1 | #!/usr/local/bin/python |
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2 | |
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3 | import sys |
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4 | import re |
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5 | import os |
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6 | |
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7 | from optparse import OptionParser |
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8 | from federation.remote_service import service_caller |
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9 | from federation import topdl |
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10 | |
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11 | class constraint: |
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12 | def __init__(self, name=None, required=False, accepts=None, provides=None, |
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13 | match=None): |
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14 | self.name = name |
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15 | self.required = required |
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16 | self.accepts = accepts or [] |
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17 | self.provides = provides or [] |
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18 | self.match = match |
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19 | |
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20 | def __str__(self): |
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21 | return "%s:%s:%s:%s" % (self.name, self.required, |
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22 | ",".join(self.provides), ",".join(self.accepts)) |
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23 | |
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24 | |
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25 | def add_to_map(exp, mark, provides, accepts): |
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26 | """ |
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27 | Create a constraint from a string of the form |
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28 | name:required:provides:accepts |
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29 | where name is the name of the node in the current topology, if the second |
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30 | field is "required" this is a required constraint, a list of attributes |
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31 | that this connection point provides and a list that it accepts. The |
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32 | provides and accepts lists are comma-separated. Note that the string |
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33 | passed in as exp should have whitespace removed. The constraint is added to |
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34 | the mark dict under the name key and entries in the provides and accepts |
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35 | are made to teh constraing for each attribute that it provides or accepts. |
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36 | """ |
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37 | nn, r, p, a = exp.split(":") |
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38 | p = p.split(",") |
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39 | a = a.split(",") |
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40 | c = constraint(name=nn, required=(r == 'required'), provides=p, accepts=a) |
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41 | mark[nn] = c |
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42 | |
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43 | for attr, dict in ((p, provides), (a, accepts)): |
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44 | for a in attr: |
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45 | if a not in dict: dict[a] = [c] |
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46 | else: dict[a].append(c) |
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47 | |
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48 | def make_new_name(names, prefix="name"): |
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49 | """ |
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50 | Generate an identifier not present in names by appending an integer to |
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51 | prefix. The new name is inserted into names and returned. |
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52 | """ |
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53 | i = 0 |
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54 | n = "%s%d" % (prefix,i) |
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55 | while n in names: |
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56 | i += 1 |
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57 | n = "%s%d" % (prefix,i) |
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58 | names.add(n) |
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59 | return n |
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60 | |
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61 | def add_interfaces(top, mark): |
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62 | """ |
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63 | Add unconnected interfaces to the nodes whose names are keys in the mark |
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64 | dict. As the interface is added change the name field of the contstraint |
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65 | in mark into a tuple containing the node name, interface name, and topology |
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66 | in which they reside. |
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67 | """ |
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68 | for e in top.elements: |
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69 | if e.name in mark: |
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70 | con = mark[e.name] |
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71 | ii = make_new_name(set([x.name for x in e.interface]), "inf") |
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72 | e.interface.append( |
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73 | topdl.Interface(substrate=[], name=ii, element=e)) |
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74 | con.name = (e.name, ii, top) |
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75 | |
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76 | def localize_names(top, names, marks): |
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77 | """ |
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78 | Take a topology and rename any substrates or elements that share a name |
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79 | with an existing computer or substrate. Keep the original name as a |
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80 | localized_name attribute. In addition, remap any constraints or interfaces |
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81 | that point to the old name over to the new one. Constraints are found in |
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82 | the marks dict, indexed by node name. Those constraints name attributes |
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83 | have already been converted to triples (node name, interface name, |
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84 | topology) so only the node name needs to be changed. |
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85 | """ |
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86 | sub_map = { } |
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87 | for s in top.substrates: |
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88 | s.set_attribute('localized_name', s.name) |
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89 | if s.name in names: |
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90 | sub_map[s.name] = n = make_new_name(names, "substrate") |
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91 | s.name = n |
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92 | else: |
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93 | names.add(s.name) |
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94 | |
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95 | for e in [ e for e in top.elements if isinstance(e, topdl.Computer)]: |
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96 | e.set_attribute('localized_name', e.name) |
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97 | if e.name in names: |
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98 | nn= make_new_name(names, "computer") |
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99 | if e.name in marks: |
