Manual:Scripting Tips and Tricks

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Revision as of 12:44, 24 August 2018 by Marisb (talk | contribs) (Always check what value and type command returns)
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Applies to RouterOS: any

How to define empty array

Get values for properties if 'get' command is not available

For example, how do you get usable output for scripting from /interface wireless info hw-info command? Use as-value:

[admin@1p_DUT_wAP ac] /interface wireless info> :put [hw-info wlan1 as-value ]
ranges=2312-2732/5/b;g;gn20;gn40;2484-2484/5/b;g;gn20;gn40;rx-chains=0;1;tx-chains=0;1

Output is 1D array so you can easily get interested property value

[admin@1p_DUT_wAP ac] /interface wireless info> :put ([hw-info wlan1 as-value ]->"tx-chains")      
0;1

Always check what value and type command returns

Lets say we want to get gateway of specific route using as-value, if we execute following command it will return nothing

[admin@rack1_b36_CCR1009] /ip address> :put ([/ip route print as-value where gateway="ether1"]->"gateway") 


Command assumes that output will be 1D array from which we could extract element gateway.

At first lets check if print is actually find anything:

[admin@rack1_b36_CCR1009] /ip address> :put ([/ip route print as-value where gateway="ether1"])  
.id=*400ae12f;distance=255;dst-address=111.111.111.1/32;gateway=ether1;pref-src=111.111.111.1

So obviously there is something wrong with variable itself or variable type returned. Lets check it more closely:

[admin@rack1_b36_CCR1009] /ip address> :global aa ([/ip route print as-value where gateway="ether1"
])       
[admin@rack1_b36_CCR1009] /ip address> :environment print 
aa={{.id=*400ae12f; distance=255; dst-address=111.111.111.1/32; gateway={"ether1"}; pref-src=111.11
1.111.1}}

Now it is clear that returned value is 2D array with one element. So the right sequence to extract gateway will be:

  • get 2d array
  • get first element
  • get "gateway" from picked element
[admin@rack1_b36_CCR1009] /ip address> :put ([:pick [/ip route print as-value where gateway="ether1"] 0]->"gateway")  
ether1

Be careful when adding array to string

If you want to print an array or add an array to existing string, be very careful as it may lead to unexpected results. For example ,we have array with two elements and we want to print the array value on screen:

[admin@1p_DUT_wAP ac] /> :global array {"cccc", "ddddd"}
[admin@1p_DUT_wAP ac] /> :put ("array value is: " . $array )       
array value is: cccc;array value is: ddddd

Obviously this is not what we expected, because what . does is adds string to each array element and then prints the output. Instead you need to convert to string first:

[admin@1p_DUT_wAP ac] /> :put ("array value is: " . [:tostr  $array] )
array value is: cccc;ddddd

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