terraform/terraform/eval_output.go

136 lines
4.3 KiB
Go

package terraform
import (
"fmt"
"log"
"github.com/hashicorp/hcl/v2"
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/plans"
"github.com/hashicorp/terraform/states"
)
// EvalDeleteOutput is an EvalNode implementation that deletes an output
// from the state.
type EvalDeleteOutput struct {
Addr addrs.AbsOutputValue
}
// TODO: test
func (n *EvalDeleteOutput) Eval(ctx EvalContext) (interface{}, error) {
state := ctx.State()
if state == nil {
return nil, nil
}
state.RemoveOutputValue(n.Addr)
return nil, nil
}
// EvalWriteOutput is an EvalNode implementation that writes the output
// for the given name to the current state.
type EvalWriteOutput struct {
Addr addrs.OutputValue
Sensitive bool
Expr hcl.Expression
// ContinueOnErr allows interpolation to fail during Input
ContinueOnErr bool
}
// TODO: test
func (n *EvalWriteOutput) Eval(ctx EvalContext) (interface{}, error) {
addr := n.Addr.Absolute(ctx.Path())
// This has to run before we have a state lock, since evaluation also
// reads the state
val, diags := ctx.EvaluateExpr(n.Expr, cty.DynamicPseudoType, nil)
// We'll handle errors below, after we have loaded the module.
state := ctx.State()
if state == nil {
return nil, nil
}
changes := ctx.Changes() // may be nil, if we're not working on a changeset
// handling the interpolation error
if diags.HasErrors() {
if n.ContinueOnErr || flagWarnOutputErrors {
log.Printf("[ERROR] Output interpolation %q failed: %s", n.Addr.Name, diags.Err())
// if we're continuing, make sure the output is included, and
// marked as unknown. If the evaluator was able to find a type
// for the value in spite of the error then we'll use it.
n.setValue(addr, state, changes, cty.UnknownVal(val.Type()))
return nil, EvalEarlyExitError{}
}
return nil, diags.Err()
}
n.setValue(addr, state, changes, val)
return nil, nil
}
func (n *EvalWriteOutput) setValue(addr addrs.AbsOutputValue, state *states.SyncState, changes *plans.ChangesSync, val cty.Value) {
if val.IsKnown() && !val.IsNull() {
// The state itself doesn't represent unknown values, so we null them
// out here and then we'll save the real unknown value in the planned
// changeset below, if we have one on this graph walk.
log.Printf("[TRACE] EvalWriteOutput: Saving value for %s in state", addr)
stateVal := cty.UnknownAsNull(val)
state.SetOutputValue(addr, stateVal, n.Sensitive)
} else {
log.Printf("[TRACE] EvalWriteOutput: Removing %s from state (it is now null)", addr)
state.RemoveOutputValue(addr)
}
// If we also have an active changeset then we'll replicate the value in
// there. This is used in preference to the state where present, since it
// *is* able to represent unknowns, while the state cannot.
if changes != nil {
// For the moment we are not properly tracking changes to output
// values, and just marking them always as "Create" or "Destroy"
// actions. A future release will rework the output lifecycle so we
// can track their changes properly, in a similar way to how we work
// with resource instances.
var change *plans.OutputChange
if !val.IsNull() {
change = &plans.OutputChange{
Addr: addr,
Sensitive: n.Sensitive,
Change: plans.Change{
Action: plans.Create,
Before: cty.NullVal(cty.DynamicPseudoType),
After: val,
},
}
} else {
change = &plans.OutputChange{
Addr: addr,
Sensitive: n.Sensitive,
Change: plans.Change{
// This is just a weird placeholder delete action since
// we don't have an actual prior value to indicate.
// FIXME: Generate real planned changes for output values
// that include the old values.
Action: plans.Delete,
Before: cty.NullVal(cty.DynamicPseudoType),
After: cty.NullVal(cty.DynamicPseudoType),
},
}
}
cs, err := change.Encode()
if err != nil {
// Should never happen, since we just constructed this right above
panic(fmt.Sprintf("planned change for %s could not be encoded: %s", addr, err))
}
log.Printf("[TRACE] EvalWriteOutput: Saving %s change for %s in changeset", change.Action, addr)
changes.RemoveOutputChange(addr) // remove any existing planned change, if present
changes.AppendOutputChange(cs) // add the new planned change
}
}