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100 | n, i, t = marks[e.name].name |
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101 | marks[e.name].name = (nn, i, t) |
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102 | e.name = nn |
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103 | else: |
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104 | names.add(e.name) |
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105 | |
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106 | # Interface mapping. The list comprehension creates a list of |
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107 | # substrate names where each element in the list is replaced by the |
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108 | # entry in sub_map indexed by it if present and left alone otherwise. |
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109 | for i in e.interface: |
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110 | i.substrate = [ sub_map.get(ii, ii) for ii in i.substrate ] |
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111 | |
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112 | def meet_constraints(candidates, provides, accepts): |
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113 | """ |
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114 | Try to meet all the constraints in candidates using the information in the |
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115 | provides and accepts dicts (which index constraints that provide or accept |
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116 | the given attribute). A constraint is met if it can be matched with another |
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117 | constraint that provides an attribute that the first constraint accepts. |
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118 | Only one match per pair is allowed, and we always prefer matching a |
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119 | required constraint to an unreqired one. If all the candidates can be |
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120 | matches, return True and return False otherwise. |
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121 | """ |
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122 | got_all = True |
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123 | for c in candidates: |
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124 | if not c.match: |
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125 | match = None |
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126 | for a in c.accepts: |
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127 | for can in provides.get(a,[]): |
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128 | # A constraint cannot satisfy itself, nor do we allow loops |
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129 | # within the same topology. This also excludes matched |
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130 | # constraints. |
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131 | if can.name != c.name and can.name[2] != c.name[2] and \ |
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132 | not can.match: |
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133 | match = can |
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134 | # Within providers, prefer matches against required |
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135 | # composition points |
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136 | if can.required: |
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137 | break |
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138 | # Within acceptance categories, prefer matches against required |
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139 | # composition points |
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140 | if match and match.required: |
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141 | break |
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142 | |
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143 | # Done checking all possible matches. |
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144 | if match: |
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145 | match.match = c |
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146 | c.match = match |
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147 | else: |
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148 | got_all = False |
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149 | return got_all |
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150 | |
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151 | def remote_ns2topdl(uri, desc, cert): |
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152 | """ |
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153 | Call a remote service to convert the ns2 to topdl (and in fact all the way |
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154 | to a topdl.Topology. |
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155 | """ |
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156 | |
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157 | req = { 'description' : { 'ns2description': desc }, } |
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158 | |
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159 | try: |
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160 | r = service_caller('Ns2Topdl')(uri, req, cert) |
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161 | except: |
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162 | return None |
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163 | |
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164 | if r.has_key('Ns2TopdlResponseBody'): |
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165 | r = r['Ns2TopdlResponseBody'] |
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166 | ed = r.get('experimentdescription', None) |
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167 | if 'topdldescription' in ed: |
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168 | return topdl.Topology(**ed['topdldescription']) |
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169 | else: |
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170 | return None |
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171 | else: |
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172 | return None |
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173 | |
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174 | def connect_composition_points(top, contraints): |
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175 | """ |
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176 | top is a topology containing copies of all the topologies represented in |
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177 | the contsraints, flattened into one name space. This routine inserts the |
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178 | additional substrates required to interconnect the topology as described by |
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179 | the constraints. After the links are made, unused connection points are |
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180 | purged. |
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181 | """ |
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182 | done = set() |
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183 | for c in constraints: |
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184 | if c not in done and c.match: |
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185 | # c is an unprocessed matched constraint. Create a substrate |
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186 | # and attach it to the interfaces named by c and c.match. |
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187 | sn = make_new_name(names, "sub") |
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188 | s = topdl.Substrate(name=sn) |
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189 | connected = 0 |
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190 | # Walk through all the computers in the topology |
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191 | for e in [ e for e in top.elements \ |
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192 | if isinstance(e, topdl.Computer)]: |
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193 | # if the computer matches the computer and interface name in |
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194 | # either c or c.match, connect it. Once both computers have |
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195 | # been found and connected, exit the loop walking through all |
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196 | # computers. |
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197 | for comp, inf in (c.name[0:2], c.match.name[0:2]): |
