9 Commits (deb82daf2bbb28ccaf6d52142b4e74428ca21e72)

Author	SHA1	Message	Date
Alisdair McDiarmid	39de3ebec7	cli: Fix init failure with deleted cache ... The init command needs to initialize a backend, in order to access state, in turn to derive provider requirements from state. The backend initialization step requires building provider factories, which previously would fail if a lockfile was present without a corresponding local provider cache. This commit ensures that in this situation only, errors with the provider factories are temporarily ignored. This allows us to continue to initialize the backend, fetch providers, and then report any errors as necessary.	5 years ago
Martin Atkins	d09510a8fb	command: Early error message for missing cache entries of locked providers ... In the original incarnation of Meta.providerFactories we were returning into a Meta.contextOpts whose signature didn't allow it to return an error directly, and so we had compromised by making the provider factory functions themselves return errors once called. Subsequent work made Meta.contextOpts need to return an error anyway, but at the time we neglected to update our handling of the providerFactories result, having it still defer the error handling until we finally instantiate a provider. Although that did ultimately get the expected result anyway, the error ended up being reported from deep in the guts of a Terraform Core graph walk, in whichever concurrently-visited graph node happened to try to instantiate the plugin first. This meant that the exact phrasing of the error message would vary between runs and the reporting codepath didn't have enough context to given an actionable suggestion on how to proceed. In this commit we make Meta.contextOpts pass through directly any error that Meta.providerFactories produces, and then make Meta.providerFactories produce a special error type so that Meta.Backend can ultimately return a user-friendly diagnostic message containing a specific suggestion to run "terraform init", along with a short explanation of what a provider plugin is. The reliance here on an implied contract between two functions that are not directly connected in the callstack is non-ideal, and so hopefully we'll revisit this further in future work on the overall architecture of the CLI layer. To try to make this robust in the meantime though, I wrote it to use the errors.As function to potentially unwrap a wrapped version of our special error type, in case one of the intervening layers is changed at some point to wrap the downstream error before returning it.	5 years ago
Martin Atkins	8d193ad268	core: Simplify and centralize plugin availability checks ... Historically the responsibility for making sure that all of the available providers are of suitable versions and match the appropriate checksums has been split rather inexplicably over multiple different layers, with some of the checks happening as late as creating a terraform.Context. We're gradually iterating towards making that all be handled in one place, but in this step we're just cleaning up some old remnants from the main "terraform" package, which is now no longer responsible for any version or checksum verification and instead just assumes it's been provided with suitable factory functions by its caller. We do still have a pre-check here to make sure that we at least have a factory function for each plugin the configuration seems to depend on, because if we don't do that up front then it ends up getting caught instead deep inside the Terraform runtime, often inside a concurrent graph walk and thus it's not deterministic which codepath will happen to catch it on a particular run. As of this commit, this actually does leave some holes in our checks: the command package is using the dependency lock file to make sure we have exactly the provider packages we expect (exact versions and checksums), which is the most crucial part, but we don't yet have any spot where we make sure that the lock file is consistent with the current configuration, and we are no longer preserving the provider checksums as part of a saved plan. Both of those will come in subsequent commits. While it's unusual to have a series of commits that briefly subtracts functionality and then adds back in equivalent functionality later, the lock file checking is the only part that's crucial for security reasons, with everything else mainly just being to give better feedback when folks seem to be using Terraform incorrectly. The other bits are therefore mostly cosmetic and okay to be absent briefly as we work towards a better design that is clearer about where that responsibility belongs.	5 years ago
Martin Atkins	65e0c448a0	workdir: Start of a new package for working directory state management ... Thus far our various interactions with the bits of state we keep associated with a working directory have all been implemented directly inside the "command" package -- often in the huge command.Meta type -- and not managed collectively via a single component. There's too many little codepaths reading and writing from the working directory and data directory to refactor it all in one step, but this is an attempt at a first step towards a future where everything that reads and writes from the current working directory would do so via an object that encapsulates the implementation details and offers a high-level API to read and write all of these session-persistent settings. The design here continues our gradual path towards using a dependency injection style where "package main" is solely responsible for directly interacting with the OS command line, the OS environment, the OS working directory, the stdio streams, and the CLI configuration, and then communicating the resulting information to the rest of Terraform by wiring together objects. It seems likely that eventually we'll have enough wiring code in package main to justify a more explicit organization of that code, but for this commit the new "workdir.Dir" object is just wired directly in place of its predecessors, without any significant change of code organization at that top layer. This first commit focuses on the main files and directories we use to find provider plugins, because a subsequent commit will lightly reorganize the separation of concerns for plugin launching with a similar goal of collecting all of the relevant logic together into one spot.	5 years ago
