Adds the ability to target resources within modules, like:
module.mymod.aws_instance.foo
And the ability to target all resources inside a module, like:
module.mymod
Closes#1434
This reimplements my prior attempt at nipping issues where a plan did
not yield the same cycle an apply did. My prior attempt was to have
ctx.Validate generate a "Verbose" worst-case graph. It turns out that
skipping PruneDestroyTransformer to generate this graph misses important
heuristics that prevent cycles by dropping destroy nodes that are
determined to be unused.
This resulted in Validate improperly failing in scenarios where these
heuristics would have broken the cycle.
We detected the problem during the work on #1781 and worked around the
issue by reverting to the non-Verbose graph in Validate.
This commit accomplishes the original goal in a better way - by
generating the full graph and checking it once Plan has calculated the
diff. This guarantees that any graph issue that would be caught by Apply
will be caught by Plan.
When you specify `-verbose` you'll get the whole graph of operations,
which gives a better idea of the operations terraform performs and in
what order.
The DOT graph is now generated with a small internal library instead of
simple string building. This allows us to ensure the graph generation is
as consistent as possible, among other benefits.
We set `newrank = true` in the graph, which I've found does just as good
a job organizing things visually as manually attempting to rank the nodes
based on depth.
This also fixes `-module-depth`, which was broken post-AST refector.
Modules are now expanded into subgraphs with labels and borders. We
have yet to regain the plan graphing functionality, so I removed that
from the docs for now.
Finally, if `-draw-cycles` is added, extra colored edges will be drawn
to indicate the path of any cycles detected in the graph.
A notable implementation change included here is that
{Reverse,}DepthFirstWalk has been made deterministic. (Before it was
dependent on `map` ordering.) This turned out to be unnecessary to gain
determinism in the final DOT-level implementation, but it seemed
a desirable enough of a property that I left it in.
The `TargetTransform` was dropping provisioner nodes, which caused graph
validation to fail with messages about uninitialized provisioners when a
`terraform destroy` was attempted.
This was because `destroy` flops the dependency calculation to try and
address any nodes in the graph that "depend on" the target node. But we
still need to keep the provisioner node in the graph.
Here we switch the strategy for filtering nodes to only drop
addressable, non-targeted nodes. This should prevent us from having to
whitelist nodes to keep in the future.
closes#1541
Most CBD-related cycles include destroy nodes, and destroy nodes were
all being pruned from the graph before staring the Validate walk.
In practice this meant that we had scenarios that would error out with
graph cycles on Apply that _seemed_ fine during Plan.
This introduces a Verbose option to the GraphBuilder that tells it to
generate a "worst-case" graph. Validate sets this to true so that cycle
errors will always trigger at this step if they're going to happen.
(This Verbose option will be exposed as a CLI flag to `terraform graph`
in a second incoming PR.)
refs #1651
Adds an "alias" field to the provider which allows creating multiple instances
of a provider under different names. This provides support for configurations
such as multiple AWS providers for different regions. In each resource, the
provider can be set with the "provider" field.
(thanks to Cisco Cloud for their support)
When the `prevent_destroy` flag is set on a resource, any plan that
would destroy that resource instead returns an error. This has the
effect of preventing the resource from being unexpectedly destroyed by
Terraform until the flag is removed from the config.
fixes#1508
In a DESTROY/CREATE scenario, the plan diff will be run against the
state of the old instance, while the apply diff will be run against an
empty state (because the state is cleared when the destroy node does its
thing.)
For complex attributes, this can result in keys that seem to disappear
between the two diffs, when in reality everything is working just fine.
Same() needs to take into account this scenario by analyzing NewRemoved
and treating as "Same" a diff that does indeed have that key removed.
CBD used to "borrow" the last slot of of the Tainted list in the State,
but as of #1078 it uses its own list. This seems like just a block of
old code that didn't get cleaned up from the refactor. Deposed resources
get their own destroy nodes, so they don't have to mess with the main
destroy node.
The provider config was not being properly merged across module
boundaries during the Input walk over the graph, so when a provider was
configured at the top level, resources in modules could improperly
trigger a request for input for a provider attribute that's already
defined.