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198 | if e.name == comp: |
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199 | for i in e.interface: |
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200 | if i.name == inf: |
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201 | i.substrate.append(sn) |
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202 | connected += 1 |
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203 | break |
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204 | break |
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205 | # Connected both, so add the substrate to the topology |
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206 | if connected == 2: |
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207 | top.substrates.append(s) |
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208 | break |
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209 | # c and c.match have been processed, so add them to the done set |
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210 | done.add(c) |
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211 | done.add(c.match) |
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212 | |
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213 | # All interfaces with matched constraints have been connected. Cull any |
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214 | # interfaces unassigned to a substrate |
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215 | for e in [ e for e in top.elements if isinstance(e, topdl.Computer)]: |
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216 | if any([ not i.substrate for i in e.interface]): |
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217 | e.interface = [ i for i in e.interface if i.substrate ] |
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218 | |
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219 | top.incorporate_elements() |
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220 | |
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221 | |
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222 | # Main line begins |
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223 | |
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224 | const_re = re.compile("\s*#\s*COMPOSITION:\s*([^:]+:[^:]+:.*)") |
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225 | |
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226 | parser = OptionParser() |
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227 | parser.add_option('--url', dest='url', default="http://localhost:13235", |
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228 | help='url of ns2 to topdl service') |
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229 | parser.add_option('--certfile', dest='cert', default=None, |
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230 | help='Certificate to use as identity') |
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231 | |
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232 | opts, args = parser.parse_args() |
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233 | |
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234 | |
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235 | if opts.cert: |
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236 | cert = opts.cert |
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237 | elif os.access(os.path.expanduser("~/.ssl/emulab.pem"), os.R_OK): |
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238 | cert = os.path.expanduser("~/.ssl/emulab.pem") |
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239 | else: |
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240 | cert = None |
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241 | |
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242 | comps = [ ] |
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243 | names = set() |
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244 | constraints = [ ] |
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245 | provides = { } |
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246 | accepts = { } |
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247 | for fn in args: |
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248 | marks = { } |
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249 | contents = "" |
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250 | try: |
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251 | f = open(fn, "r") |
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252 | for l in f: |
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253 | contents += l |
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254 | m = const_re.search(l) |
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255 | if m: |
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256 | add_to_map(re.sub('\s', '', m.group(1)), marks, provides, |
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257 | accepts) |
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258 | except EnvironmentError, e: |
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259 | print >>sys.stderr, "Error on %s: %s" % (fn, e) |
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260 | continue |
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261 | |
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262 | top = remote_ns2topdl(opts.url, contents, cert) |
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263 | if not top: |
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264 | sys.exit("Cannot create topology from: %s" % fn) |
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265 | add_interfaces(top, marks) |
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266 | localize_names(top, names, marks) |
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267 | top.incorporate_elements() |
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268 | constraints.extend(marks.values()) |
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269 | comps.append(top) |
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270 | |
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271 | # Let the user know if they messed up on specifying constraints. |
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272 | if any([ not isinstance(c.name, tuple) for c in constraints]): |
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273 | print >>sys.stderr, "nodes not found for constraints on %s" % \ |
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274 | ",".join([ c.name for c in constraints \ |
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275 | if isinstance(c.name, basestring)]) |
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276 | constraints = [ c for c in constraints if isinstance(c.name, tuple )] |
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277 | |
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278 | # Now the various components live in the same namespace and are marked with |
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279 | # their composition requirements. |
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280 | |
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281 | if not meet_constraints([c for c in constraints if c.required], |
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282 | provides, accepts): |
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283 | sys.exit("Could not meet all required constraints") |
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284 | meet_constraints([ c for c in constraints if not c.match ], provides, accepts) |
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285 | |
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286 | # Make a topology containing all elements and substrates from components that |
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287 | # had matches. |
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288 | comp = topdl.Topology() |
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289 | for t in set([ c.name[2] for c in constraints if c.match]): |
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290 | comp.elements.extend([e.clone() for e in t.elements]) |
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291 | comp.substrates.extend([s.clone() for s in t.substrates]) |
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292 | |
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293 | # Add substrates and connections corresponding to composition points |
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294 | connect_composition_points(comp, constraints) |
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295 | |
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296 | print topdl.topology_to_xml(comp, top='experiment') |
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