Source Code for Module tlib.base.SshFileRequestor

  1 -class SshFileRequestor(object): 
  2      """ 
  3      Helper class for retrieving files from remote server 
  4      """ 
  5      _host = None 
  6      _username = None 
  7      _password = None 
  8      _pkey = None 
  9      _keyfile = None 
 10   
 11      _path = None 
 12      _size = None 
 13      _start = 0 
 14       
 15      _ssh = None 
 16      _client = None 
 17      _keepalive = None 
 18   
 19 -    def __init__(self, host, username=None, password=None, pkey=None, key_filename=None, path=None, keep_alive=True): 
 20          """ 
 21          Constructor for class  
 22   
 23              @param host: remote hostname 
 24              @param username : login username 
 25              @param password : login password 
 26              @param pkey : private key used for login 
 27              @param key_filename : key file used for login 
 28              @param path : file path to be retrieved 
 29              @param keep_alive : establish only one connection 
 30   
 31          """ 
 32          self._host = host 
 33          self._username = username 
 34          self._password = password 
 35          self._pkey = pkey 
 36          self._keyfile = key_filename 
 37          self._path = path 
 38          self._keepalive = keep_alive 
 39          self.ssh_connect() 
 40   
 41 -    def __del__(self): 
 42          """ 
 43          Destructor for class 
 44          """ 
 45          self.ssh_disconnect() 
 46           
 47 -    def ssh_connect(self): 
 48          """ 
 49          Establish ssh connection 
 50          """ 
 51          if not self._ssh or not self._keepalive: 
 52              self._ssh = paramiko.SSHClient() 
 53              self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) 
 54              self._ssh.connect(hostname=self._host, username=self._username, password=self._password, pkey=self._pkey, key_filename=self._keyfile) 
 55   
 56 -    def ssh_disconnect(self): 
 57          """ 
 58          Destroy ssh connection 
 59          """ 
 60          if self._client: 
 61              self._client.close() 
 62              self._client = None 
 63          if self._ssh: 
 64              self._ssh.close() 
 65              self._ssh = None 
 66   
 67 -    def remote_tail(self, remote_host, path=None, length=0): 
 68          """ 
 69          Tail the file from a remote host (current connection used for hop purpose): 
 70          Please make sure the new ssh remote login does not require to input credentials 
 71               
 72          @param remote_host: target server where the file is located  
 73          @param path: path to file on the target server 
 74          @param length: length used for tailing 
 75   
 76          @return: a list of last n lines of file 
 77          """ 
 78          if path : 
 79              self._path = path 
 80          # make sure there's a connection 
 81          self.ssh_connect() 
 82          std_in, std_out, std_err = self._ssh.exec_command('ssh -t %s tail -%i %s' % (remote_host, length, self._path)) 
 83          lines = std_out.read().strip().split('\n') 
 84          return lines[-length:] if len(lines) > length else lines[1:] 
 85   
 86   
 87 -    def tail(self, path=None, length=0): 
 88          """ 
 89          Download file from server using sftp and returns file contents as a string 
 90   
 91          @param path: path to file on the server 
 92          @param length: length used for tailing, tailing from last position (or beginning) if length is not provided 
 93   
 94          @return: a list of last n lines of file 
 95          """ 
 96          if path: 
 97              self._path = path 
 98          if not self._client: 
 99              # make sure there's a connection 
100              self.ssh_connect() 
101              self._client = self._ssh.open_sftp() 
102   
103          fstat = self._client.stat(self._path) 
104          if length > 0: 
105              #we assume that each line may contains MAX_CHARS_IN_ONE_LINE characters at max 
106              self._start = max(0,  fstat.st_size - (MAX_CHARS_IN_ONE_LINE * length)) 
107          with self._client.open(self._path, 'r') as f: 
108              # check if we have the file size 
109              f.seek(self._start) 
110              lines = f.read().strip().split('\n') 
111           
112          self._start = fstat.st_size 
113   
114          return lines[-length:] if len(lines) > length else lines[1:] 
115