Is Russia a dog-friendly country?(Vladivostok, Moscow, St.Peterburg. etc.)

I live in Moscow and used to have a labrador myself. I regret to say that while keeping a dog in the city will likely be fine (depending on your exact location), traveling and visiting tourist spots with it should be fairly difficult, especially without a car. Such travel will likely be stressful for your dog, and you.

• In public places, on buses and even in parks you are expected to keep the dog leashed and muzzled, even if the dog is friendly (I know perfectly well that all labradors are harmless sweethearts, but not everyone else does!). Personally, I would just apply common sense and muzzle the dog if there are many people or vehicles nearby, but give it more freedom otherwise. (source)
• The dog must be caged to be transported in the Moscow metro, unless it's a service dog. Realistically speaking, you will have to hail a taxi/uber or use buses, trolleybuses and streetcars which let dogs inside (you will be expected to muzzle it though) to move around the city.
• Very few museums would allow dogs inside, unless they are service dogs.
• There used to be a notable number of dangerous dogs which could attack other dogs and people. Nowadays it seems to be no longer a problem, and I see plenty of good-natured breeds such as Golden Retrievers and Corgis having quality time in local parks. Regardless, you should always stay alert for breeds that may hurt your dog if trained poorly (e.g. Pit Bull terriers, Rottweilers, Caucasian shepherds, etc.), guard dogs (especially when in the countryside) and groups of strays.
• Moscow in particular has had several bad cases of mass poisonings of dogs in the city. When walking your dog, never let it pick up any food from the ground, or accept snacks from strangers, it may put your dog's life in danger.
• Generally, other people's reaction to your dog will not always be positive, unlike e.g. San Francisco where they get almost universal love. Most people will pretend to ignore them, some will love them, some will feel uneasy or scared, and every once in a while you'll run across a nutjob who will quite vocally and rudely state their dislike of canines.

Finally, a couple of more general things to note:

• Carefully read the rules of transporting dogs on railways and contact the railway company beforehand to make sure they will let your dog on the train.
• Always carry a muzzle, a leash, and a good amount of spare waste bags with you.
• Make sure you know what it takes to import your dog to Russia, and then return home.

To summarize, traveling with a medium-sized dog across Russia should be possible, but will unlikely be fun for the dog, and will prevent you from taking in most local sights (especially if you're traveling alone).

• There are cars in Russian trains which are suited for travelling with pets. Note that they expect you to buy the whole compartment if you are travelling with big dog.
• I'm not sure that your dog will be comfortable staying on the train all day.
• On the street big dogs are expected to wear a muzzle.
• I'm pretty sure that absolute majority of museums are not dog-friendly. Finding dog-friendly restaurants/hotels should not be very hard.

From my experiences in Russia, dogs are treated very poorly. When I visited Maykop, I saw dogs eating another dog, right next to the main market, on the street. People in traffic were honking at these wild dogs, and one man got out of his car to kick the dogs. I was very shocked to see such horrors. There were plenty of stray dogs, and one well fed female dog followed me through the market.

Dogs are generally treated as dogs and not as people in Russia. Since you take good care of your dog, it shouldn't be a problem. But understand that Russians generally do not respect dogs.