Why is it "loggable" rather than "logable"?

I am using 'loggable' in the name of an interface written in a .NET programming language. It is among the many words that make sense in a programming context but aren't (yet) listed in English Dictionaries, as are serializable, deserialization, and multiton. Loggable seems like the correct spelling to me, but I can't pinpoint the reason. Similar words such as floggable and taggable have double 'g', but Google search also returns usage of their single 'g' counterparts, albeit the single 'g' seems to be less widespread.

Does anyone know a reason my brain likes "loggable" as opposed to "logable" for the correct spelling? A concrete rule would be great.

Yes, loggable appears to be in use and preferred over logable. You appear to prefer it to because you are accustomed to the pattern with other words such as the ones listed in your post.

Most people here will tell you that there are no concrete rules in English. But as a rule of thumb, for words ending with a single consonant, if the suffix begins with a vowel, then the afore-noted consonant is doubled. Therefore, log becomes loggable.

There are, I'm sure, many exceptions to this rule, some of which can be explained with caveats involving stress and other whatnots.

Here is John Lawler's explanation from the comments:

No, the rule is: if the vowel was short in Middle English (/ɪ ɛ æ ɔ ə/) and it uses only one vowel letter and it's in a syllable ended by a consonant, then you double the consonant in spelling. If you don't, you get a vowel that was long in Middle English, and is now tense, respectively, /ay i e o u/. If you know Middle English, this is not a problem. If you don't, however, it is.

That's because it's a Latin infinitive: lego, legere, legi, lectus 'read'. Legibilis is a Latin adjective, which was borrowed along with dozens of other Latin words from the same root. Look up any verb in a Latin dictionary (they're cheap at used bookstores) and you'll find a half-dozen words from the same root that we use in English, already minted by the Romans and imported into English in one of the waves of Latin and French that poured into England.