James Bardin	863963e7a6	de-linting	5 years ago
Martin Atkins	89b05050ec	core: Functional-style API for terraform.Context ... Previously terraform.Context was built in an unfortunate way where all of the data was provided up front in terraform.NewContext and then mutated directly by subsequent operations. That made the data flow hard to follow, commonly leading to bugs, and also meant that we were forced to take various actions too early in terraform.NewContext, rather than waiting until a more appropriate time during an operation. This (enormous) commit changes terraform.Context so that its fields are broadly just unchanging data about the execution context (current workspace name, available plugins, etc) whereas the main data Terraform works with arrives via individual method arguments and is returned in return values. Specifically, this means that terraform.Context no longer "has-a" config, state, and "planned changes", instead holding on to those only temporarily during an operation. The caller is responsible for propagating the outcome of one step into the next step so that the data flow between operations is actually visible. However, since that's a change to the main entry points in the "terraform" package, this commit also touches every file in the codebase which interacted with those APIs. Most of the noise here is in updating tests to take the same actions using the new API style, but this also affects the main-code callers in the backends and in the command package. My goal here was to refactor without changing observable behavior, but in practice there are a couple externally-visible behavior variations here that seemed okay in service of the broader goal: - The "terraform graph" command is no longer hooked directly into the core graph builders, because that's no longer part of the public API. However, I did include a couple new Context functions whose contract is to produce a UI-oriented graph, and _for now_ those continue to return the physical graph we use for those operations. There's no exported API for generating the "validate" and "eval" graphs, because neither is particularly interesting in its own right, and so "terraform graph" no longer supports those graph types. - terraform.NewContext no longer has the responsibility for collecting all of the provider schemas up front. Instead, we wait until we need them. However, that means that some of our error messages now have a slightly different shape due to unwinding through a differently-shaped call stack. As of this commit we also end up reloading the schemas multiple times in some cases, which is functionally acceptable but likely represents a performance regression. I intend to rework this to use caching, but I'm saving that for a later commit because this one is big enough already. The proximal reason for this change is to resolve the chicken/egg problem whereby there was previously no single point where we could apply "moved" statements to the previous run state before creating a plan. With this change in place, we can now do that as part of Context.Plan, prior to forking the input state into the three separate state artifacts we use during planning. However, this is at least the third project in a row where the previous API design led to piling more functionality into terraform.NewContext and then working around the incorrect order of operations that produces, so I intend that by paying the cost/risk of this large diff now we can in turn reduce the cost/risk of future projects that relate to our main workflow actions.	5 years ago
Martin Atkins	36d0a50427	Move terraform/ to internal/terraform/ ... This is part of a general effort to move all of Terraform's non-library package surface under internal in order to reinforce that these are for internal use within Terraform only. If you were previously importing packages under this prefix into an external codebase, you could pin to an earlier release tag as an interim solution until you've make a plan to achieve the same functionality some other way.	5 years ago
Martin Atkins	31349a9c3a	Move configs/ to internal/configs/ ... This is part of a general effort to move all of Terraform's non-library package surface under internal in order to reinforce that these are for internal use within Terraform only. If you were previously importing packages under this prefix into an external codebase, you could pin to an earlier release tag as an interim solution until you've make a plan to achieve the same functionality some other way.	5 years ago
Martin Atkins	ffe056bacb	Move command/ to internal/command/ ... This is part of a general effort to move all of Terraform's non-library package surface under internal in order to reinforce that these are for internal use within Terraform only. If you were previously importing packages under this prefix into an external codebase, you could pin to an earlier release tag as an interim solution until you've make a plan to achieve the same functionality some other way.	5 years ago