSI Approved :: MIT License",
     ],
+    entry_points = {
+        "console_scripts": [
+            "deploycron_file = deploycron.cli_deploycron_file:main",
+            "undeploycron_between = deploycron.cli_undeploycron_between:main"
+        ]
+    }
 )