If I were to cast bless on the front lines and got attacked would the spell end immediately?
Bless: If you take damage equal to or greater than your level from a reaction or free action triggered by this action, your spell is disrupted and immediately dismissed.
My frontline Cleric can cast this spell I'm just wondering if it's worth it to keep concentrating on it for the duration of the fight. I would need to spend an action each round to keep it active, if I'm attacked at any point the spell automatically ends if I take damage equal to or greater than My level?
RAW, only reactions and free actions can do this, not regular attacks, and it has to be enough damage in a single attack, so as long as you stay away from creatures that have attacks of opportunity and can deal decent damage, you should be fine. I haven't seen many melee casters in my group so far, but when they did, it usually worked out fine. I'm currently playing a goblin cleric and, with decent AC, a reach weapon and some smart positioning, I've managed not to waste any spells.
Invest in your AC to avoid as many hits as you can. At some point, it would probably also be good to get Steady Spellcasting, a level 4 cleric feat that allows you to take more damage without losing spells. Other options that mitigate damage, such as resistance, or that allow you to move more easily without provoking (some skill feats and ancestry feats, mainly) can also help. So yes, it's risky, but feasible and potentially very fun.
RAW, only reactions and free actions can do this, not regular attacks
And it's not reactions and free actions. It's reactions and free actions where the provoking trigger was the "Concentrate on a Spell" action. So if you use an action to Stride from a character and provoke an AoO, then Concentrate on a Spell, you would not lose the spell you are concentrating on.
So no, just getting hit while the spell is up does not hinder it. Getting hit during casting (Be it AoO, Readied action, or other) does, and so does getting hit during the Concentrate on a Spell action, but that is much rarer as few things can disrupt you there (Readied actions might be able to, IDK.)
A readied action allows you to attack as a reaction with a trigger you designate. So a character could ready an action to attack when a caster concentrates on a spell, and that damage, if the readied action hit, could disrupt the spell (since it is damage from a reaction where the trigger is the "Concentrate on a Spell" action). And since they have to burn two actions on that, I'm not sure it's going to be everyone's first move.
Spoiler:RAW, only reactions and free actions can do this, not regular attacksAnd it's not reactions and free actions. It's reactions and free actions where the provoking trigger was the "Concentrate on a Spell" action. So if you use an action to Stride from a character and provoke an AoO, then Concentrate on a Spell, you would not lose the spell you are concentrating on.
So no, just getting hit while the spell is up does not hinder it. Getting hit during casting (Be it AoO, Readied action, or other) does, and so does getting hit during the Concentrate on a Spell action, but that is much rarer as few things can disrupt you there (Readied actions might be able to, IDK.)A readied action allows you to attack as a reaction with a trigger you designate. So a character could ready an action to attack when a caster concentrates on a spell, and that damage, if the readied action hit, could disrupt the spell (since it is damage from a reaction where the trigger is the "Concentrate on a Spell" action). And since they have to burn two actions on that, I'm not sure it's going to be everyone's first move.
Right, I had forgot that it only applied with the concentrate action.