Instead of returning UnknownVariableValue every time, attempt to return
the real value. If we don't find it, return unknown value. This fixes
removing outputs from state on refresh.
Only used in targets for now. The plan is to use this for interpolation
as well.
This allows us to target:
* individual resources expanded by `count` using bracket / index notation.
* deposed / tainted resources with an `InstanceType` field after name
Docs to follow.
Add `-target=resource` flag to core operations, allowing users to
target specific resources in their infrastructure. When `-target` is
used, the operation will only apply to that resource and its
dependencies.
The calculated dependencies are different depending on whether we're
running a normal operation or a `terraform destroy`.
Generally, "dependencies" refers to ancestors: resources falling
_before_ the target in the graph, because their changes are required to
accurately act on the target.
For destroys, "dependencies" are descendents: those resources which fall
_after_ the target. These resources depend on our target, which is going
to be destroyed, so they should also be destroyed.
We were previously only recording the schema version on refresh. This
caused the state to be incorrectly written after a `terraform apply`
causing subsequent commands to run the state through an unnecessary
migration.
Providers get a per-resource SchemaVersion integer that they can bump
when a resource's schema changes format. Each InstanceState with an
older recorded SchemaVersion than the cureent one is yielded to a
`MigrateSchema` function to be transformed such that it can be addressed
by the current version of the resource's Schema.
Deposed instances need to be stored as a list for certain pathological
cases where destroys fail for some reason (e.g. upstream API failure,
Terraform interrupted mid-run). Terraform needs to be able to remember
all Deposed nodes so that it can clean them up properly in subsequent
runs.
Deposed instances will now never touch the Tainted list - they're fully
managed from within their own list.
Added a "multiDepose" test case that walks through a scenario to
exercise this.
After a lot of fun debugging with @mitchellh we finally have a diagnosis
for #1056.
I'm going to attempt to reproduce the diagnosis in prose to test out my
understanding.
----
The `DestroyTransformer` runs twice:
* `DestroyPrimary` mode creates destroy nodes for normal resources
* `DestroyTainted` mode creates destroy nodes for tainted resources
These destroy nodes are specializations of `GraphConfigNode`, which has
a `DynamicExpand` step.
In `DynamicExpand` we have a race condition between the normal destroy
node and the tainted destroy node for a given resource when
`CreateBeforeDestroy` is off.
The `DestroyTainted` `GraphConfigNode` must run the `TaintedTransform`
to draw out tainted nodes, since it is reponsible for destroying them
for replacement.
The `DestroyPrimary` `GraphConfigNode` _also_ runs `TaintedTransform` -
this is to catch `Deposed` nodes from CBD, which are piggy backing on
the end of the `Tainted` list.
Here's the bug: when CBD is off and you start an apply with a tainted
resource in your state, both `DestroyPrimary` and `DestroyTainted` catch
it and create their own `graphNodeTaintedResource` in their respective
subgraphs.
If parallelism is disabled, this doesn't happen because the
`DestroyPrimary` subgraph resolves completely before the
`DestroyTainted` node does its `DynamicExpand`, so the `Tainted` list
has been cleared by the time `DestroyTainted` is expanding. With
parallelism, each of these two subgraphs plays out in its own goroutine
simultaneously, and each picks up the tainted resource(s) that the apply
starts with. So you get two `graphNodeTaintedResource` nodes, and two
destroys.
This band-aid fixes that by skipping the TaintedTransform alltogether in
the `DestroyPrimary` node if CBD is off.
A better fix will follow, which involves reworking the `Deposed` concept
so it no longer piggybacks on `Tainted`.
fixes#1056
/cc @sethvargo
This was causing a race with whichever provider was configured first
would "win" the configuration slot. We need to make sure to append the
unique provider name to the end of the key.
Note: this doesn't have tests. We don't test this yet. :(
/cc @sethvargo
Prior to this commit, we'd only persist the result of calling Input if
any input was given (len(result) > 0). The result was that every module
would also repeat asking for input even if there was no input to be
asked for.
This commit makes it so that if no input was received, we still set a
sentinel so that modules don't re-ask.
